AC — Alternating current
Generation, storage & electrification · Technical term · Electric power — Electric current that periodically changes direction.
In practice: The inverter delivers AC power to the building panel.
Searchable USA Utilities Acronym Database
TIMETREX REFERENCE LIBRARY · UTILITIES
USA UtilitiesAcronym Database
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480 meanings18 subjectsU.S. focused
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Full alphabetical reference · 480 meanings
ACE — Area Control Error
Grid operations & reliability · Technical term · Electric power — A control quantity reflecting a balancing area's interchange deviation and frequency-related obligations.
In practice: Operators monitor ACE while regulating generation.
The formal calculation includes defined terms and adjustments; this is a conceptual explanation.
ACVG — Alternating-current voltage gradient
Natural gas & pipeline systems · Technical term · Natural gas — A survey method using an alternating-current signal to help locate pipeline coating defects.
In practice: A field team includes ACVG in its coating assessment plan.
ADMS — Advanced distribution management system
Electric equipment & distribution · Technical term · Electric power — An integrated platform supporting distribution monitoring, analysis, outage response, and control.
In practice: An ADMS combines a network model with real-time feeder information.
AFUDC — Allowance for funds used during construction
Markets, rates & planning · Market or planning term · U.S. utility markets — An accounting allowance for financing costs associated with construction under applicable rules.
In practice: A utility explains AFUDC in the cost of a new plant.
AGC — Automatic generation control
Grid operations & reliability · Technical term · Electric power — Automatic adjustment of generator output to help maintain the required power balance and frequency response.
In practice: AGC changes unit setpoints as the balancing signal changes.
AIS — Air-insulated switchgear
Electric equipment & distribution · Technical term · Electric power — Switchgear using air as the principal external insulation between energized components.
In practice: A site layout reserves the clearances needed for AIS.
AL — Action level
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A concentration threshold that triggers specified actions under the relevant rule.
In practice: A utility checks which follow-up duties apply after an AL exceedance.
An action level is not interchangeable with an MCL.
AMI — Advanced metering infrastructure
Metering, billing & customer service · Technical term · Cross-utility — Meters, communications, and supporting systems that collect interval usage data and enable defined two-way functions.
In practice: AMI helps a utility collect readings and identify selected service events.
AMR — Automated meter reading
Metering, billing & customer service · Technical term · Cross-utility — Technology that collects meter readings without manually reading each meter display.
In practice: A drive-by AMR system collects consumption readings.
AMR does not necessarily provide the two-way capabilities associated with AMI.
AOC — Abnormal operating condition
Natural gas & pipeline systems · Technical term · Natural gas — A condition identified by a pipeline operator that may indicate malfunction, deviation, or a hazard under the applicable OQ framework.
In practice: An OQ evaluation includes recognizing and responding to relevant AOCs.
AOP — Advanced oxidation process
Drinking water & distribution · Technical term · Drinking water — A treatment process designed to generate highly reactive species for contaminant destruction.
In practice: A plant evaluates an AOP after membrane treatment.
API — Application programming interface
Controls, communications & cybersecurity · Technical term · Cross-utility — A defined interface through which software exchanges data or requests functions.
In practice: A billing integration uses an API to exchange approved account data.
APPA — American Public Power Association
U.S. agencies & organizations · Organization · U.S. specific — The U.S. association representing community-owned electric utilities.
In practice: A public power utility uses APPA industry resources.
ARR — Auction revenue right
Markets, rates & planning · Market or planning term · U.S. utility markets — A right to allocations of qualifying transmission-right auction revenue under a market's rules.
In practice: A load-serving entity evaluates its ARR allocation.
ASV — Automatic shutoff valve
Natural gas & pipeline systems · Technical term · Natural gas — A valve designed to close automatically under specified conditions.
In practice: A pipeline safety plan identifies segments with ASVs.
ATC — Available Transfer Capability
Grid operations & reliability · Technical term · Electric power — The remaining transfer capability available for additional commercial activity after applicable commitments and margins.
In practice: A transmission customer reviews ATC before requesting service.
Use the applicable methodology and time period when comparing ATC values.
BA — Balancing Authority
Grid operations & reliability · Technical term · Electric power — The entity responsible for balancing generation, interchange, and load within its balancing area.
In practice: The BA monitors supply and demand continuously.
BAA — Balancing Authority Area
Grid operations & reliability · Technical term · Electric power — The metered electrical boundary within which a balancing authority maintains its balance responsibilities.
In practice: A generator is assigned to the appropriate BAA for operational accounting.
Bcf — Billion cubic feet
Units, quantities & symbols · Unit or symbol · Cross-utility — A gas-volume unit equal to one billion cubic feet under the stated reference conditions.
In practice: A regional inventory is expressed in Bcf.
BCF
BES — Bulk Electric System
Grid operations & reliability · Technical term · Electric power — The facilities and equipment within NERC's defined bulk-system scope, subject to specified inclusions and exclusions.
In practice: A compliance review first determines whether the facility falls within the BES definition.
BES is a defined regulatory term; it is not a synonym for every electric wire.
BESS — Battery energy storage system
Generation, storage & electrification · Technical term · Electric power — Batteries, power conversion, controls, and supporting equipment operated as a storage system.
In practice: A BESS shifts solar output to a later time.
BEV — Battery electric vehicle
Generation, storage & electrification · Technical term · Electric power — A vehicle propelled by an electric motor using energy stored in a battery.
In practice: A BEV fleet requires charging infrastructure at its depot.
BMP — Best management practice
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A structural or nonstructural measure used to prevent or reduce pollution or other adverse impacts.
In practice: A site uses appropriate BMPs to manage sediment runoff.
BMS — Battery management system
Generation, storage & electrification · Technical term · Electric power — Controls that monitor battery conditions and manage operation within defined limits.
In practice: The BMS monitors cell voltages and temperature.
BNR — Biological nutrient removal
Wastewater treatment & resource recovery · Technical term · Wastewater — Biological treatment designed to reduce nutrients such as nitrogen and phosphorus.
In practice: A plant upgrade adds BNR process zones.
BOD — Biochemical oxygen demand
Wastewater treatment & resource recovery · Technical term · Wastewater — A measure of oxygen consumed by biological processes in a sample under specified test conditions.
In practice: A plant compares influent and effluent BOD to assess treatment performance.
BOD also means basis of design in engineering documents.
BOD — Basis of design
Asset management & field projects · Technical term · Cross-utility — The documented technical assumptions and approach used to develop a design.
In practice: A pump-station BOD explains duty conditions and design choices.
Wastewater laboratory reports use BOD for biochemical oxygen demand.
BOD5 — Five-day biochemical oxygen demand
Wastewater treatment & resource recovery · Technical term · Wastewater — BOD measured over the specified five-day laboratory test period.
In practice: An effluent report identifies the result specifically as BOD5.
BPA — Bonneville Power Administration
U.S. agencies & organizations · Organization · U.S. specific — The federal power marketing administration serving the Pacific Northwest through power and transmission activities.
In practice: A public utility purchases eligible power from BPA.
BPS — Bulk power system
Grid operations & reliability · Technical term · Electric power — The interconnected generation and transmission system that supplies large-scale electricity needs.
In practice: A planning report discusses risks affecting the BPS across a wide region.
BTM — Behind the meter
Generation, storage & electrification · Technical term · Electric power — Located on the customer side of the billing meter.
In practice: A BTM battery can serve on-site loads under its operating agreement.
Btu — British thermal unit
Units, quantities & symbols · Unit or symbol · Cross-utility — A customary unit of heat energy used in fuel and utility accounting.
In practice: A gas statement reports the fuel's heating value using Btu.
Different Btu conventions exist; follow the specified measurement basis.
BWR — Boiling water reactor
Generation, storage & electrification · Technical term · Electric power — A nuclear reactor design that produces steam by boiling water in the reactor vessel.
In practice: A plant description identifies its generating unit as a BWR.
CAIDI — Customer Average Interruption Duration Index
Grid operations & reliability · Performance metric · Electric power — Customer interruption minutes divided by customer interruptions, expressing average duration per interruption.
In practice: For the same reporting basis, CAIDI equals SAIDI divided by SAIFI when SAIFI is nonzero.
This measures restoration duration per interruption, not total annual outage time per customer.
CAISO — California Independent System Operator
U.S. agencies & organizations · Organization · U.S. specific — The organization operating much of California's high-voltage grid and administering related electricity markets.
In practice: A resource follows CAISO interconnection and market procedures.
Its market activities extend beyond the footprint of its balancing authority.
CAPEX — Capital expenditure
Asset management & field projects · Technical term · Cross-utility — Spending treated as an investment in assets under the applicable accounting policy.
In practice: A utility proposes CAPEX for a new substation.
CBA — Collective bargaining agreement
Workforce, time & administration · Workforce term · Cross-utility — A negotiated agreement governing employment terms for a represented workforce.
In practice: A scheduler checks relevant CBA provisions for assignments.
CBM — Capacity Benefit Margin
Grid operations & reliability · Technical term · Electric power — Transfer capability reserved for load-serving entities to access external generation for reliability needs.
In practice: A resource-adequacy plan explains its CBM assumption.
CBM — Condition-based maintenance
Asset management & field projects · Technical term · Cross-utility — Maintenance initiated or prioritized using observed equipment condition.
In practice: An inspection finding triggers a CBM work order.
Transmission planning uses CBM for capacity benefit margin.
CBOD5 — Five-day carbonaceous biochemical oxygen demand
Wastewater treatment & resource recovery · Technical term · Wastewater — The five-day BOD measurement with nitrogenous oxygen demand inhibited under the method.
In practice: A permit specifies CBOD5 rather than total BOD5.
CCF — Hundred cubic feet
Units, quantities & symbols · Unit or symbol · Cross-utility — A volume unit equal to one hundred cubic feet, used on some gas and water bills.
In practice: A customer checks the CCF unit before comparing two utility bills.
For gas, energy content varies. For water, 1 CCF is approximately 748 U.S. gallons.
CCGT — Combined-cycle gas turbine
Generation, storage & electrification · Technical term · Electric power — A generating arrangement that combines gas turbines with a steam cycle using recovered exhaust heat.
In practice: A CCGT plant recovers turbine exhaust energy in an HRSG.
CCL — Contaminant Candidate List
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — EPA's list of unregulated drinking-water contaminants considered for future regulatory evaluation.
In practice: An analyst reviews a CCL as part of emerging-contaminant planning.
CCR — Consumer confidence report
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A drinking-water quality report provided by community water systems under the applicable requirements.
In practice: A customer reads the annual CCR to understand reported water quality.
CCR also means coal combustion residuals in power-generation environmental work.
CCR — Coal combustion residuals
Environmental management & emissions · Technical term · Cross-utility — Materials remaining from coal combustion, including ash and other specified residuals.
In practice: A power plant manages CCR under applicable waste and water requirements.
In drinking-water communications, CCR means consumer confidence report.
CCT — Corrosion control treatment
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — Treatment designed to reduce the release of metals such as lead and copper into drinking water.
In practice: A utility evaluates CCT under the applicable regulatory process.
CCTV — Closed-circuit television
Wastewater treatment & resource recovery · Technical term · Wastewater — Camera inspection technology used to document the condition of sewers and other utility assets.
In practice: A sewer crew records a CCTV inspection of a pipe segment.
CDD — Cooling degree days
Natural gas & pipeline systems · Technical term · Natural gas — A weather measure of how far average temperatures exceed a selected base temperature over time.
In practice: An analyst uses CDD to compare summer electricity demand.
CEMS — Continuous emissions monitoring system
Environmental management & emissions · Technical term · Cross-utility — Instruments and supporting systems that continuously measure and report specified emissions parameters.
In practice: A plant reviews CEMS quality-assurance records.
CES — Clean energy standard
Markets, rates & planning · Market or planning term · U.S. utility markets — A policy requiring a specified amount or share of qualifying clean electricity.
In practice: A resource plan identifies technologies eligible under its CES.
Eligibility and accounting rules are jurisdiction-specific.
CFS — Cubic feet per second
Units, quantities & symbols · Unit or symbol · Cross-utility — A volumetric flow-rate unit used for streams, drainage, and utility hydraulics.
In practice: A drainage study states peak flow in CFS.
CH4 — Methane
Environmental management & emissions · Chemical symbol · Cross-utility — The main component of natural gas and a greenhouse gas.
In practice: A gas-system emissions inventory tracks CH4 releases.
CHP — Combined heat and power
Generation, storage & electrification · Technical term · Electric power — Production of electricity and useful thermal energy from the same energy input.
In practice: A wastewater plant uses CHP to generate power and digester heat.
Also called cogeneration; useful heat recovery distinguishes it from electricity-only generation.
CIM — Common Information Model
Controls, communications & cybersecurity · Technical term · Cross-utility — A shared information model used in electric-utility data exchange and integration standards.
In practice: An integration team maps network assets to CIM concepts.
CIP — Clean-in-place
Drinking water & distribution · Technical term · Drinking water — Cleaning installed equipment internally without routine disassembly, following its designed cleaning process.
In practice: A membrane plant schedules a CIP cycle.
CIP also means capital improvement plan and critical infrastructure protection.
CIP — Critical Infrastructure Protection
Controls, communications & cybersecurity · Technical term · Cross-utility — A label used for the NERC standards family addressing specified security requirements for bulk-system cyber and physical assets.
In practice: A utility reviews which NERC CIP requirements apply to its assets.
Applicability depends on the specific standards and asset classifications; not every utility device is in scope.
CIP — Capital improvement plan
Asset management & field projects · Technical term · Cross-utility — A prioritized plan for infrastructure investments over a defined period.
In practice: A water utility's CIP schedules main replacements and plant upgrades.
Some organizations expand CIP as capital improvement program.
CIPP — Cured-in-place pipe
Asset management & field projects · Technical term · Cross-utility — A trenchless rehabilitation method forming a cured lining inside an existing pipe.
In practice: A sewer renewal project evaluates CIPP suitability.
CIS — Close-interval survey
Natural gas & pipeline systems · Technical term · Natural gas — A closely spaced survey of pipeline-to-soil potentials used in corrosion assessment.
In practice: An integrity team reviews CIS readings along a pipeline route.
CIS — Customer information system
Metering, billing & customer service · Technical term · Cross-utility — Software managing utility customer accounts, service information, and often billing processes.
In practice: The CIS links a customer account to its service agreement.
Gas integrity teams also use CIS for close-interval survey.
CIU — Categorical industrial user
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — An industrial user subject to categorical pretreatment standards.
In practice: An industrial facility checks whether it is a CIU.
CMMS — Computerized maintenance management system
Asset management & field projects · Technical term · Cross-utility — Software for managing maintenance work, asset history, and associated resources.
In practice: A crew closes a work order in the CMMS after completing an inspection.
CMOM — Capacity, management, operation, and maintenance
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A framework for managing sanitary sewer collection-system performance.
In practice: A utility assesses its collection system using CMOM principles.
CNG — Compressed natural gas
Natural gas & pipeline systems · Technical term · Natural gas — Natural gas stored at elevated pressure, commonly for vehicle fuel or specialized transport.
In practice: A fleet depot includes CNG fueling equipment.
CO — Carbon monoxide
Safety & emergency management · Chemical symbol · Cross-utility — A toxic gas produced by incomplete combustion and other processes.
In practice: A hazard assessment addresses CO exposure from combustion equipment.
CO2 — Carbon dioxide
Environmental management & emissions · Chemical symbol · Cross-utility — A gas produced by combustion and other processes, and a major greenhouse gas.
In practice: A plant reports CO2 emissions under the applicable program.
CO2e — Carbon dioxide equivalent
Environmental management & emissions · Chemical symbol · Cross-utility — A common basis expressing greenhouse-gas quantities using specified global-warming-potential factors.
In practice: An emissions report states its CO2e methodology and time horizon.
Different assessment methods and time horizons can produce different values.
COD — Chemical oxygen demand
Wastewater treatment & resource recovery · Technical term · Wastewater — An oxygen-equivalent measure of material oxidized under a specified chemical test method.
In practice: An operator uses COD trends to identify changing wastewater strength.
COD and BOD values are not interchangeable.
COOP — Continuity of operations
Safety & emergency management · Safety term · Cross-utility — Planning and capabilities for continuing essential functions during disruption.
In practice: A utility's COOP plan identifies alternate facilities and essential roles.
COS — Cost of service
Markets, rates & planning · Market or planning term · U.S. utility markets — The costs assigned to providing regulated service, commonly used to develop revenue requirements and rates.
In practice: A COS study allocates costs among customer classes.
COU — Consumer-owned utility
U.S. agencies & organizations · Organization · U.S. specific — A utility owned by the consumers or communities it serves, commonly through public or cooperative structures.
In practice: A study groups municipal systems and cooperatives as COUs.
CP — Cathodic protection
Natural gas & pipeline systems · Technical term · Natural gas — A corrosion-control method that makes the protected metal the cathode of an electrochemical cell.
In practice: A buried steel main has CP facilities and monitoring records.
CPCN — Certificate of public convenience and necessity
Markets, rates & planning · Market or planning term · U.S. utility markets — An authorization used by regulators for specified utility services or facilities.
In practice: A project team reviews whether its proposed facility requires a CPCN.
The issuing authority, scope, and requirements vary by jurisdiction.
CPP — Critical peak pricing
Markets, rates & planning · Market or planning term · U.S. utility markets — A rate design using higher prices during designated critical periods.
In practice: A utility notifies enrolled customers before a CPP event.
CPR — Certified payroll report
Workforce, time & administration · Workforce term · Cross-utility — A payroll report and certification used for covered prevailing-wage work.
In practice: A contractor prepares a CPR for a covered utility construction project.
The required form, submission method, and coverage depend on the contract and jurisdiction.
CRM — Customer relationship management
Metering, billing & customer service · Technical term · Cross-utility — Processes or software for managing customer interactions and service cases.
In practice: A contact-center agent logs an inquiry in the CRM.
CRR — Congestion revenue right
Markets, rates & planning · Market or planning term · U.S. utility markets — A market-specific financial right associated with transmission congestion revenues, used in regions such as California and Texas.
In practice: A CAISO participant reviews its CRR settlement.
CSO — Combined sewer overflow
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A discharge from a combined sewer system when its capacity is exceeded under specified conditions.
In practice: Wet weather can cause a CSO from a combined system.
CSP — Concentrating solar power
Generation, storage & electrification · Technical term · Electric power — Solar thermal generation using mirrors to concentrate sunlight and produce useful heat.
In practice: A CSP plant uses collected heat to run a turbine.
CT — Current transformer
Electric equipment & distribution · Technical term · Electric power — An instrument transformer that produces a scaled current for metering or protection.
In practice: A meter installation specifies the CT ratio.
CT also means combustion turbine or disinfectant concentration multiplied by contact time.
CT — Combustion turbine
Generation, storage & electrification · Technical term · Electric power — A turbine that uses hot combustion gases to drive a shaft and generate power.
In practice: A peaking plant starts a CT during high demand.
Do not confuse this CT with an instrument current transformer.
CT — Disinfectant concentration multiplied by contact time
Drinking water & distribution · Technical term · Drinking water — A disinfection measure combining residual disinfectant concentration and effective contact time under the specified method.
In practice: An operator evaluates CT using the applicable disinfectant, temperature, pH, and target organism.
CT is not a universal dose or a standalone operating instruction.
CVR — Conservation voltage reduction
Electric equipment & distribution · Technical term · Electric power — Reducing distribution voltage within allowed limits to reduce some customer loads and energy consumption.
In practice: A pilot measures the energy effect of CVR on selected feeders.
CWA — Clean Water Act
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — The federal law providing a major framework for protecting U.S. surface-water quality.
In practice: A discharge permit is issued under the CWA framework.
CWIP — Construction work in progress
Markets, rates & planning · Market or planning term · U.S. utility markets — The accounting value of utility construction that has not yet entered service.
In practice: A rate filing separately identifies CWIP balances.
CWS — Community water system
Drinking water & distribution · Technical term · Drinking water — A public water system serving the same population year-round.
In practice: A town's residential water network operates as a CWS.
CWSRF — Clean Water State Revolving Fund
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A state-administered funding framework supporting eligible water-quality infrastructure and projects.
In practice: A wastewater utility evaluates CWSRF financing.
DA — Distribution automation
Electric equipment & distribution · Technical term · Electric power — Use of sensing, communications, and control to automate distribution-system functions.
In practice: DA equipment reports feeder conditions and supports remote switching.
DADS — Demand Response Availability Data System
Grid operations & reliability · Technical term · Electric power — NERC's system for collecting information about demand-response availability and performance.
In practice: A program administrator reviews DADS reporting requirements.
DAF — Dissolved air flotation
Wastewater treatment & resource recovery · Technical term · Wastewater — A separation process using fine bubbles to float selected suspended material for removal.
In practice: A solids-handling process uses DAF for thickening.
DAM — Day-ahead market
Markets, rates & planning · Market or planning term · U.S. utility markets — A market that schedules and prices electricity for the following operating day.
In practice: A supplier submits DAM offers before the deadline.
DBP — Disinfection byproduct
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A compound formed when a disinfectant reacts with materials in water.
In practice: A treatment study assesses DBP formation alongside microbial protection.
DBRA — Davis-Bacon and Related Acts
Workforce, time & administration · Workforce term · Cross-utility — The federal prevailing-wage framework applying to covered construction contracts and related federally assisted work.
In practice: A covered utility construction project reviews DBRA wage and reporting obligations.
DC — Direct current
Generation, storage & electrification · Technical term · Electric power — Electric current that flows in one direction.
In practice: A battery stores energy that is delivered electrically as DC.
DCFC — Direct-current fast charging
Generation, storage & electrification · Technical term · Electric power — Vehicle charging that delivers DC power through off-board conversion equipment.
In practice: A DCFC site may require a larger utility service connection.
DCS — Distributed control system
Controls, communications & cybersecurity · Technical term · Cross-utility — A control architecture distributing control functions among connected controllers, typically within a process facility.
In practice: A generating plant uses a DCS for process control.
DCVA — Double check valve assembly
Drinking water & distribution · Technical term · Drinking water — A backflow-prevention assembly using two independently acting check valves and associated components.
In practice: A cross-connection survey documents an approved DCVA installation.
DCVG — Direct-current voltage gradient
Natural gas & pipeline systems · Technical term · Natural gas — A survey technique using voltage gradients in the ground to locate and assess coating defects.
In practice: A corrosion assessment combines DCVG results with other evidence.
DER — Distributed energy resource
Generation, storage & electrification · Technical term · Electric power — A generation, storage, or flexible-load resource connected at distribution level or on customer premises.
In practice: A utility studies how new DER affects a feeder.
DERMS — Distributed energy resource management system
Generation, storage & electrification · Technical term · Electric power — Software that monitors and coordinates distributed resources subject to network and resource constraints.
In practice: DERMS manages a fleet of flexible devices across feeders.
DG — Distributed generation
Generation, storage & electrification · Technical term · Electric power — Electricity generation located close to the load it serves, often connected to a distribution network.
In practice: A rooftop solar system is a form of DG.
DIMP — Distribution integrity management program
Natural gas & pipeline systems · Technical term · Natural gas — The integrity-management framework applied to regulated gas distribution systems.
In practice: A gas utility evaluates threats and performance measures through DIMP.
DMA — District metered area
Drinking water & distribution · Technical term · Drinking water — A defined part of a water network with metered flows used to monitor demand and losses.
In practice: Night-flow analysis in a DMA helps identify unusual water use.
DMR — Discharge monitoring report
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A report of discharge monitoring results required under an applicable permit.
In practice: A facility submits its DMR for the reporting period.
DMS — Distribution management system
Electric equipment & distribution · Technical term · Electric power — Software that supports analysis and operation of an electric distribution network.
In practice: The DMS helps evaluate a feeder switching plan.
DMZ — Demilitarized zone
Controls, communications & cybersecurity · Technical term · Cross-utility — A network segment placed between security zones to mediate approved communications.
In practice: A utility places selected data-transfer services in a DMZ.
DNP3 — Distributed Network Protocol 3
Controls, communications & cybersecurity · Technical term · Cross-utility — A communications protocol widely used for utility telemetry and control.
In practice: A substation gateway exchanges points using DNP3.
DO — Dissolved oxygen
Wastewater treatment & resource recovery · Technical term · Wastewater — Oxygen dissolved in water, commonly reported as a concentration.
In practice: A biological treatment process monitors DO in an aeration basin.
DOC — Dissolved organic carbon
Drinking water & distribution · Technical term · Drinking water — The organic carbon fraction classified as dissolved by the specified analytical method.
In practice: A treatment study compares DOC before and after a process.
DOD — Depth of discharge
Generation, storage & electrification · Technical term · Electric power — The fraction of battery capacity removed during discharge relative to a stated reference capacity.
In practice: A battery warranty specifies a cycling assumption using DOD.
DOE — Department of Energy
U.S. agencies & organizations · Organization · U.S. specific — The U.S. federal department responsible for national energy programs, research, and related missions.
In practice: A utility reviews a DOE grid-modernization resource.
U.S. Department of Energy in this database.
DOL — Department of Labor
Workforce, time & administration · Workforce term · Cross-utility — The U.S. federal department administering labor and employment programs through its agencies.
In practice: An employer consults DOL guidance on covered pay requirements.
DP — Distribution Provider
Grid operations & reliability · Technical term · Electric power — An entity providing and operating the distribution connection between the transmission system and end-use customers.
In practice: The DP coordinates protective-device settings at a delivery point.
DPR — Direct potable reuse
Wastewater treatment & resource recovery · Technical term · Wastewater — Potable reuse without the environmental buffer used in indirect potable reuse, under the applicable framework.
In practice: A utility studies DPR within its state regulatory process.
Treatment barriers and approvals are jurisdiction- and project-specific.
DR — Demand response
Markets, rates & planning · Market or planning term · U.S. utility markets — Changes in customer electricity use in response to prices, incentives, or reliability signals.
In practice: A customer reduces load during a DR event.
DR — Dimension ratio
Natural gas & pipeline systems · Technical term · Natural gas — The ratio of a pipe's specified outside diameter to its specified minimum wall thickness.
In practice: A pipe schedule identifies the material and DR together.
This DR concerns pipe geometry, not electric demand response.
DSM — Demand-side management
Markets, rates & planning · Market or planning term · U.S. utility markets — Utility activities that influence customer demand through efficiency, load management, and related measures.
In practice: A DSM portfolio includes efficiency programs and flexible-load measures.
Dth — Dekatherm
Units, quantities & symbols · Unit or symbol · Cross-utility — An energy unit equal to ten therms or one million Btu.
In practice: A transportation statement lists scheduled gas in Dth.
Dekatherm;dekatherms
DWSRF — Drinking Water State Revolving Fund
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A state-administered funding framework supporting eligible drinking-water infrastructure and related activities.
In practice: A community evaluates DWSRF assistance for an eligible water project.
E-ISAC — Electricity Information Sharing and Analysis Center
Controls, communications & cybersecurity · Technical term · Cross-utility — An electricity-sector organization supporting sharing and analysis of security information.
In practice: A utility security team uses E-ISAC resources.
EACMS — Electronic Access Control or Monitoring Systems
Controls, communications & cybersecurity · Technical term · Cross-utility — Systems performing specified electronic access-control or monitoring functions within NERC's defined framework.
In practice: A compliance inventory identifies EACMS supporting a protected environment.
EAM — Enterprise asset management
Asset management & field projects · Technical term · Cross-utility — The coordinated management of assets across their lifecycle, often supported by integrated software.
In practice: An EAM program connects condition, maintenance, cost, and renewal decisions.
EAP — Emergency action plan
Safety & emergency management · Safety term · Cross-utility — A plan describing required employee actions during designated emergencies.
In practice: A site briefing identifies the EAP and assembly arrangements.
EBCT — Empty bed contact time
Drinking water & distribution · Technical term · Drinking water — The nominal contact time calculated from media-bed volume divided by flow rate.
In practice: A GAC design states the selected EBCT.
EBPR — Enhanced biological phosphorus removal
Wastewater treatment & resource recovery · Technical term · Wastewater — A biological process that encourages organisms to remove phosphorus into the solids stream.
In practice: A process design includes EBPR ahead of solids removal.
ECDA — External corrosion direct assessment
Natural gas & pipeline systems · Technical term · Natural gas — A structured assessment approach for evaluating external pipeline corrosion using integrated indirect and direct examinations.
In practice: An integrity plan documents the selected ECDA methodology.
ECHO — Enforcement and Compliance History Online
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — EPA's public system for searching environmental compliance and enforcement information.
In practice: An analyst reviews a facility's ECHO record and its reporting dates.
EE — Energy efficiency
Markets, rates & planning · Market or planning term · U.S. utility markets — Delivering a service with less energy input.
In practice: A motor upgrade is evaluated for its EE benefit.
EFV — Excess flow valve
Natural gas & pipeline systems · Technical term · Natural gas — A device designed to restrict gas flow when it exceeds a specified threshold under operating conditions.
In practice: A service-line record identifies an installed EFV.
EIA — Energy Information Administration
U.S. agencies & organizations · Organization · U.S. specific — The U.S. statistical and analytical agency publishing energy data and analysis.
In practice: An analyst uses EIA data to compare generation trends.
ELCC — Effective load carrying capability
Markets, rates & planning · Performance metric · U.S. utility markets — The additional load a resource can support while maintaining a specified reliability level.
In practice: An adequacy study estimates a storage resource's ELCC.
ELCC depends on the wider resource mix, weather, and study assumptions.
EMS — Energy management system
Electric equipment & distribution · Technical term · Electric power — Control-center software for monitoring, analyzing, and managing a power system.
In practice: The EMS supports state estimation and generation dispatch.
EMS can mean other systems in environmental or building-management contexts.
EMS — Environmental management system
Environmental management & emissions · Technical term · Cross-utility — A structured approach for managing an organization's environmental responsibilities and objectives.
In practice: A utility's EMS tracks environmental procedures and corrective actions.
Grid control centers use EMS for energy management system.
EOC — Emergency operations center
Safety & emergency management · Safety term · Cross-utility — A physical or virtual location supporting coordinated incident information, resources, and decisions.
In practice: An EOC coordinates support during a widespread outage.
EPA — Environmental Protection Agency
U.S. agencies & organizations · Organization · U.S. specific — The U.S. federal agency administering major environmental and drinking-water programs.
In practice: A water utility consults EPA drinking-water resources.
EPZ — Equipotential zone
Safety & emergency management · Safety term · Cross-utility — An area arranged to reduce hazardous voltage differences affecting workers under a designed protective-grounding approach.
In practice: A qualified electrical work plan addresses the EPZ.
This definition is not a grounding design or work instruction.
ERCOT — Electric Reliability Council of Texas
U.S. agencies & organizations · Organization · U.S. specific — The organization operating the ERCOT power grid and administering its wholesale market.
In practice: A Texas market participant follows ERCOT protocols.
ERCOT does not cover every part of Texas.
ERP — Emergency response plan
Safety & emergency management · Safety term · Cross-utility — An organization's plan for responding to specified emergencies.
In practice: A water utility reviews its ERP roles and communications.
Business software documents may instead use ERP for enterprise resource planning.
ERP — Enterprise resource planning
Workforce, time & administration · Workforce term · Cross-utility — Integrated business software managing functions such as finance, procurement, and human resources.
In practice: An ERP integration exchanges approved work and cost data.
Emergency planning uses ERP for emergency response plan.
ERW — Electric resistance welded
Natural gas & pipeline systems · Technical term · Natural gas — A pipe-manufacturing description referring to a longitudinal seam produced by electric-resistance welding.
In practice: The material record identifies the pipe as ERW.
ESP — Electronic Security Perimeter
Controls, communications & cybersecurity · Technical term · Cross-utility — The logical border around specified cyber systems under the applicable NERC definition.
In practice: A compliance diagram documents the ESP and relevant access points.
ESS — Energy storage system
Generation, storage & electrification · Technical term · Electric power — Equipment that stores energy for later use through batteries or other storage technologies.
In practice: A planning study compares different ESS technologies.
EUE — Expected unserved energy
Markets, rates & planning · Performance metric · U.S. utility markets — The expected quantity of energy demand that cannot be served in a reliability assessment.
In practice: Two portfolios with similar event frequencies can have different EUE.
EV — Electric vehicle
Generation, storage & electrification · Technical term · Electric power — A vehicle powered partly or entirely by electricity stored on board.
In practice: A fleet electrification plan estimates EV charging demand.
EVSE — Electric vehicle supply equipment
Generation, storage & electrification · Technical term · Electric power — Equipment that safely supplies electricity for vehicle charging.
In practice: The depot plan includes EVSE locations and service capacity.
F/M — Food-to-microorganism ratio
Wastewater treatment & resource recovery · Technical term · Wastewater — The organic loading rate relative to the selected biological-solids inventory.
In practice: An activated-sludge review calculates F/M using a stated BOD and biomass basis.
FACTS — Flexible AC transmission systems
Electric equipment & distribution · Technical term · Electric power — Power-electronic technologies that help control AC transmission characteristics.
In practice: A planning study evaluates a FACTS device for voltage support.
FERC — Federal Energy Regulatory Commission
U.S. agencies & organizations · Organization · U.S. specific — The federal commission overseeing specified interstate energy activities and wholesale electricity matters.
In practice: A project checks whether a proposed transaction requires FERC action.
FGD — Flue gas desulfurization
Environmental management & emissions · Technical term · Cross-utility — Processes that remove sulfur dioxide from combustion exhaust.
In practice: A coal plant operates FGD equipment to control sulfur emissions.
FLISR — Fault location, isolation, and service restoration
Electric equipment & distribution · Technical term · Electric power — Coordinated functions that identify a faulted section, isolate it, and restore eligible healthy sections.
In practice: A feeder automation project includes FLISR functionality.
Restoration depends on available topology, equipment ratings, and operating limits.
FLSA — Fair Labor Standards Act
Workforce, time & administration · Workforce term · Cross-utility — The federal law governing minimum wage, overtime, and other employment standards for covered work.
In practice: A payroll team evaluates FLSA requirements alongside other applicable rules.
FMEA — Failure modes and effects analysis
Asset management & field projects · Technical term · Cross-utility — A systematic assessment of how components can fail and what those failures would cause.
In practice: A project uses FMEA to prioritize design and maintenance actions.
FOG — Fats, oils, and grease
Wastewater treatment & resource recovery · Technical term · Wastewater — Materials from food and other sources that can obstruct sewers or interfere with wastewater treatment.
In practice: A utility's FOG program addresses grease discharges from food businesses.
FPA — Federal Power Act
Markets, rates & planning · Market or planning term · U.S. utility markets — A federal statute underlying major portions of FERC's electricity authority.
In practice: A filing identifies its authority under the FPA.
FTE — Full-time equivalent
Workforce, time & administration · Workforce term · Cross-utility — A staffing measure converting labor hours or workload into equivalent full-time positions under a stated convention.
In practice: A utility compares staffing needs in FTEs using its defined annual-hour basis.
FTE is not always the same as employee headcount.
FTM — Front of the meter
Generation, storage & electrification · Technical term · Electric power — Located on the grid side of a customer's retail billing meter, commonly serving utility or market functions.
In practice: A FTM battery participates under the relevant interconnection and market arrangements.
FTR — Financial transmission right
Markets, rates & planning · Market or planning term · U.S. utility markets — A financial instrument used in some markets to address specified congestion-price differences.
In practice: A participant holds an FTR between two pricing locations.
An FTR is not a physical reservation of transmission capacity; market rules govern payouts and risks.
FTTH — Fiber to the home
Municipal broadband & communications · Technical term · Municipal broadband — A network architecture bringing optical fiber to individual homes.
In practice: A municipal utility evaluates FTTH service in its territory.
FTTP — Fiber to the premises
Municipal broadband & communications · Technical term · Municipal broadband — A network architecture bringing optical fiber to customer premises.
In practice: A utility's FTTP project serves homes and businesses.
G&T — Generation and transmission cooperative
U.S. agencies & organizations · Organization · U.S. specific — A cooperative providing wholesale power and related services to member distribution cooperatives.
In practice: A distribution cooperative purchases power through its G&T.
GAC — Granular activated carbon
Drinking water & distribution · Technical term · Drinking water — Granular adsorptive media used to remove certain contaminants, tastes, odors, or organic compounds.
In practice: A WTP monitors breakthrough in a GAC contactor.
GADS — Generating Availability Data System
Grid operations & reliability · Technical term · Electric power — NERC's system for collecting generating-unit availability and performance information.
In practice: A plant reports qualifying outage events through GADS.
gal — Gallon
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of volume; utility examples in this database use the U.S. liquid gallon.
In practice: A tank record states its usable volume in U.S. gal.
The U.S. liquid gallon differs from the Imperial gallon.
Gbps — Gigabits per second
Municipal broadband & communications · Unit or symbol · Municipal broadband — A data-transfer rate measured in billions of bits each second.
In practice: A network backbone has a capacity specified in Gbps.
GHG — Greenhouse gas
Environmental management & emissions · Technical term · Cross-utility — A gas that absorbs and emits infrared radiation, contributing to the greenhouse effect.
In practice: A utility inventory separately accounts for different GHGs.
GHS — Globally Harmonized System of Classification and Labelling of Chemicals
Safety & emergency management · Safety term · Cross-utility — The international framework informing standardized chemical hazard classification and communication.
In practice: A chemical label uses GHS-aligned pictograms under the applicable rules.
GI — Green infrastructure
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — Vegetated, soil-based, or related systems that manage stormwater and provide other benefits.
In practice: A stormwater project evaluates GI for local runoff control.
GIS — Gas-insulated switchgear
Electric equipment & distribution · Technical term · Electric power — Switchgear whose energized components are enclosed in an insulating gas system.
In practice: A substation design compares GIS with an air-insulated arrangement.
GIS also means geographic information system; the engineering discipline matters.
GIS — Geographic information system
Controls, communications & cybersecurity · Technical term · Cross-utility — Software and data that organize assets and other information by location.
In practice: A utility GIS maps mains, poles, valves, and service connections.
Substation equipment documents also use GIS for gas-insulated switchgear.
GNSS — Global navigation satellite system
Controls, communications & cybersecurity · Technical term · Cross-utility — A general term for satellite constellations providing positioning, navigation, and timing services.
In practice: Survey equipment uses GNSS signals for asset mapping.
GO — Generator Owner
Grid operations & reliability · Technical term · Electric power — The entity that owns and maintains generating facilities.
In practice: The GO documents generator equipment characteristics.
GOOSE — Generic Object Oriented Substation Event
Controls, communications & cybersecurity · Technical term · Cross-utility — An IEC 61850 messaging mechanism used for time-sensitive substation event information.
In practice: A substation design specifies GOOSE messaging among compatible devices.
GOP — Generator Operator
Grid operations & reliability · Technical term · Electric power — The entity that operates generating facilities and performs their operating functions.
In practice: The GOP communicates a unit outage to the control center.
GPM — Gallons per minute
Units, quantities & symbols · Unit or symbol · Cross-utility — A volumetric flow rate expressed here in U.S. liquid gallons each minute.
In practice: A pump duty point specifies flow in GPM.
GPS — Global Positioning System
Controls, communications & cybersecurity · Technical term · Cross-utility — The U.S. satellite-based positioning, navigation, and timing system.
In practice: A field team records an asset location using GPS equipment.
GW — Gigawatt
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of power equal to one thousand megawatts.
In practice: A regional forecast expresses peak demand in GW.
GWh — Gigawatt-hour
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of energy equal to one million kilowatt-hours.
In practice: A utility reports annual purchased energy in GWh.
GWR — Ground Water Rule
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The federal drinking-water rule addressing microbial protection for groundwater systems.
In practice: A groundwater utility reviews GWR monitoring and response provisions.
H2S — Hydrogen sulfide
Safety & emergency management · Chemical symbol · Cross-utility — A toxic, flammable gas that can occur in wastewater, gas, and other utility environments.
In practice: A hazard assessment considers possible H2S exposure at a facility.
Do not rely on smell to detect hazardous concentrations.
HAA5 — Haloacetic acids (five)
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The regulated group of five specified haloacetic acid disinfection byproducts.
In practice: A water-quality report lists the HAA5 result.
HAA-5
HAB — Harmful algal bloom
Drinking water & distribution · Technical term · Drinking water — A bloom of algae or cyanobacteria that can harm water quality, ecosystems, or health.
In practice: A source-water program monitors for HAB conditions.
HAN — Home area network
Metering, billing & customer service · Technical term · Cross-utility — A local communications network connecting compatible devices within a home.
In practice: A smart-meter program uses a HAN for customer energy information.
HCA — High consequence area
Natural gas & pipeline systems · Technical term · Natural gas — An area identified under pipeline regulations where a release could have especially serious consequences.
In practice: An integrity program identifies pipeline segments associated with HCAs.
Gas and hazardous-liquid HCA definitions differ.
HDD — Heating degree days
Natural gas & pipeline systems · Technical term · Natural gas — A weather measure of how far average temperatures fall below a selected base temperature over time.
In practice: A utility uses HDD to normalize winter gas demand.
State the base temperature and time period. HDD also means horizontal directional drilling.
HDD — Horizontal directional drilling
Asset management & field projects · Technical term · Cross-utility — A trenchless construction method using a guided bore to install utilities.
In practice: A crossing design evaluates HDD feasibility.
Gas-demand forecasts use HDD for heating degree days.
HDPE — High-density polyethylene
Natural gas & pipeline systems · Technical term · Natural gas — A polyethylene material class used in utility piping and other products.
In practice: A water project evaluates HDPE pipe for a specified installation.
HMI — Human-machine interface
Controls, communications & cybersecurity · Technical term · Cross-utility — The display and controls through which an operator interacts with a machine or control system.
In practice: An HMI shows pump alarms and process measurements.
HPC — Heterotrophic plate count
Drinking water & distribution · Technical term · Drinking water — A culture-based measure of selected heterotrophic microorganisms under specified test conditions.
In practice: A distribution study includes HPC results as one water-quality indicator.
HPC is not a direct count of all pathogens.
HRSG — Heat recovery steam generator
Generation, storage & electrification · Technical term · Electric power — Equipment that uses a hot exhaust stream to produce steam.
In practice: The HRSG supplies steam to the combined-cycle steam turbine.
HRT — Hydraulic retention time
Wastewater treatment & resource recovery · Technical term · Wastewater — Nominal time water remains in a defined process volume at a stated flow.
In practice: A process design lists HRT for the reactor.
HVDC — High-voltage direct current
Electric equipment & distribution · Technical term · Electric power — Transmission technology that moves bulk electric power as direct current between converter stations.
In practice: An HVDC link connects two power-system areas.
Hz — Hertz
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of frequency equal to one cycle per second.
In practice: The nominal frequency of the U.S. interconnected AC power system is 60 Hz.
I/I — Infiltration and inflow
Wastewater treatment & resource recovery · Technical term · Wastewater — Unwanted water entering a sanitary sewer through groundwater leakage or direct stormwater connections.
In practice: A wet-weather investigation separates I/I from ordinary sanitary flow.
IBR — Inverter-based resource
Generation, storage & electrification · Technical term · Electric power — A generating or storage resource that connects to the grid through a power-electronic inverter.
In practice: A study evaluates how an IBR responds to voltage disturbances.
ICCP — Inter-Control Center Communications Protocol
Controls, communications & cybersecurity · Technical term · Cross-utility — A protocol used for exchanging power-system information between control centers.
In practice: Two operators exchange approved data through ICCP.
ICDA — Internal corrosion direct assessment
Natural gas & pipeline systems · Technical term · Natural gas — A structured method for evaluating internal corrosion risk in applicable pipelines.
In practice: An operator checks whether ICDA is appropriate for the segment and service.
ICS — Industrial control system
Controls, communications & cybersecurity · Technical term · Cross-utility — An umbrella term for systems that monitor and control industrial processes.
In practice: A water plant's ICS includes controllers, operator interfaces, and communications.
Emergency-management documents use ICS for incident command system.
ICS — Incident command system
Safety & emergency management · Safety term · Cross-utility — A standardized structure for managing incidents through defined roles and coordination.
In practice: A utility coordinates storm response using an ICS structure.
In automation documents, ICS means industrial control system.
IDLH — Immediately dangerous to life or health
Safety & emergency management · Safety term · Cross-utility — A term describing atmospheric conditions that pose an immediate severe threat or impair escape.
In practice: A hazard evaluation considers whether IDLH conditions could exist.
IDS — Intrusion detection system
Controls, communications & cybersecurity · Technical term · Cross-utility — A system that identifies and reports potentially malicious or policy-violating activity.
In practice: An OT monitoring program reviews alerts from an IDS.
IED — Intelligent electronic device
Electric equipment & distribution · Technical term · Electric power — A microprocessor-based device that performs protection, monitoring, metering, or control functions.
In practice: A substation IED records a fault and communicates relay status.
IFAS — Integrated fixed-film activated sludge
Wastewater treatment & resource recovery · Technical term · Wastewater — A process combining attached biological growth with suspended activated sludge.
In practice: An IFAS retrofit adds media to an existing biological process.
ILI — In-line inspection
Natural gas & pipeline systems · Technical term · Natural gas — Inspection using an instrumented tool that travels inside a pipeline.
In practice: An ILI run collects data on selected pipe-wall conditions.
ILI — Infrastructure leakage index
Drinking water & distribution · Technical term · Drinking water — A water-loss indicator comparing current annual real losses with estimated unavoidable annual real losses.
In practice: A utility reviews ILI alongside pressure and system characteristics.
This ILI is a water-loss metric; gas pipelines use ILI for in-line inspection.
IMP — Integrity management program
Natural gas & pipeline systems · Technical term · Natural gas — A structured program for identifying, assessing, and managing pipeline integrity risks.
In practice: An operator updates its IMP after reviewing inspection results.
IOU — Investor-owned utility
U.S. agencies & organizations · Organization · U.S. specific — A utility owned by private investors or shareholders.
In practice: An industry comparison distinguishes an IOU from a cooperative.
IPP — Independent power producer
Markets, rates & planning · Market or planning term · U.S. utility markets — A nonutility producer that develops or operates generation for sale to others.
In practice: An IPP sells output under a PPA or through a market.
IPR — Indirect potable reuse
Wastewater treatment & resource recovery · Technical term · Wastewater — Potable reuse that includes an environmental buffer before water is treated or supplied for drinking.
In practice: A reuse concept includes reservoir augmentation as an IPR pathway.
IPS — Intrusion prevention system
Controls, communications & cybersecurity · Technical term · Cross-utility — A system capable of detecting and blocking selected traffic or activity.
In practice: A security design evaluates IPS behavior against process-availability needs.
IROL — Interconnection Reliability Operating Limit
Grid operations & reliability · Technical term · Electric power — A system operating limit whose violation could lead to instability, uncontrolled separation, or cascading outages.
In practice: The control room responds under its procedures to an IROL exceedance.
IRP — Integrated resource plan
Markets, rates & planning · Market or planning term · U.S. utility markets — A long-term plan comparing supply, demand-side, and other options for meeting utility needs.
In practice: An IRP evaluates generation, storage, efficiency, and demand response.
ISO — Independent system operator
Markets, rates & planning · Market or planning term · U.S. utility markets — An independent organization that operates a power system and, in many regions, administers wholesale markets.
In practice: A market participant submits offers to the ISO.
In standards documents, ISO can instead refer to the International Organization for Standardization.
ISO-NE — ISO New England
U.S. agencies & organizations · Organization · U.S. specific — The organization operating the New England bulk power system and wholesale electricity markets.
In practice: A participant reviews ISO-NE market rules.
ISP — Internet service provider
Municipal broadband & communications · Technical term · Municipal broadband — An organization providing internet connectivity services.
In practice: A municipal network operates as an ISP or partners with one.
IT — Information technology
Controls, communications & cybersecurity · Technical term · Cross-utility — Systems used to process, store, and communicate information.
In practice: An integration project connects approved IT and OT systems.
IVR — Interactive voice response
Metering, billing & customer service · Technical term · Cross-utility — An automated telephone interface that accepts caller input and delivers information or routing.
In practice: An IVR lets a customer report an outage.
IX — Ion exchange
Drinking water & distribution · Technical term · Drinking water — A treatment process that exchanges ions in water with ions associated with a treatment medium.
In practice: A system uses IX resin to remove a targeted dissolved constituent.
JHA — Job hazard analysis
Safety & emergency management · Safety term · Cross-utility — A structured review of job steps, hazards, and protective measures.
In practice: A crew reviews the JHA before its assigned work.
JSA — Job safety analysis
Safety & emergency management · Safety term · Cross-utility — A structured review of task hazards and controls, often used similarly to job hazard analysis.
In practice: A briefing references the current JSA.
KPI — Key performance indicator
Asset management & field projects · Technical term · Cross-utility — A selected metric used to track progress toward an operational or business objective.
In practice: A maintenance KPI tracks completed planned work against the schedule.
kV — Kilovolt
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of electric potential equal to one thousand volts.
In practice: A line drawing identifies the circuit voltage in kV.
kVA — Kilovolt-ampere
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of apparent electrical power equal to one thousand volt-amperes.
In practice: A transformer nameplate lists its rating in kVA.
kVAR — Kilovolt-ampere reactive
Units, quantities & symbols · Unit or symbol · Cross-utility — A reactive-power unit equal to one thousand VAR.
In practice: A capacitor bank's rating is expressed in kVAR.
kvar;kVAr
kW — Kilowatt
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of power equal to one thousand watts.
In practice: A device drawing 2 kW continuously for 3 hours uses 6 kWh.
Power is a rate; energy accumulates over time.
kWh — Kilowatt-hour
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of energy equal to one kilowatt sustained for one hour.
In practice: An electricity bill lists monthly energy use in kWh.
kW/h is not a substitute notation for kWh.
LAN — Local area network
Metering, billing & customer service · Technical term · Cross-utility — A communications network serving a limited site or local area.
In practice: A treatment plant's control network includes a LAN.
LBMP — Locational-based marginal price
Markets, rates & planning · Market or planning term · U.S. utility markets — NYISO's term for location-specific marginal electricity pricing.
In practice: A New York settlement statement lists hourly LBMP values.
LCOE — Levelized cost of energy
Markets, rates & planning · Market or planning term · U.S. utility markets — A discounted lifetime cost measure per unit of energy under stated cost, output, and financing assumptions.
In practice: A study reports LCOE alongside reliability and integration considerations.
LCOE alone does not establish a resource's system value or retail price.
LCOH — Levelized cost of heat
Markets, rates & planning · Market or planning term · U.S. utility markets — A lifetime cost measure per unit of useful heat delivered under stated assumptions.
In practice: A district-energy study compares heat supply options using LCOH.
LCR — Lead and Copper Rule
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The drinking-water rule framework addressing lead and copper, including corrosion control and related duties.
In practice: A utility reviews its LCR compliance program.
LCRI — Lead and Copper Rule Improvements
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — EPA's named improvements to the lead-and-copper regulatory framework.
In practice: A water system reviews the current LCRI requirements and implementation dates.
Consult current EPA materials and the primacy agency for effective requirements and deadlines.
LDAR — Leak detection and repair
Natural gas & pipeline systems · Technical term · Natural gas — A program for locating leaks and managing their repair under the relevant requirements.
In practice: A gas facility tracks findings and repairs in its LDAR program.
LDC — Local distribution company
Natural gas & pipeline systems · Technical term · Natural gas — A utility company delivering natural gas through local distribution networks to customers.
In practice: An LDC forecasts winter demand for homes and businesses.
LEL — Lower explosive limit
Safety & emergency management · Safety term · Cross-utility — The lowest concentration of a gas or vapor in air capable of propagating flame under specified conditions.
In practice: A gas-detection instrument reports a reading as percent of LEL.
Percent LEL is not the same as percent gas by volume; do not use this reference to set entry or response limits.
LFG — Landfill gas
Natural gas & pipeline systems · Technical term · Natural gas — Gas produced by decomposition of landfill waste, commonly containing methane and carbon dioxide.
In practice: A project captures LFG for energy recovery.
LID — Low impact development
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — An approach managing runoff near its source using practices that mimic or preserve natural hydrology.
In practice: A site plan incorporates LID practices where suitable.
LIHEAP — Low Income Home Energy Assistance Program
Metering, billing & customer service · Technical term · Cross-utility — A federally funded program supporting eligible households with home energy needs through administering agencies.
In practice: A customer-service representative directs an applicant to the appropriate LIHEAP agency.
Eligibility, benefits, funding, and application routes vary by administering program.
LMP — Locational marginal price
Markets, rates & planning · Market or planning term · U.S. utility markets — The marginal cost of serving an additional unit of electricity at a particular location, including applicable energy, congestion, and loss components.
In practice: Two locations have different LMPs when transmission is constrained.
Wholesale LMP is not the customer's complete retail electricity rate.
LNG — Liquefied natural gas
Natural gas & pipeline systems · Technical term · Natural gas — Natural gas cooled to a liquid state for storage or transportation.
In practice: A utility uses an LNG facility to supplement peak-period supply.
LOLE — Loss of load expectation
Markets, rates & planning · Performance metric · U.S. utility markets — The expected frequency or duration of periods in which available supply cannot meet demand, using a stated study unit.
In practice: An adequacy study reports LOLE in days per year.
Always check the unit and methodology; different formulations are not automatically comparable.
LOLP — Loss of load probability
Markets, rates & planning · Performance metric · U.S. utility markets — The probability that available supply will be insufficient for demand during a specified interval.
In practice: A model estimates LOLP for a high-demand hour.
LOS — Level of service
Asset management & field projects · Technical term · Cross-utility — A defined service outcome or performance target used to guide asset-management decisions.
In practice: A utility sets LOS targets for reliability and response.
LOTO — Lockout/tagout
Safety & emergency management · Safety term · Cross-utility — Procedures and devices used to control hazardous energy under the applicable work rules.
In practice: A maintenance assignment requires the approved LOTO process.
Electric generation, transmission, and distribution work may be governed by specific energy-control provisions.
LSE — Load-Serving Entity
Grid operations & reliability · Technical term · Electric power — An entity responsible for securing energy and transmission arrangements to serve its customers' electricity demand.
In practice: The LSE forecasts next summer's customer load.
LSL — Lead service line
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A service line containing lead under the applicable inventory or regulatory definition.
In practice: A utility develops an LSL inventory and replacement plan.
LTCP — Long-term control plan
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A plan for addressing combined sewer overflows under the relevant program.
In practice: A combined-sewer utility updates its LTCP project schedule.
MAD — Minimum approach distance
Safety & emergency management · Safety term · Cross-utility — A required separation distance for specified electrical work conditions under the applicable rules.
In practice: A qualified-work plan establishes the applicable MAD.
The distance depends on voltage, exposure, worker qualifications, and governing rules.
MAOP — Maximum allowable operating pressure
Natural gas & pipeline systems · Technical term · Natural gas — The maximum pressure at which a gas pipeline or segment may operate under the applicable regulatory basis.
In practice: A pipeline record identifies the established MAOP.
This glossary does not determine or authorize an operating pressure.
MBBR — Moving bed biofilm reactor
Wastewater treatment & resource recovery · Technical term · Wastewater — A biological process using mobile carriers that support attached microbial growth.
In practice: A plant uses an MBBR stage for biological treatment.
Mbps — Megabits per second
Municipal broadband & communications · Unit or symbol · Municipal broadband — A data-transfer rate measured in millions of bits each second.
In practice: A broadband plan lists a download rate in Mbps.
Megabits are not megabytes; advertised and actual rates can differ.
MBR — Membrane bioreactor
Wastewater treatment & resource recovery · Technical term · Wastewater — A biological treatment system using membranes for solids separation.
In practice: An MBR retains biomass using membrane filtration.
MCA — Moderate consequence area
Natural gas & pipeline systems · Technical term · Natural gas — A gas-transmission regulatory area category based on specified population, building, and roadway conditions.
In practice: An operator evaluates whether a transmission segment lies in an MCA.
Mcf — Thousand cubic feet
Units, quantities & symbols · Unit or symbol · Cross-utility — A gas-volume unit equal to one thousand cubic feet under the stated reference conditions.
In practice: A production table reports volume in Mcf.
Volume-to-energy conversion requires the actual heating value and reference conditions.
MCL — Maximum contaminant level
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — An enforceable contaminant limit for drinking water under the applicable regulation.
In practice: A report compares a regulated result with its MCL.
MCLG — Maximum contaminant level goal
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A non-enforceable health-based goal for a drinking-water contaminant.
In practice: A CCR can list both the MCL and MCLG.
MCRT — Mean cell residence time
Wastewater treatment & resource recovery · Technical term · Wastewater — A solids-age measure used in biological wastewater process control.
In practice: A plant's process sheet calculates MCRT from its defined solids inventory and losses.
Often used similarly to SRT, but verify the plant's calculation convention.
MDMS — Meter data management system
Metering, billing & customer service · Technical term · Cross-utility — Software that stores, validates, and prepares meter data for billing and other uses.
In practice: The MDMS checks interval data before billing calculations.
MDM
MDPE — Medium-density polyethylene
Natural gas & pipeline systems · Technical term · Natural gas — A polyethylene material class used in applications including gas distribution pipe.
In practice: A gas material inventory distinguishes MDPE from other pipe materials.
MED — Major event day
Grid operations & reliability · Technical term · Electric power — A day classified as a major reliability event using the reporting methodology's criteria.
In practice: A report lists reliability values both with and without MEDs.
Not every storm day is automatically a MED.
MF — Microfiltration
Drinking water & distribution · Technical term · Drinking water — A membrane process that removes suspended particles and selected microorganisms within its rated performance.
In practice: A pilot tests MF on the utility's source water.
MFA — Multi-factor authentication
Controls, communications & cybersecurity · Technical term · Cross-utility — Authentication requiring factors from more than one category.
In practice: A remote-access policy requires MFA for eligible accounts.
MFL — Magnetic flux leakage
Natural gas & pipeline systems · Technical term · Natural gas — An inspection method using changes in magnetic flux to identify certain metal-loss or other features.
In practice: An ILI report includes indications from an MFL tool.
mg/L — Milligrams per liter
Units, quantities & symbols · Unit or symbol · Cross-utility — A mass concentration unit often used for constituents in water.
In practice: A laboratory reports suspended solids in mg/L.
mg/L and ppm are approximately numerically equal in dilute water near a density of 1 kg/L, not universally interchangeable.
MGD — Million gallons per day
Units, quantities & symbols · Unit or symbol · Cross-utility — A flow rate expressed here in millions of U.S. liquid gallons per day.
In practice: A treatment plant reports average influent flow in MGD.
MISO — Midcontinent Independent System Operator
U.S. agencies & organizations · Organization · U.S. specific — The regional organization operating transmission and markets across its multistate footprint.
In practice: A generator participates in the MISO market.
MLSS — Mixed liquor suspended solids
Wastewater treatment & resource recovery · Technical term · Wastewater — The suspended solids concentration in mixed liquor within an activated-sludge process.
In practice: An operator trends MLSS in the aeration basin.
MLVSS — Mixed liquor volatile suspended solids
Wastewater treatment & resource recovery · Technical term · Wastewater — The volatile portion of mixed liquor suspended solids under the test method.
In practice: A process calculation uses MLVSS as an approximate biological-solids indicator.
MMBtu — Million British thermal units
Units, quantities & symbols · Unit or symbol · Cross-utility — An energy quantity equal to one million Btu.
In practice: A wholesale gas contract quotes a price per MMBtu.
MM conventionally denotes million here; MBtu can be ambiguous.
MMcf — Million cubic feet
Units, quantities & symbols · Unit or symbol · Cross-utility — A gas-volume unit equal to one million cubic feet under the stated reference conditions.
In practice: A storage report lists gas volume in MMcf.
MMCF
MOP — Maximum operating pressure
Natural gas & pipeline systems · Technical term · Natural gas — An operating-pressure term whose formal meaning depends on the pipeline service and governing rule.
In practice: An engineer checks the governing definition before comparing MOP and MAOP.
Do not substitute MOP for the regulated gas-pipeline term MAOP without checking context.
MRDL — Maximum residual disinfectant level
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The enforceable maximum for a disinfectant residual under the applicable drinking-water regulation.
In practice: A utility monitors disinfectant residuals against applicable MRDL requirements.
MRDLG — Maximum residual disinfectant level goal
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A non-enforceable health-based goal for a drinking-water disinfectant residual.
In practice: A drinking-water report distinguishes the MRDLG from the enforceable limit.
MS4 — Municipal separate storm sewer system
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A qualifying publicly owned stormwater conveyance system distinct from a combined or sanitary sewer.
In practice: A municipality administers its MS4 stormwater program.
MTBF — Mean time between failures
Asset management & field projects · Performance metric · Cross-utility — An average operating-time measure between failures for repairable items under a stated dataset and definition.
In practice: A maintenance report defines which failures enter its MTBF calculation.
MTBF is not a guarantee of an individual asset's remaining life.
MTTR — Mean time to repair
Asset management & field projects · Performance metric · Cross-utility — Average repair time under the stated start, stop, and event-counting conventions.
In practice: A utility separates repair time from travel and waiting when reporting MTTR.
Some organizations use restore or recovery in this abbreviation; confirm the metric definition.
MVA — Megavolt-ampere
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of apparent electrical power equal to one million volt-amperes.
In practice: A substation transformer has a rating expressed in MVA.
MW — Megawatt
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of power equal to one thousand kilowatts.
In practice: A generator has a stated net capacity of 50 MW.
MWh — Megawatt-hour
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit of energy equal to one thousand kilowatt-hours.
In practice: A battery dispatch delivers 20 MWh over a stated period.
NAN — Neighborhood area network
Metering, billing & customer service · Technical term · Cross-utility — A communications network linking devices within a neighborhood-scale service area.
In practice: A metering architecture uses a NAN between meters and collection points.
NARUC — National Association of Regulatory Utility Commissioners
U.S. agencies & organizations · Organization · U.S. specific — An association of utility regulators in the United States.
In practice: A policy team reviews a NARUC educational resource.
NDT — Nondestructive testing
Asset management & field projects · Technical term · Cross-utility — Examination methods that assess materials or components without intentionally destroying them.
In practice: A weld-quality plan specifies qualified NDT methods.
NEM — Net energy metering
Markets, rates & planning · Market or planning term · U.S. utility markets — A billing arrangement that accounts for eligible customer generation and electricity consumption under specified rules.
In practice: A customer's PV bill reflects the applicable NEM tariff.
Export credits, eligibility, and successor tariffs vary by utility and jurisdiction.
NERC — North American Electric Reliability Corporation
U.S. agencies & organizations · Organization · U.S. specific — The organization serving as the electric reliability organization for the North American bulk power system under applicable oversight.
In practice: A compliance team consults NERC reliability standards.
NERC's geographic scope extends beyond the United States.
NF — Nanofiltration
Drinking water & distribution · Technical term · Drinking water — A membrane separation process generally operating between ultrafiltration and reverse osmosis in separation characteristics.
In practice: A utility evaluates NF for hardness and organic-matter reduction.
NGA — Natural Gas Act
Markets, rates & planning · Market or planning term · U.S. utility markets — A federal statute addressing interstate natural gas transportation and certain sales and facilities.
In practice: A pipeline application cites the NGA.
NGV — Natural gas vehicle
Natural gas & pipeline systems · Technical term · Natural gas — A vehicle fueled by natural gas, commonly as CNG or LNG.
In practice: A municipal fleet compares NGV and battery-electric options.
NIMS — National Incident Management System
Safety & emergency management · Safety term · Cross-utility — The U.S. framework for coordinating incident management across organizations and jurisdictions.
In practice: A utility aligns response coordination with NIMS concepts.
NOM — Natural organic matter
Drinking water & distribution · Technical term · Drinking water — Naturally occurring organic material in source water that can influence treatment and byproduct formation.
In practice: A utility tracks NOM changes after a runoff event.
NOx — Nitrogen oxides
Environmental management & emissions · Chemical symbol · Cross-utility — A collective label for specified nitrogen-oxide compounds associated with combustion and air-quality impacts.
In practice: A unit's emissions report includes NOx results.
NPDES — National Pollutant Discharge Elimination System
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — The permitting program for regulated point-source discharges to waters within its scope.
In practice: A wastewater facility reviews its NPDES permit conditions.
NPDWR — National Primary Drinking Water Regulation
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A federal drinking-water regulation addressing contaminants or treatment requirements for public water systems.
In practice: A compliance plan identifies the applicable NPDWR requirements.
NPMS — National Pipeline Mapping System
Natural gas & pipeline systems · Technical term · Natural gas — PHMSA's mapping system for designated pipeline infrastructure information.
In practice: A planner uses the public NPMS viewer for general awareness.
Public maps are not precise excavation-location tools and do not replace a locate request.
NPV — Net present value
Asset management & field projects · Technical term · Cross-utility — The value of future cash flows discounted to a common date, net of relevant costs.
In practice: An asset-renewal analysis compares NPV under stated assumptions.
NRC — Nuclear Regulatory Commission
U.S. agencies & organizations · Organization · U.S. specific — The U.S. regulator for civilian use of nuclear materials and facilities within its authority.
In practice: A utility follows NRC licensing requirements for a reactor.
NRECA — National Rural Electric Cooperative Association
U.S. agencies & organizations · Organization · U.S. specific — The national organization representing electric cooperatives in the United States.
In practice: A cooperative reviews NRECA industry information.
NRW — Non-revenue water
Drinking water & distribution · Technical term · Drinking water — Water entering a distribution system that does not generate billed revenue, including defined loss and authorized-use components.
In practice: A water audit separates NRW into its underlying components.
NRW includes more than physical leakage.
NTNCWS — Non-transient non-community water system
Drinking water & distribution · Technical term · Drinking water — A public system regularly serving a substantially consistent group of people without being a community water system.
In practice: A qualifying school or factory supply may be an NTNCWS.
Formal population and duration criteria apply.
NTU — Nephelometric turbidity unit
Units, quantities & symbols · Unit or symbol · Cross-utility — A unit for turbidity measured by a specified nephelometric method.
In practice: A plant trends filtered-water turbidity in NTU.
Measurement method and reporting requirements matter.
NYISO — New York Independent System Operator
U.S. agencies & organizations · Organization · U.S. specific — The organization operating New York's bulk electricity system and wholesale markets.
In practice: A New York generator receives a NYISO market settlement.
O&M — Operations and maintenance
Asset management & field projects · Technical term · Cross-utility — The activities and costs required to operate and maintain utility facilities and services.
In practice: A budget separates recurring O&M from capital projects.
O and M;OM
OASIS — Open Access Same-Time Information System
Markets, rates & planning · Market or planning term · U.S. utility markets — An electronic system for transmission-service information and reservation processes.
In practice: A customer checks posted transmission availability through OASIS.
OATT — Open Access Transmission Tariff
Markets, rates & planning · Market or planning term · U.S. utility markets — The tariff describing terms and conditions for nondiscriminatory transmission service.
In practice: A transmission customer checks the OATT for service options.
OMS — Outage management system
Electric equipment & distribution · Technical term · Electric power — Software that tracks outages, affected customers, restoration work, and associated network information.
In practice: Customer calls and meter events help the OMS estimate an outage location.
OPEX — Operating expenditure
Asset management & field projects · Technical term · Cross-utility — Spending associated with ongoing operations under the applicable accounting policy.
In practice: A budget includes OPEX for routine services and supplies.
OPR — Owner's project requirements
Asset management & field projects · Technical term · Cross-utility — The owner's documented needs, performance objectives, and expectations for a project.
In practice: The design review checks the proposal against the OPR.
OPS — Office of Pipeline Safety
U.S. agencies & organizations · Organization · U.S. specific — PHMSA's office responsible for pipeline safety programs.
In practice: An operator consults OPS guidance on pipeline reporting.
OQ — Operator qualification
Natural gas & pipeline systems · Technical term · Natural gas — The qualification framework for personnel performing covered pipeline tasks.
In practice: A supervisor checks OQ records before assigning a covered task.
ORP — Oxidation-reduction potential
Wastewater treatment & resource recovery · Technical term · Wastewater — An electrical potential indicating the tendency of a solution to accept or donate electrons under measurement conditions.
In practice: A process operator reviews ORP trends alongside other measurements.
OSHA — Occupational Safety and Health Administration
Safety & emergency management · Safety term · Cross-utility — The U.S. agency responsible for federal occupational safety and health standards and enforcement within its authority.
In practice: A safety team reviews OSHA electric-power resources.
OT — Operational technology
Controls, communications & cybersecurity · Technical term · Cross-utility — Hardware and software that monitor or control physical devices and processes.
In practice: The utility separates OT needs from office-computing requirements.
In payroll, OT instead means overtime.
OT — Overtime
Workforce, time & administration · Workforce term · Cross-utility — Working time or compensation treated as overtime under the applicable law, agreement, or policy.
In practice: A payroll reviewer checks how OT applies to approved hours.
Do not assume all long shifts trigger the same overtime rule; OT also means operational technology.
PAC — Powdered activated carbon
Drinking water & distribution · Technical term · Drinking water — Finely divided activated carbon added to water to adsorb selected compounds.
In practice: A plant evaluates PAC for a seasonal taste-and-odor issue.
PAC can also refer to polyaluminum chloride; confirm the chemical and product name.
PAC — Polyaluminum chloride
Drinking water & distribution · Technical term · Drinking water — An aluminum-based coagulant used in some water-treatment processes.
In practice: A treatment trial compares PAC with another coagulant.
Spell out the chemical: powdered activated carbon uses the same abbreviation.
PACS — Physical Access Control Systems
Controls, communications & cybersecurity · Technical term · Cross-utility — Systems controlling or recording physical access under the applicable NERC definition.
In practice: A compliance team classifies a relevant access-control system as PACS.
PCS — Power conversion system
Generation, storage & electrification · Technical term · Electric power — Equipment that converts electrical power between forms needed by a storage system and the network.
In practice: The PCS converts battery DC to grid-compatible AC.
PDC — Phasor data concentrator
Grid operations & reliability · Technical term · Electric power — A system that aligns and combines time-stamped phasor measurements from multiple sources.
In practice: A PDC gathers measurements before sending them to a monitoring application.
PdM — Predictive maintenance
Asset management & field projects · Technical term · Cross-utility — Maintenance planning informed by condition data and predictions of degradation or failure.
In practice: Vibration trends support a PdM decision for a motor.
PE — Polyethylene
Natural gas & pipeline systems · Technical term · Natural gas — A thermoplastic widely used in natural gas and water distribution pipe.
In practice: A replacement project specifies PE gas pipe under the applicable standard.
PE can also mean professional engineer in staffing and design documents.
PE — Professional engineer
Asset management & field projects · Credential · Cross-utility — An engineer licensed under the applicable jurisdiction's requirements.
In practice: A project confirms the PE licensing requirements for design approval.
This is a credential, while PE on a pipe schedule may mean polyethylene.
PF — Power factor
Units, quantities & symbols · Unit or symbol · Cross-utility — The ratio of real power to apparent power for the stated electrical conditions.
In practice: A facility reviews PF when assessing motor loads and utility charges.
Use true power factor or displacement power factor as appropriate to the measurement.
PFAS — Per- and polyfluoroalkyl substances
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A large family of manufactured fluorinated substances with varied properties and uses.
In practice: A water utility evaluates PFAS monitoring and treatment options.
Specific substances, limits, and implementation dates must be checked against current requirements.
PFOA — Perfluorooctanoic acid
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A specific substance within the PFAS family.
In practice: A laboratory reports PFOA separately from other PFAS.
PFOS — Perfluorooctanesulfonic acid
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A specific substance within the PFAS family.
In practice: A water-quality dataset contains an individual PFOS result.
PHEV — Plug-in hybrid electric vehicle
Generation, storage & electrification · Technical term · Electric power — A vehicle combining an externally rechargeable battery with another propulsion energy source.
In practice: A fleet model separates BEV and PHEV charging needs.
PHMSA — Pipeline and Hazardous Materials Safety Administration
U.S. agencies & organizations · Organization · U.S. specific — The U.S. transportation agency responsible for pipeline and hazardous-materials safety oversight.
In practice: A gas utility reviews PHMSA pipeline safety guidance.
PIC — Potential impact circle
Natural gas & pipeline systems · Technical term · Natural gas — The geographic circle defined using the potential impact radius at a pipeline location.
In practice: The mapping team checks structures within a PIC.
PIPP — Percentage of income payment plan
Metering, billing & customer service · Technical term · Cross-utility — A jurisdiction- or utility-specific bill-payment arrangement based on an eligible household's income.
In practice: A customer asks whether a local PIPP is available.
PIPP is not a single nationwide utility benefit; availability and terms differ.
PIR — Potential impact radius
Natural gas & pipeline systems · Technical term · Natural gas — A calculated radius used to assess the potential impact area of a gas pipeline failure under specified assumptions.
In practice: A transmission assessment uses PIR when evaluating consequence-area criteria.
PJM — PJM Interconnection
U.S. agencies & organizations · Organization · U.S. specific — The regional transmission organization serving its Mid-Atlantic and adjacent-state footprint.
In practice: A generator submits market offers to PJM.
PJM historically derives from Pennsylvania–New Jersey–Maryland; its present footprint is broader.
PLC — Programmable logic controller
Controls, communications & cybersecurity · Technical term · Cross-utility — An industrial controller that executes programmed logic to control equipment or processes.
In practice: A PLC controls a pump sequence according to the approved design.
PLC — Power line communication
Controls, communications & cybersecurity · Technical term · Cross-utility — Communication technology that carries data signals over electrical power conductors.
In practice: A meter communications design evaluates PLC coverage.
Spell out PLC when control engineers and metering teams work together.
PM — Preventive maintenance
Asset management & field projects · Technical term · Cross-utility — Maintenance performed at planned intervals or usage thresholds to reduce failure risk.
In practice: A pump has a scheduled PM inspection.
PMA — Power marketing administration
U.S. agencies & organizations · Organization · U.S. specific — A federal organization marketing power from designated federal generation projects.
In practice: A municipal utility evaluates an allocation from a PMA.
PMU — Phasor measurement unit
Grid operations & reliability · Technical term · Electric power — A device that measures synchronized voltage or current phasors using a common time reference.
In practice: PMU data helps engineers compare conditions at distant substations.
POTW — Publicly owned treatment works
Wastewater treatment & resource recovery · Technical term · Wastewater — A publicly owned wastewater treatment system within the applicable Clean Water Act definition.
In practice: An industrial user discharges to a POTW under its control program.
PPA — Power purchase agreement
Markets, rates & planning · Market or planning term · U.S. utility markets — A contract governing electricity purchases, with commercial terms such as price, quantity, and delivery.
In practice: A solar developer signs a PPA with an electricity buyer.
ppb — Parts per billion
Units, quantities & symbols · Unit or symbol · Cross-utility — A ratio expressing one part per billion parts of a specified mixture.
In practice: A laboratory or instrument specifies the basis of a ppb result.
PPE — Personal protective equipment
Safety & emergency management · Safety term · Cross-utility — Equipment worn to reduce exposure to identified workplace hazards.
In practice: A job assessment identifies the required PPE.
Selection depends on the hazard assessment, equipment specifications, and applicable procedures.
ppm — Parts per million
Units, quantities & symbols · Unit or symbol · Cross-utility — A ratio expressing one part of a substance per million parts of the specified mixture.
In practice: A gas reading states whether its ppm basis is by volume.
The basis must be stated; ppm is not inherently a mass-per-volume unit.
PRCS — Permit-required confined space
Safety & emergency management · Safety term · Cross-utility — A confined space meeting the applicable criteria for a permit-required space.
In practice: A utility evaluates a vault under its confined-space program.
Entry decisions require the actual assessment, training, and procedures.
PRM — Planning reserve margin
Markets, rates & planning · Performance metric · U.S. utility markets — Planned available capacity above forecast peak demand, expressed relative to that demand.
In practice: A resource plan states its PRM assumptions.
PRV — Pressure reducing valve
Drinking water & distribution · Technical term · Drinking water — A valve that reduces downstream pressure to a controlled level.
In practice: A water distribution zone uses a PRV to manage service pressure.
PRV can mean pressure relief valve in equipment documents.
PSC — Public service commission
U.S. agencies & organizations · Organization · U.S. specific — A name used by some jurisdictions for a utility or public-service regulator.
In practice: A state PSC reviews an eligible utility rate case.
PSH — Pumped storage hydropower
Generation, storage & electrification · Technical term · Electric power — Energy storage that pumps water to a higher reservoir and later generates electricity as it flows down.
In practice: PSH stores energy during pumping and returns some during generation.
psi — Pounds per square inch
Units, quantities & symbols · Unit or symbol · Cross-utility — A customary pressure unit.
In practice: A gauge specification states its pressure range in psi.
psia — Pounds per square inch absolute
Units, quantities & symbols · Unit or symbol · Cross-utility — Pressure measured relative to a perfect vacuum.
In practice: A gas calculation requires absolute pressure in psia.
Convert using the applicable atmospheric pressure, not an unexplained fixed offset.
psig — Pounds per square inch gauge
Units, quantities & symbols · Unit or symbol · Cross-utility — Pressure measured relative to local atmospheric pressure.
In practice: A pipeline instrument displays gauge pressure in psig.
PSP — Physical Security Perimeter
Controls, communications & cybersecurity · Technical term · Cross-utility — The physical boundary protecting specified assets under the applicable NERC framework.
In practice: A site review checks the documented PSP boundary.
PT — Potential transformer
Electric equipment & distribution · Technical term · Electric power — An instrument transformer that provides a scaled voltage for measurement or protection.
In practice: The relay drawing shows the PT secondary connections.
Voltage transformer is another common name in this context.
PTO — Paid time off
Workforce, time & administration · Workforce term · Cross-utility — Paid leave offered or administered under applicable employer policy and legal requirements.
In practice: A scheduler accounts for approved PTO when planning coverage.
PUC — Public utility commission
U.S. agencies & organizations · Organization · U.S. specific — A state or other jurisdictional body regulating specified utility services.
In practice: A utility files a rate application with its PUC.
Names, responsibilities, and jurisdiction vary; not every utility is regulated identically.
PURPA — Public Utility Regulatory Policies Act
Markets, rates & planning · Market or planning term · U.S. utility markets — A U.S. law with provisions affecting qualifying facilities and utility regulatory policies.
In practice: A renewable project reviews the PURPA framework for its sale arrangement.
PV — Photovoltaic
Generation, storage & electrification · Technical term · Electric power — Conversion of light into electricity using semiconductor devices.
In practice: A rooftop PV array feeds an inverter.
PWR — Pressurized water reactor
Generation, storage & electrification · Technical term · Electric power — A nuclear reactor design that keeps the primary coolant under pressure and transfers heat to a separate steam system.
In practice: A training document distinguishes a PWR from a BWR.
PWS — Public water system
Drinking water & distribution · Technical term · Drinking water — A system supplying water for human consumption that meets the applicable public-system criteria.
In practice: A utility record identifies its PWS classification.
Federal criteria include service-connection or population-and-duration tests; private wells are not automatically PWSs.
QA — Quality assurance
Asset management & field projects · Technical term · Cross-utility — Planned activities that provide confidence that processes will meet requirements.
In practice: A project QA plan defines reviews and responsibilities.
QC — Quality control
Asset management & field projects · Technical term · Cross-utility — Checks and activities used to verify that work or output meets requirements.
In practice: A QC inspection documents whether installed equipment meets the specification.
QF — Qualifying facility
Markets, rates & planning · Market or planning term · U.S. utility markets — A cogeneration or small-power-production facility meeting the applicable PURPA criteria.
In practice: A project evaluates QF status and certification requirements.
Size, fuel, ownership, and other requirements depend on the facility category and applicable rules.
QL — Quality level
Asset management & field projects · Technical term · Cross-utility — A classification describing the basis and reliability of subsurface utility information.
In practice: A drawing identifies the QL of mapped utility information.
Use the governing standard's definitions; a map is not a substitute for a required locate process.
RA — Resource adequacy
Markets, rates & planning · Market or planning term · U.S. utility markets — The ability of available resources to meet demand with the required reliability under the relevant planning framework.
In practice: A utility demonstrates its RA position for a future season.
RAS — Remedial Action Scheme
Grid operations & reliability · Technical term · Electric power — A scheme that detects specified system conditions and takes planned corrective actions beyond conventional fault clearing.
In practice: A transmission study models a RAS that changes generation after a contingency.
RAS — Return activated sludge
Wastewater treatment & resource recovery · Technical term · Wastewater — Settled activated sludge returned to a biological treatment process.
In practice: The RAS flow returns solids from the clarifier to the aeration basin.
Electric-grid documents use RAS for remedial action scheme.
RBAC — Role-based access control
Controls, communications & cybersecurity · Technical term · Cross-utility — Authorization that assigns permissions according to defined roles.
In practice: An operator role receives only the access needed for its duties.
RC — Reliability Coordinator
Grid operations & reliability · Technical term · Electric power — The entity with wide-area visibility and authority for reliable operation across its reliability coordination area.
In practice: An RC coordinates responses to a developing regional transmission constraint.
RCA — Root cause analysis
Asset management & field projects · Technical term · Cross-utility — A structured investigation of underlying causes contributing to an event or problem.
In practice: A repeated equipment trip triggers an RCA.
RCM — Reliability-centered maintenance
Asset management & field projects · Technical term · Cross-utility — A structured approach selecting maintenance tasks based on functions, failure modes, and consequences.
In practice: A utility performs an RCM review on a critical pump station.
RCV — Remote-control valve
Natural gas & pipeline systems · Technical term · Natural gas — A valve that can be operated from a remote location.
In practice: SCADA displays the status of an RCV.
REC — Renewable energy certificate
Markets, rates & planning · Market or planning term · U.S. utility markets — A certificate representing the renewable attributes of one megawatt-hour of qualifying electricity generation.
In practice: An organization retires RECs to support a renewable-electricity claim.
A REC tracks attributes; it is not a physical delivery of electrons.
RMV — Rupture-mitigation valve
Natural gas & pipeline systems · Technical term · Natural gas — A valve meeting the applicable pipeline-rule criteria for reducing consequences of a rupture.
In practice: An operator evaluates the RMV requirements for a covered project.
RNG — Renewable natural gas
Natural gas & pipeline systems · Technical term · Natural gas — Biogas upgraded to a quality suitable for specified natural-gas uses.
In practice: A wastewater facility considers upgrading digester gas to RNG.
Pipeline injection requires meeting the receiving system's gas-quality requirements.
RO — Reverse osmosis
Drinking water & distribution · Technical term · Drinking water — A pressure-driven membrane process that separates water from many dissolved constituents.
In practice: A desalination system uses RO membranes.
ROE — Return on equity
Markets, rates & planning · Market or planning term · U.S. utility markets — A measure of earnings relative to equity; in regulation, an allowed equity return may form part of the revenue requirement.
In practice: A rate case examines the proposed allowed ROE.
ROW — Right-of-way
Asset management & field projects · Technical term · Cross-utility — Land rights or a defined corridor used for utility facilities and access.
In practice: A line project checks ROW rights and restrictions.
The extent of rights depends on the governing documents and law.
RPS — Renewable portfolio standard
Markets, rates & planning · Market or planning term · U.S. utility markets — A jurisdiction's requirement for a specified share or quantity of eligible renewable electricity.
In practice: A utility tracks eligible resources for its RPS obligation.
RPZ — Reduced pressure zone
Drinking water & distribution · Technical term · Drinking water — A common label for the reduced-pressure principle used in certain backflow-prevention assemblies.
In practice: A service record identifies the specified RPZ assembly and testing status.
Use the assembly's approved designation and applicable plumbing or water-system rules.
RTCR — Revised Total Coliform Rule
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The federal drinking-water rule addressing total-coliform monitoring and related assessments and corrective actions.
In practice: A system follows its approved RTCR monitoring plan.
RTE — Round-trip efficiency
Generation, storage & electrification · Technical term · Electric power — Energy delivered from storage divided by energy charged into it over a defined cycle and measurement boundary.
In practice: An RTE comparison states whether auxiliary loads are included.
RTM — Real-time market
Markets, rates & planning · Market or planning term · U.S. utility markets — A market that balances and prices electricity close to actual delivery.
In practice: A generator's deviations are settled under RTM rules.
RTO — Regional transmission organization
Markets, rates & planning · Market or planning term · U.S. utility markets — An independent organization that operates a regional transmission system and administers electricity markets under its arrangements.
In practice: A generator follows its RTO's scheduling and settlement rules.
RTP — Real-time pricing
Markets, rates & planning · Market or planning term · U.S. utility markets — Pricing that changes with short-interval market or system conditions according to the tariff.
In practice: A facility adjusts its operations in response to RTP signals.
RTU — Remote terminal unit
Controls, communications & cybersecurity · Technical term · Cross-utility — A field device that gathers signals and exchanges monitoring or control information with a supervisory system.
In practice: An RTU reports a remote pumping station's status.
RUS — Rural Utilities Service
U.S. agencies & organizations · Organization · U.S. specific — A USDA agency supporting rural infrastructure through utility programs and financing.
In practice: A rural system evaluates RUS funding options.
SAIDI — System Average Interruption Duration Index
Grid operations & reliability · Performance metric · Electric power — Total customer interruption minutes divided by customers served, expressing average outage duration per customer.
In practice: A reliability report presents SAIDI in minutes per customer for the reporting year.
Check whether major event days and other exclusions are included before comparing reports.
SAIFI — System Average Interruption Frequency Index
Grid operations & reliability · Performance metric · Electric power — Total sustained customer interruptions divided by customers served, expressing average interruption frequency.
In practice: A SAIFI of 1.2 represents 1.2 sustained interruptions per customer on average.
Use consistent reporting periods, customer counts, and event exclusions.
SBR — Sequencing batch reactor
Wastewater treatment & resource recovery · Technical term · Wastewater — A biological treatment process using timed treatment phases in a batch-oriented reactor.
In practice: An SBR cycle includes reaction and settling phases.
SCADA — Supervisory control and data acquisition
Controls, communications & cybersecurity · Technical term · Cross-utility — A system for observing remote equipment and issuing supervisory commands through communications links.
In practice: SCADA brings pump status and substation measurements into a control room.
SCBA — Self-contained breathing apparatus
Safety & emergency management · Safety term · Cross-utility — Respiratory equipment that supplies breathing air from a source carried by the user.
In practice: A trained response team uses specified SCBA equipment under its program.
SCC — Stress corrosion cracking
Natural gas & pipeline systems · Technical term · Natural gas — Cracking caused by the interaction of tensile stress, susceptible material, and an appropriate environment.
In practice: An integrity investigation evaluates possible SCC.
SCCDA — Stress corrosion cracking direct assessment
Natural gas & pipeline systems · Technical term · Natural gas — A structured assessment approach addressing susceptibility to stress corrosion cracking.
In practice: A pipeline integrity review considers SCCDA under the applicable criteria.
SCR — Selective catalytic reduction
Environmental management & emissions · Technical term · Cross-utility — A catalytic process used to reduce nitrogen oxides in exhaust streams.
In practice: A generating unit uses SCR as part of its emissions-control system.
SDR — Standard dimension ratio
Natural gas & pipeline systems · Technical term · Natural gas — A standardized series of dimension ratios used to classify thermoplastic pipe geometry.
In practice: A specification calls for a particular SDR pipe.
Pressure capability also depends on material, temperature, standards, and service.
SDS — Safety data sheet
Safety & emergency management · Safety term · Cross-utility — A structured document describing a chemical product's hazards and handling information.
In practice: A crew checks the product's current SDS.
SDWA — Safe Drinking Water Act
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The federal law providing the framework for U.S. public drinking-water protection.
In practice: A utility reviews rules established under the SDWA.
SDWIS — Safe Drinking Water Information System
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — EPA's system for public-water-system inventory and compliance information.
In practice: An analyst reviews SDWIS records for a public system.
SF6 — Sulfur hexafluoride
Environmental management & emissions · Chemical symbol · Cross-utility — An insulating gas historically used in certain electrical equipment and a potent greenhouse gas.
In practice: An equipment inventory records SF6-containing switchgear.
SIEM — Security information and event management
Controls, communications & cybersecurity · Technical term · Cross-utility — A platform that collects and correlates security-related events and logs.
In practice: Analysts use a SIEM to investigate related alerts.
SIF — Safety instrumented function
Controls, communications & cybersecurity · Technical term · Cross-utility — A defined safety function performed by a safety instrumented system.
In practice: A hazard study identifies the need for a specific SIF.
SIL — Safety integrity level
Controls, communications & cybersecurity · Technical term · Cross-utility — A discrete target or capability level used for a safety function under the applicable functional-safety standard.
In practice: The project documents the required SIL for a defined function.
SIL applies to specified functions and assumptions, not a blanket promise that a whole facility is safe.
SIS — Safety instrumented system
Controls, communications & cybersecurity · Technical term · Cross-utility — An instrumented system implementing specified safety functions under its lifecycle requirements.
In practice: A facility documents the boundary between the SIS and routine process control.
SIU — Significant industrial user
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — An industrial discharger meeting the applicable pretreatment-program criteria for significance.
In practice: A POTW identifies SIUs within its service area.
SMR — Small modular reactor
Generation, storage & electrification · Technical term · Electric power — A reactor design characterized by smaller unit scale and modular fabrication or deployment approaches.
In practice: A utility evaluates an SMR proposal as part of long-term resource planning.
Licensing status and commercial readiness are project-specific.
SMYS — Specified minimum yield strength
Natural gas & pipeline systems · Technical term · Natural gas — The minimum yield strength specified for a pipe material under the applicable specification.
In practice: A pipeline design calculation identifies the pipe's SMYS.
SO2 — Sulfur dioxide
Environmental management & emissions · Chemical symbol · Cross-utility — A sulfur-oxide gas associated with combustion of sulfur-containing fuels and other processes.
In practice: FGD equipment reduces SO2 in flue gas.
SOC — State of charge
Generation, storage & electrification · Technical term · Electric power — The estimated stored charge of a battery relative to a defined full-charge reference.
In practice: A dispatch plan preserves a minimum SOC for backup service.
The estimate depends on the battery and its management system.
SOC — Security operations center
Controls, communications & cybersecurity · Technical term · Cross-utility — A team or function responsible for security monitoring, investigation, and response.
In practice: The SOC coordinates an investigation with the OT operations team.
Battery documents use SOC for state of charge.
SOH — State of health
Generation, storage & electrification · Technical term · Electric power — A measure of battery condition relative to a reference condition, often involving remaining capacity or resistance.
In practice: The maintenance team tracks SOH as the battery ages.
SOL — System Operating Limit
Grid operations & reliability · Technical term · Electric power — An operating boundary for a system configuration based on equipment, stability, or other reliability criteria.
In practice: An outage changes the applicable SOL for a transmission path.
SOP — Standard operating procedure
Asset management & field projects · Technical term · Cross-utility — An approved document describing how a routine activity is performed within an organization.
In practice: A crew follows the current SOP for its assigned task.
SPCC — Spill Prevention, Control, and Countermeasure
Environmental management & emissions · Technical term · Cross-utility — An EPA oil-spill prevention planning framework for facilities meeting the applicable criteria.
In practice: A facility determines whether an SPCC plan is required.
Applicability and plan requirements must be checked against the current oil-pollution prevention rules.
SPP — Southwest Power Pool
U.S. agencies & organizations · Organization · U.S. specific — The regional transmission organization administering grid and market services within its service arrangements.
In practice: A utility coordinates a transmission matter with SPP.
Membership and service footprints can change; consult SPP for current coverage.
SPS — Special Protection System
Grid operations & reliability · Legacy terminology · Electric power — An older term used for schemes now commonly described as remedial action schemes.
In practice: An older drawing labels a RAS as an SPS.
Legacy usage: consult the document's terminology and applicable standard.
SRT — Solids retention time
Wastewater treatment & resource recovery · Technical term · Wastewater — The average time solids remain in the biological treatment system under the stated calculation boundary.
In practice: An operator evaluates SRT while assessing process stability.
SSO — Sanitary sewer overflow
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — An overflow or release from a sanitary sewer system.
In practice: A utility investigates an SSO associated with a blockage.
STATCOM — Static synchronous compensator
Electric equipment & distribution · Technical term · Electric power — A power-electronic device that supplies or absorbs reactive power to support voltage.
In practice: A STATCOM provides dynamic voltage support near a weak grid connection.
SUE — Subsurface utility engineering
Asset management & field projects · Technical term · Cross-utility — Engineering processes used to manage risks associated with existing underground utilities.
In practice: A designer uses SUE information before finalizing an excavation plan.
SVC — Static VAR compensator
Electric equipment & distribution · Technical term · Electric power — A shunt-connected system that controls reactive power through switched or controlled components.
In practice: An SVC helps regulate voltage at a transmission substation.
SVI — Sludge volume index
Wastewater treatment & resource recovery · Technical term · Wastewater — A settling indicator relating settled sludge volume to mixed-liquor solids concentration.
In practice: A plant tracks SVI when investigating settling changes.
SWMP — Stormwater management program
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A program for managing stormwater obligations and practices under the applicable permit or local framework.
In practice: An MS4 documents required measures in its SWMP.
SWPPP — Stormwater pollution prevention plan
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A site-specific plan identifying potential stormwater pollution and control practices under the applicable permit.
In practice: A utility construction project maintains its required SWPPP.
SWTR — Surface Water Treatment Rule
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The drinking-water rule framework addressing treatment of surface water and specified influenced groundwater.
In practice: A utility checks the applicable SWTR treatment provisions.
T&A — Time and attendance
Workforce, time & administration · Workforce term · Cross-utility — The recording and management of employee working time, attendance, and related exceptions.
In practice: A utility reconciles T&A records with approved crew assignments.
T and A;TA
T&D — Transmission and distribution
Electric equipment & distribution · Technical term · Electric power — The networks that move electricity from bulk supply points to customers.
In practice: A utility separates T&D investment from generation spending.
Also used as an organizational or cost-reporting label.
TADS — Transmission Availability Data System
Grid operations & reliability · Technical term · Electric power — NERC's system for collecting transmission outage and availability information.
In practice: A transmission owner classifies an outage for TADS reporting.
TBEL — Technology-based effluent limit
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A discharge limit based on required treatment-technology performance rather than solely receiving-water conditions.
In practice: A permit writer evaluates the applicable TBEL.
TDS — Total dissolved solids
Drinking water & distribution · Technical term · Drinking water — The dissolved solids content determined using the applicable analytical method.
In practice: A desalination plant compares influent and product-water TDS.
TES — Thermal energy storage
Generation, storage & electrification · Technical term · Electric power — Storage of heat or cooling for use at a later time.
In practice: TES shifts a district cooling plant's electricity demand.
therm — Therm
Units, quantities & symbols · Unit or symbol · Cross-utility — A customary energy unit equal to 100,000 Btu.
In practice: A residential natural-gas bill reports consumption in therms.
TIMP — Transmission integrity management program
Natural gas & pipeline systems · Technical term · Natural gas — A commonly used label for a gas transmission pipeline integrity management program.
In practice: A transmission operator schedules assessments within its TIMP.
Program labels vary; the applicable regulations define the requirements.
TKN — Total Kjeldahl nitrogen
Wastewater treatment & resource recovery · Technical term · Wastewater — The nitrogen fraction comprising organic nitrogen and ammonia under the Kjeldahl method.
In practice: A nutrient assessment combines TKN with oxidized nitrogen measurements.
TMDL — Total maximum daily load
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A pollution-budget framework identifying allowable loading needed to meet water-quality standards.
In practice: A watershed plan addresses a nutrient TMDL.
TN — Total nitrogen
Wastewater treatment & resource recovery · Technical term · Wastewater — The total nitrogen content measured or calculated under the specified analytical approach.
In practice: An effluent report compares TN with the applicable permit condition.
TNCWS — Transient non-community water system
Drinking water & distribution · Technical term · Drinking water — A non-community public water system that does not regularly serve the same people under the non-transient criteria.
In practice: A qualifying roadside facility may operate a TNCWS.
TO — Transmission Owner
Grid operations & reliability · Technical term · Electric power — The entity that owns and maintains transmission facilities.
In practice: A TO supplies equipment ratings for a planning study.
TOC — Total organic carbon
Drinking water & distribution · Technical term · Drinking water — A measure of the carbon associated with organic material in a sample.
In practice: A plant uses TOC data to understand organic loading.
TOP — Transmission Operator
Grid operations & reliability · Technical term · Electric power — The entity responsible for operating its transmission system reliably.
In practice: The TOP reviews planned line outages before work starts.
TOU — Time-of-use
Markets, rates & planning · Market or planning term · U.S. utility markets — A rate structure with prices that vary by predefined time periods.
In practice: A customer shifts charging into a lower-priced TOU period.
TP — Total phosphorus
Wastewater treatment & resource recovery · Technical term · Wastewater — The phosphorus content determined after the specified preparation and analytical method.
In practice: A treatment study tracks TP removal.
TRM — Transmission Reliability Margin
Grid operations & reliability · Technical term · Electric power — Transfer capability reserved to address uncertainties affecting reliable transmission operation.
In practice: A methodology accounts for uncertainty through a TRM value.
TSP — Transmission Service Provider
Grid operations & reliability · Technical term · Electric power — The entity administering transmission services under the applicable tariff arrangements.
In practice: A customer submits a transmission service request to the TSP.
TSS — Total suspended solids
Wastewater treatment & resource recovery · Technical term · Wastewater — The suspended material retained and measured using the specified laboratory method.
In practice: An effluent report includes TSS in mg/L.
TT — Treatment technique
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — A required treatment method or process condition used in a drinking-water regulation.
In practice: A rule uses a TT requirement to address a specified risk.
TTC — Total Transfer Capability
Grid operations & reliability · Technical term · Electric power — The amount of electric power that can be transferred reliably under specified system conditions.
In practice: A study calculates TTC for a defined transmission interface.
TTHM — Total trihalomethanes
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — The regulated sum of specified trihalomethane disinfection byproducts.
In practice: A distribution sampling program reports TTHM concentrations.
TVA — Tennessee Valley Authority
U.S. agencies & organizations · Organization · U.S. specific — The federal corporation providing electricity and other regional services in its statutory service area.
In practice: A local power company purchases wholesale power from TVA.
UAFG — Unaccounted-for gas
Natural gas & pipeline systems · Technical term · Natural gas — The difference between gas inputs and accounted-for outputs after specified adjustments.
In practice: An LDC investigates measurement, timing, and leakage contributors to UAFG.
UAFG is not a direct measurement of methane leakage; accounting conventions matter.
UCMR — Unregulated Contaminant Monitoring Rule
Drinking-water rules & reporting · Program or regulatory term · U.S. specific — EPA's program requiring specified monitoring for selected contaminants lacking national primary regulations.
In practice: A covered water system collects samples under the applicable UCMR cycle.
UEL — Upper explosive limit
Safety & emergency management · Safety term · Cross-utility — The upper concentration boundary for flame propagation in air under specified test conditions.
In practice: A hazard reference lists a substance's UEL alongside its LEL.
UF — Ultrafiltration
Drinking water & distribution · Technical term · Drinking water — A membrane process used to remove particles and selected microorganisms according to membrane performance.
In practice: A treatment train uses UF ahead of another process.
UFLS — Underfrequency load shedding
Grid operations & reliability · Technical term · Electric power — Automatic load reduction triggered by low system frequency to support system stability.
In practice: A protection study documents UFLS stages.
A definition does not specify settings or authorize switching.
USDA — United States Department of Agriculture
U.S. agencies & organizations · Organization · U.S. specific — The federal department that includes rural-development and rural-utilities programs.
In practice: A rural water system consults USDA infrastructure resources.
UT — Ultrasonic testing
Natural gas & pipeline systems · Technical term · Natural gas — An examination method using ultrasonic waves to assess material or weld conditions.
In practice: A qualified inspector uses UT during a pipeline assessment.
UV — Ultraviolet
Drinking water & distribution · Technical term · Drinking water — Electromagnetic radiation used in water treatment for disinfection and certain photochemical processes.
In practice: A UV reactor provides a treatment barrier under validated conditions.
UV disinfection and UV-based advanced oxidation have different design objectives.
UVLS — Undervoltage load shedding
Grid operations & reliability · Technical term · Electric power — Automatic load reduction triggered by specified low-voltage conditions.
In practice: Engineers assess how a UVLS scheme supports voltage recovery.
V2B — Vehicle-to-building
Generation, storage & electrification · Technical term · Electric power — Bidirectional operation in which a vehicle supplies electricity to a building through compatible equipment.
In practice: A site studies V2B for backup power and demand management.
V2G — Vehicle-to-grid
Generation, storage & electrification · Technical term · Electric power — Bidirectional operation in which a vehicle can export electricity to the grid through compatible equipment and arrangements.
In practice: A pilot assesses V2G participation during peak demand.
VAR — Volt-ampere reactive
Units, quantities & symbols · Unit or symbol · Cross-utility — The unit used to express reactive power in an AC system.
In practice: A voltage-control study reports reactive requirements in VAR or its multiples.
Often written var in technical unit notation.
VEE — Validation, estimation, and editing
Metering, billing & customer service · Technical term · Cross-utility — Processes for checking meter data and addressing missing or suspect readings under approved rules.
In practice: The billing team reviews a VEE exception.
VLAN — Virtual local area network
Controls, communications & cybersecurity · Technical term · Cross-utility — A logical separation of devices into network segments within compatible switching infrastructure.
In practice: A site design assigns devices to VLANs as part of a wider segmentation approach.
A VLAN alone does not establish a complete security boundary.
VPN — Virtual private network
Controls, communications & cybersecurity · Technical term · Cross-utility — A logical private connection built over another network, commonly using encrypted tunnels.
In practice: A utility controls approved remote access through a VPN.
VPP — Virtual power plant
Generation, storage & electrification · Technical term · Electric power — A coordinated portfolio of distributed resources that provides aggregated grid or market services.
In practice: A VPP combines flexible loads and batteries across many sites.
VSS — Volatile suspended solids
Wastewater treatment & resource recovery · Technical term · Wastewater — The portion of suspended solids lost on ignition under the specified method.
In practice: A process review uses VSS to help characterize organic solids.
VT — Voltage transformer
Electric equipment & distribution · Technical term · Electric power — An instrument transformer that supplies a scaled representation of system voltage.
In practice: The metering diagram identifies the VT ratio.
VVO — Volt/VAR optimization
Electric equipment & distribution · Technical term · Electric power — Coordinated voltage and reactive-power control used to improve distribution performance.
In practice: VVO adjusts regulators and capacitor banks within approved limits.
WACC — Weighted average cost of capital
Markets, rates & planning · Market or planning term · U.S. utility markets — The combined cost of debt and equity weighted by the assumed capital structure.
In practice: A financing model uses WACC to evaluate a utility investment.
WAMS — Wide-area monitoring system
Grid operations & reliability · Technical term · Electric power — A system that combines geographically distributed measurements to reveal regional grid behavior.
In practice: WAMS displays help operators see oscillations across a region.
WAN — Wide area network
Metering, billing & customer service · Technical term · Cross-utility — A communications network connecting systems across larger geographic distances.
In practice: A utility WAN connects substations and control facilities.
WAS — Waste activated sludge
Wastewater treatment & resource recovery · Technical term · Wastewater — Activated sludge removed from the treatment process to control the solids inventory.
In practice: WAS is sent to the solids-handling process.
WET — Whole effluent toxicity
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — Testing or assessment of the combined toxic effect of an effluent sample using specified organisms and methods.
In practice: A permit requires WET testing at designated intervals.
WFM — Workforce management
Workforce, time & administration · Workforce term · Cross-utility — Coordinated scheduling, timekeeping, staffing, and related employee-administration processes.
In practice: A WFM system connects planned shifts with actual hours.
WH-347 — Payroll form WH-347
Workforce, time & administration · Workforce term · Cross-utility — A U.S. Department of Labor optional form for reporting payroll information on covered federal or federally assisted construction work.
In practice: A contractor uses WH-347 or an acceptable equivalent when applicable.
WIFIA — Water Infrastructure Finance and Innovation Act
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — The federal statute establishing a credit-assistance program for eligible water infrastructure.
In practice: A project team checks WIFIA eligibility and financing terms.
WO — Work order
Asset management & field projects · Technical term · Cross-utility — A record authorizing, describing, and tracking a defined job.
In practice: A WO links labor time, materials, and an asset identifier.
WQBEL — Water quality-based effluent limit
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — A discharge limit developed to protect applicable receiving-water quality standards.
In practice: A permit contains a WQBEL for a pollutant of concern.
WQS — Water quality standards
Wastewater permits & stormwater · Program or regulatory term · U.S. specific — The designated uses, criteria, and related provisions governing water quality under the applicable framework.
In practice: A permit review considers the receiving water's WQS.
WRRF — Water resource recovery facility
Wastewater treatment & resource recovery · Technical term · Wastewater — A wastewater facility described in terms of water, energy, and nutrient recovery as well as treatment.
In practice: A WRRF recovers biogas for useful energy.
WSP — Water safety plan
Drinking water & distribution · Technical term · Drinking water — A preventive risk-management plan addressing a drinking-water supply from source to consumer.
In practice: A utility maps hazards and control measures in its WSP.
Use the applicable local framework; this term does not establish a universal U.S. filing requirement.
WTP — Water treatment plant
Drinking water & distribution · Technical term · Drinking water — A facility that treats source water for its intended water-supply use.
In practice: A WTP operator reviews the day's process readings.
WWTP — Wastewater treatment plant
Wastewater treatment & resource recovery · Technical term · Wastewater — A facility that treats wastewater before discharge, reuse, or another authorized destination.
In practice: A WWTP tracks influent flow and effluent quality.
µg/L — Micrograms per liter
Units, quantities & symbols · Unit or symbol · Cross-utility — A mass concentration unit equal to one thousandth of a milligram per liter.
In practice: A drinking-water laboratory reports a trace constituent in µg/L.
THE CONNECTIONS MATTER
Similar letters. Different jobs.
Read reports and talk across disciplines with fewer misunderstandings. Explore ten distinctions that help prevent confusion.
kW vs. kWh
kW measures power: how fast energy is used or delivered. kWh measures energy over time. A steady 2 kW load running for 3 hours uses 6 kWh.
SAIDI vs. SAIFI vs. CAIDI
SAIDI measures interruption minutes per customer. SAIFI measures interruptions per customer. CAIDI measures duration per interruption. Match the reporting period and exclusions before comparing values.
CIP has three utility meanings
Grid security uses critical infrastructure protection. Asset planning uses capital improvement plan. Treatment facilities use clean-in-place. The department and document identify the intended meaning.
AMI vs. AMR
AMR automates collection of meter readings. AMI adds an infrastructure of communications and systems supporting defined two-way functions and interval data. Features depend on the actual installation.
MCL vs. MCLG vs. AL
An MCL is an enforceable contaminant limit. An MCLG is a non-enforceable health goal. An action level triggers specified responses under its rule. These terms describe different regulatory mechanisms.
BOD vs. COD
Biochemical oxygen demand uses a biological test; chemical oxygen demand uses chemical oxidation. They measure different fractions under different methods. BOD5 specifies a five-day test.
OT & ICS across departments
OT can mean operational technology or overtime. ICS can mean industrial control system or incident command system. Spell them out when operations, security, and workforce teams share a report.
CT: electricity or water?
Electrical metering uses a current transformer. Generation uses a combustion turbine. Water disinfection uses concentration multiplied by contact time. CT alone cannot identify the equipment or process.
Mcf vs. MMBtu vs. therm
Mcf measures gas volume. MMBtu and therm measure energy. One MMBtu equals ten therms. Converting gas volume to energy needs the actual heating value and reference conditions.
CSO vs. SSO vs. MS4
A CSO comes from a combined sewer. An SSO is an overflow from a sanitary sewer system. An MS4 is a separate municipal stormwater system. Different system types have different management requirements.
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Disclaimer: The TimeTrex USA Utilities Acronym Database is provided for general information and educational use only and does not constitute engineering, operational, regulatory, financial, or safety advice. Acronym meanings and search or decoding results may differ across electric, natural gas, water, and wastewater systems, utilities, and jurisdictions. TimeTrex does not guarantee the accuracy, completeness, or currency of the information. Definitions and examples do not authorize switching, establish treatment settings, confirm service availability, or determine rates or compliance. Verify terminology against current utility tariffs, permits, technical documents, and approved operating procedures, and consult qualified personnel before acting. References and external links do not imply endorsement.
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