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).
These incentivize customers to reduce, increase, or shift their electricity consumption in response to price spikes or grid reliability signals. Most programs encourage utility customers primarily through price incentives to shift electricity consumption from hours of high demand (relative to energy supply) to hours when energy supply is plentiful (relative to demand).
These encompass strategies and programs designed to influence electricity consumption patterns on the customer side of the meter. These initiatives aim to moderate electricity demand through methods such as financial incentives for energy conservation and energy efficiency measures, like improved insulation or the adoption of energy-efficient appliances.
Refers to electricity generation resources that power grid operators can control and adjust on demand to meet changing electricity needs. These include nuclear, hydropower, battery storage, and thermal power plants.
Small-scale energy generation and storage technologies located near the point where the energy is used, rather than at a centralized power plant. These resources–such as solar microgrids, rooftop solar, and battery storage–can be used to enhance or replace traditional energy sources and can operate independently or be connected to the main grid.
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.
The ability of a piece of electrical equipment to stay connected to the grid through a short-term disturbance, thus helping keep the grid stable through the event. Inverter-based resources, such as photovoltaic solar arrays, wind turbines, and battery storage, can provide disturbance ride-through services, but require specific design of their control system to do so.
In energy regulation, it is a formal proceeding or official record initiated by a regulatory body (such as a Public Utilities Commission or the Federal Energy Regulatory Commission (FERC)) to address a specific issue or project. It serves as a repository for all submitted documents, evidence, and public comments.
A visual representation of how solar power generation impacts the daily electricity demand curve, particularly in regions with high solar adoption like California. It depicts a dip in net electricity demand during midday due to solar generation, followed by a steep increase in the evening as solar output decreases and demand peaks.
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.
An entity that is hired by an Independent System Operator (ISO) or Regional Transmission Organization (RTO) to oversee and assess the operations of the wholesale electricity market. Its primary role is to ensure fair and competitive market practices by monitoring market participant behavior and identifying potential market manipulation or design flaws.
A non-profit organization that manages the electricity grid and wholesale electricity markets within a specific geographic region. Its primary role is to ensure the reliable and efficient delivery of electricity, balancing supply and demand in real-time and overseeing fair competition among market participants.
In the context of the grid, it refers to the energy stored in the rotating machinery of generators, such as the turbines of a gas plant or hydropower station.
The turbines rotate at the same rate as the grid–60 cycles per second (hertz) in the United States–and help provide stability for the grid, particularly during spikes in power demand or other disturbances. If the power plant goes offline for any reason, the inertia of the turbines maintains the grid’s frequency for a window of time while another power source is brought online to replace the offline generator.
Certain types of renewable energy, such as wind and solar photovoltaic, do not use rotational generators, instead using electronic inverters. But these renewable technologies include electronic sensors that can respond to changes in frequency quickly, and can replace the need for rotational inertia.Synthetic inertia – Inertia provided without synchronous generators and refers to the transfer of active power into the grid from a grid-forming inverter. This type of inertia can provide the same, or even better, stabilization services as traditional inertia because it has an instantaneous effect.
The process of connecting new power sources, like renewable energy generators or energy storage systems, to the existing grid infrastructure. It involves integrating these new sources with the grid’s transmission and distribution networks, ensuring a stable and reliable flow of electricity.
The line in which power generation and transmission projects must wait after they have requested to connect to the electric grid. These queues are managed by grid operators like ISOs (Independent System Operators) or RTOs (Regional Transmission Organizations). Projects are evaluated for their impact on the grid and the necessary upgrades before they can connect and deliver electricity.
A power source whose availability and output fluctuate due to natural variations in its energy source. This means the power supply isn’t consistently available, often linked to weather conditions like wind speed, time of day, or season. Renewable energy output can be forecast and stored in battery systems to maintain grid reliability.
