Electricity is supplied to homes and businesses in the United States in the form of alternating current, and frequency is the rate at which an alternating current changes direction, as measured in hertz (Hz). Across the power grid there is a consistent frequency which in the United States is 60 Hz. 

The ability of the grid to react to a change in

the frequency to bring it back to the normal operating frequency, which is 60 Hz in the United States

• Inertial response refers to the injection of stored energy, such as battery energy, into the electricity grid to slow down a decline in frequency. 
• Primary frequency response – The first line of defense against frequency fluctuations that could destabilize the grid. It takes the form of immediate, automatic adjustments in power output by generators and loads in response to frequency deviations in the electric grid.
• Fast frequency response consists of the combined inertial response and primary frequency response. It injects energy in the seconds immediately following a disturbance to slow frequency decline and establishes the minimum frequency (called the nadir).
• Secondary frequency response works on a slightly longer time frame than primary frequency response, on the order of 5-15 minutes. It maintains grid frequency and allows for scheduled energy transfers between balancing authorities, which include utilities, regional transmission operators, and other grid management entities.

The brief periods when electricity consumption is at its highest, often driven by factors like extreme weather or heat events. This is the highest amount of electricity demand for which a grid operator needs to plan.

A power plant that is designed to quickly ramp up and provide electricity during periods of high energy demand, such as during hot summer afternoons or cold winter evenings, to meet the increased needs of households and businesses. These plants generally only run during these peak events to supplement regular power generation. 

A regulatory tool that ties a portion of utilities’ earnings to the utilities’ performance on desired regulatory outcomes, offering utilities opportunities to create the programs and services needed to advance emerging priorities.

The conversion of light into electricity at the junction of two substances exposed to light. A photovoltaic system employs solar modules, each comprising a number of solar cells, which generate electrical power.

Pennsylvania-New Jersey-Maryland Interconnection- services 13 states in Midatlantic and Midwest region

The rate of transfer of energy. It’s essentially how quickly energy is being used or converted from one form to another in an electrical circuit. Power is measured in watts (W), which represents one joule (J) of energy per second.

A measure of how efficiently electrical power is being used. It shows how much of the total power flowing in a circuit is actually doing useful work (active power) versus being ”wasted” as reactive power. A power factor closer to 1 means higher efficiency and fewer losses.

Sometimes also called a Public Service Commission (PSC), is a state-level governmental agency that regulates utilities like electricity, gas, and water. PUCs ensure that these essential services are provided fairly, reliably, and at reasonable prices, often by overseeing monopolies and protecting consumers.