California ISO
The maximum amount of power an energy source can physically produce (measured in megawatts/MW), or when referring to an electrical grid, the total amount of electricity that power plants connected to the grid are capable of producing. It’s essentially the total potential output of all the electricity sources, like coal, nuclear, hydro, wind, and solar plants. Meanwhile, energy is the actual output of a source over a particular time period.
Generally, participants submit sealed bids to offer capacity at specific prices. The auction ends when the total capacity offered matches the region’s needs, and a single clearing price is set for all commitments.
An energy source that generates electricity with zero- or extremely low-carbon emissions, and can do so when needed, regardless of weather conditions. They include enhanced geothermal energy and advanced nuclear technologies. They also can include solar or wind paired with battery storage to provide on-demand power supply regardless of weather conditions or time of day.
Refers to a regulatory approach for connecting new power generators to the electrical grid, notably used in Texas (ERCOT). This approach allows new generators to connect expeditiously with minimal upfront transmission upgrades. However, the grid operator retains the right to curtail their output if transmission constraints arise. This contrasts with approaches where developers pay for upgrades prior to connection. (see Energy-only interconnection approaches)
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).
The mechanism for choosing the lowest cost energy option that meets energy needs, which gives cheaper renewable energy and battery storage an edge.
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.
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.
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.
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.
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:
Fuel cell that carries energy generated from another source. It can be used in fuel cells to generate electricity with water as the only byproduct, or it can be burned for heat. Hydrogen can be produced from a variety of sources–renewable energy such as solar or wind, or gas plants, nuclear, and other energy sources–which dictate whether it can be considered “clean” or not.
Midcontinent Independent System Operator, serves northern Midwest, southeast, and parts of Canada
Power that does not perform useful work but is used to establish and maintain electromagnetic fields that are needed to generate, transmit, and convert electric power in the alternating current network. A shortage of reactive power can cause voltage to decline. (See also: voltage support)
A characteristic of the whole electricity system to describe its ability to consistently deliver electricity to consumers without interruption, even through grid disturbances. Reliability comes down to having sufficient generating resources to meet demand and a functional operational grid system.
An agreement initiated by an RTO or ISO with a power plant, keeping it in operation temporarily for reliability purposes.
The ability of the grid to ride through extreme events, recover quickly, and support other critical systems (e.g., transportation, health care, public safety etc.).
An assessment of whether the current or projected resource mix is sufficient to meet capacity and energy needs for a particular grid. The resource mix includes all resources able to provide capacity and energy to the system. Adequacy assessments are used to identify potential shortfalls in the availability of resources across different time frames; from long-term planning (5 to 20+ years) to seasonal and day-ahead assessments.
(see also: ISO) – A non-profit organization that manages the electricity transmission system in a specific region, ensuring reliable and efficient electricity delivery. RTOs operate the high-voltage electricity grid, facilitating the movement of power from generating plants to substations and ultimately to consumers. They also oversee competitive wholesale electricity markets.
