Glossary

Base-Load Unit

A power generating facility that is intended to run constantly at near capacity levels to provide the basic amount of electric power needed year-round.

California Energy Commission (CEC)

The state agency established by the Warren-Alquist State Energy Resources Conservation and Development Act in 1974 responsible for energy policy. The Energy Commission's five major areas of responsibilities are:

1. Forecasting future statewide energy needs
2. Licensing power plants sufficient to meet those needs
3. Promoting energy conservation and efficiency measures
4. Developing renewable and alternative energy resources, including providing assistance to develop clean transportation fuels
5. Planning for and directing state response to energy emergencies

California Independent System Operator (CAISO)

A neutral operator responsible for maintaining instantaneous balance of the grid system. The CAISO performs its function by controlling the dispatch of flexible plants to ensure that loads match resources available to the system.

California Public Utilities Commission (CPUC)

A state agency created by constitutional amendment in 1911 to regulate the rates and services of more than 1,500 privately owned utilities and 20,000 transportation companies. The CPUC is an administrative agency that exercises both legislative and judicial powers; its decisions and orders may be appealed only to the California Supreme Court. The major duties of the CPUC are to regulate privately owned utilities, securing adequate service to the public at rates that are just and reasonable both to customers and shareholders of the utilities. The CPUC also provides electricity and natural gas forecasting, and analysis and planning of energy supply and resources.

Capacity

The capability or power of an electric generating plant. Also, the total amount of electricity a power line is able to transport at any given time.

Combined Cycle

In a combined cycle power plant, a gas turbine generator generates electricity and the waste heat is used to make steam to generate additional electricity via a steam turbine; this last step enhances the efficiency of electricity generation.

Community Choice Aggregation (CCA)

As defined by Assembly Bill 117, CCA permits any city, county or city and county to aggregate the electric loads of residents, businesses and municipal facilities to facilitate the purchase and sale of electrical energy.

Conservation

Steps taken to cause less energy to be used than would otherwise be the case. These steps may involve improved efficiency, avoidance of waste, reduced consumption, etc. They may involve installing equipment (such as a computer to ensure efficient energy use), modifying equipment (such as making a boiler more efficient), adding insulation, changing behavior patterns, etc.

[ Back to Top ]

Demand

The amount of electricity drawn from an electric system at a given time, expressed in kilowatts or megawatts.

Distributed Generation (DG)

Small, modular, decentralized, grid-connected or off-grid energy systems located in or near the place where energy is used.

Distribution System

The substations, transformers and lines that convey electricity from high-power transmission lines to neighborhoods and communities. This system of wires is comprised of sets of three or four wires which can be suspended or buried underground. The voltage on distribution lines ranges from 4,000 to 12,000 volts and is further stepped down with transformers to a customer use level ranging from 480 to 120 volts.

Greater Fresno Area

The 6-county area comprised of Merced, Mariposa, Madera, Fresno, Kings and Tulare counties.

[ Back to Top ]

Load

The amount of electric power supplied to meet one or more end user's needs.

Megawatt (MW)

One thousand kilowatts (1,000 kW) or one million (1,000,000) watts. One megawatt is enough energy to power 1,000 average California homes.

Natural Gas

Hydrocarbon gas found in the earth, composed of methane, ethane, butane, propane and other gases.

[ Back to Top ]

Path 15

A system of three 500-kilovolt lines that used to narrow down to two lines for an 83-mile stretch through the Central Valley is one of the major North-South transmission lines in California. In order to alleviate congestion on Path 15, Western Area Power Administration, PG&E and Trans-Elect built a third 500-kV transmission line parallel to the existing Path 15 transmission facilities and upgraded other associated transmission facilities. The Path 15 Upgrade was completed in December 2004 and added 1,500 megawatts of transmission capacity.

Peaking Unit

A power generating station that is used to produce extra electricity during peak load times. Daily electric peaks on weekdays occur in late afternoon and early evening. Annual peaks occur on hot summer days.

Reliability

Electric system reliability has two components: adequacy and security. Adequacy is the ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers at all times, taking into account scheduled and unscheduled outages of system facilities. Security is the ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities.

Renewable Energy

Resources that constantly renew themselves or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or less-developed sources such as tidal power, sea currents and ocean thermal gradients.

Renewable Portfolio Standard (RPS)

A policy set by federal or state governments that a percentage of the electricity supplied by generators be derived from a renewable source.

[ Back to Top ]

Transmission System

The electricity produced at generating stations is connected to a system of wires called the transmission system. This interconnected "spider web" of wires carries electricity across cities, counties, states, and even countries through sets of three wires. The transmission system can carry electricity vast distances because it is done at very high voltages (69,000 to 500,000 Volts).

[ Back to Top ]