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).
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.
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.
For electricity infrastructure, like power lines and generating facilities, these requirements involve a range of considerations, including safety, environmental impact, and community engagement. Specific regulations vary by location and project type, but generally include distance requirements from existing infrastructure, environmental assessments, and engagement with landowners and stakeholders.
The conversion of sunlight into electricity using photovoltaics (PV) or solar thermal technologies. It’s a renewable energy source that is becoming increasingly important in the global energy landscape due to its sustainability and decreasing costs.
Refers to the real-time wholesale cost of electricity that fluctuates based on supply, demand, weather, and grid conditions.
Southwest Power Pool
Generators with turbines rotating in sync with the grid frequency. They include large-scale thermal (coal and gas) and hydropower plants.
Measure of the rate of energy transfer over a unit of time, with one watt equal to one joule (J) per second.
A form of renewable energy that uses the kinetic energy of wind to generate electricity. It involves capturing the wind’s energy through turbines, which then convert this mechanical energy into electricity. Modern wind power generation primarily relies on wind turbines, often grouped into wind farms, connected to the electrical grid.
The increase in energy demand during the winter months, usually due to heating needs. This can lead to higher energy prices and bills for a number of reasons, including:
