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.
Technology that provides the interface between the grid and energy sources like solar panels, wind turbines, and energy storage, converting direct current to alternating current (which is how electricity is delivered in the United States). It is used to convert power output from solar cells, batteries, and wind turbines into power that can be injected into the grid.
A power generation or storage device (such as a battery) that connects to the electrical grid through an inverter, a power electronic device that converts direct current (DC) to alternating current (AC). These resources, including solar photovoltaic (PV) systems, wind turbines, and battery energy storage systems, are increasingly important for grid stability.
ISO New England
Midcontinent Independent System Operator, serves northern Midwest, southeast, and parts of Canada
Wind turbines erected in bodies of water that harness the power of wind, converting it into electricity that is then transmitted to the mainland to power homes and businesses. Offshore wind farms are considered a renewable energy source.
The real-time balancing of energy supply and demand to maintain frequency and voltage within safe operating limits. It is the shorter-term dimension of reliability and requires regular monitoring and control of the entire grid. It includes the ability to quickly respond to sudden changes, like the loss of a major power plant or transmission line, and to handle normal variations in supply and demand.
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.
