Grid Glossary

TRENDING TERM

Critical Issue Fast Path (CIFP)

An accelerated stakeholder process used in PJM Interconnection to resolve urgent, contentious, and time-sensitive issues that cannot be resolved through the normal stakeholder process. The process involves several stages of discussion and proposal development, culminating in a submission to the Federal Energy Regulatory Commission (FERC) for approval. The CIFP process has been used in recent years to discuss large load additions (2025) and resource adequacy (2023).

TRENDING TERM

Effective Load Carrying Capability (ELCC)

Measurement used to calculate how much an energy resource–such as a wind farm or solar array–contributes to the overall reliability of the grid. It assesses the resource’s ability to meet electricity demand, particularly during peak usage periods, and is especially useful for variable renewable energy sources whose output depends on factors like weather conditions. 

TRENDING TERM

Disturbance

Refers to any unwanted or unplanned electrical event that interferes with the normal operation of the electrical grid. These can manifest in power outages, surges, and other events, and can originate from various sources within the electrical grid, such as loss of a large generating unit or another grid asset, such as a transmission line or transformer.

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Active power

Also known as real or true power, is the portion of electrical power that does useful work in a circuit, such as generating heat, light, or mechanical energy. (see related: reactive power)

Advance Notice of Proposed Rulemaking (ANOPR)

A preliminary document used by government agencies to solicit public feedback on potential new rules or reforms before they are officially proposed. It outlines initial ideas, asks specific questions, and serves as the first step in a larger regulatory process. The acronym is frequently used by the Federal Energy Regulatory Commission (FERC). It precedes a formal Notice of Proposed Rulemaking (NOPR) and allows agencies to gauge public opinion and gather information to develop a more informed proposal.

Ancillary services

(see also: Essential reliability services) – Supplementary services essential for maintaining the reliable operation and stability of the electrical grid beyond the basic generation and transmission of energy. They are “behind-the-scenes” services that include real-time balancing of electricity supply and demand, maintaining voltage levels, and providing the capability to restart the grid after a widespread outage (black start). 

Automatic Generation Control (AGC)

Is an automated system that continuously monitors the electrical network and adjusts the power output of multiple generators. Its primary functions are to maintain system frequency (60 Hz in United States), in response to changes in the power demand, or load.

Baseload

The minimum amount of electricity that a utility must provide to meet the consistent, ongoing needs of its customers. Historically, this steady demand was met by large power plants (like coal or nuclear) that ran continuously. Today, with more renewable energy, this minimum demand can be met by a flexible mix of various power sources, rather than relying solely on specific “baseload plants”.

  • Baseload capacity:  The generating equipment normally operated to serve loads on an around-the-clock basis.
  • Baseload plant:  A plant, usually housing high-efficiency steam-electric units, which produces electricity at an essentially constant rate and runs continuously. 
Battery Energy Storage System (BESS)

A technology that stores electrical energy in rechargeable batteries for later use. Batteries help stabilize the grid, manage energy demand, and increase the use of renewable energy.

Behind-the-meter

Any energy resource that provides energy directly to a home or business without passing through a utility company’s meter. Examples include rooftop solar and microgrids.

Economic dispatch

The mechanism for choosing the lowest cost energy option that meets energy needs, which gives cheaper renewable energy and battery storage an edge. 

  • Uneconomic dispatch – when a grid operator/utility chooses a higher-priced energy option, or above market-rate source, to meet electricity needs. This has emerged as a significant problem in areas where United States utilities are operating coal plants that can’t compete on cost with gas-fueled facilities and renewables. This practice allows utilities to continue to collect the costs of fuel and operations from customers to pay off their investment in the power plant.
Effective Load Carrying Capability (ELCC)

Measurement used to calculate how much an energy resource–such as a wind farm or solar array–contributes to the overall reliability of the grid. It assesses the resource’s ability to meet electricity demand, particularly during peak usage periods, and is especially useful for variable renewable energy sources whose output depends on factors like weather conditions. 

Energy efficiency

Measures that reduce electricity use in a home or business. These measures include replacing inefficient heating and air conditioners with heat pumps, adding attic insulation, and sealing ducts and foundation, walls, roof, windows, and doors of buildings. It also includes replacing energy-intensive appliances with more efficient ones. These measures can provide energy savings, improve comfort, and increase property values.

Energy-only interconnection approaches

Connecting new generation to the grid with minimal transmission upgrades and managing impacts through operational strategies rather than extensive upfront infrastructure investments. This approach, often referred to as “connect and manage,” prioritizes adding generation capacity quickly while relying on the grid operator to manage any resulting operational constraints. It requires new resources to risk curtailment (where the generator is asked to stop supplying power to the grid when supply is too high). The process has allowed Texas’ ERCOT to connect record numbers of new clean projects in the last several years significantly faster than other regions. 

ERCOT

The Electric Reliability Council of Texas serves as an independent system operator (ISO), managing the flow of electrical power over transmission infrastructure in the state of Texas.

Essential reliability services

A combination of automated and manual controls grid operators adjust to maintain grid reliability by ensuring a balance between supply (generation) and demand (load). They generally consist of three main aspects:

  • frequency response – short-term adjustments to maintain the grid’s oscillations at 60 hz)
  • balancing – related to frequency response but on longer time frames, to, for e.g., plan for energy resource outages due to maintenance, and 
  • voltage control – involves magnetic waves to allow for the movement of watts of energy
National Association of Regulatory Utility Commissioners (NARUC)

A non-profit organization that represents state public service commissions, which regulate essential utility services like energy, telecommunications, and water. Its stated aim is to improve the quality and effectiveness of public utility regulation. It has eight committees:

  1. Consumer Affairs
  2. Critical Infrastructure
  3. Electricity
  4. Energy Resources & Environment
  5. Gas
  6. International Relations
  7. Telecommunications
  8. Water

It also has a task force focused on Innovation.

NERC

Non-profit organization that operates to assure the effective and efficient reduction of risks to the reliability and security of the grid. It oversees six regional reliability entities and encompasses all of the interconnected power systems of Canada and the contiguous United States, as well as a portion of the Mexican state of Baja California. Its responsibilities include working with all stakeholders to develop standards for power system operation, monitoring and enforcing compliance with those standards, assessing resource adequacy, and providing educational and training resources as part of an accreditation program. NERC also investigates and analyzes the causes of significant power system disturbances in order to help prevent future events and produces reports about the near and long-term reliability forecast.

Notice of Proposed Rulemaking (NOPR)

A document used by government agencies to announce a potential new rule or amendment to an existing one. This is an official part of the law-making process, allowing public comment before the rule is finalized. The acronym is frequently used by the Federal Energy Regulatory Commission (FERC).

NREL

A government-owned, contractor-operated facility, funded and overseen by the United States Department of Energy’s (DOE) Office of Energy Efficiency and Renewable Energy (EERE). It specializes in the research and development of renewable energy, energy efficiency, energy systems integration, and sustainable transportation.

NYISO

New York ISO

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