Electricity sector of the United States
The United States has the second largest electricity sector in the world, with 4,430 Terawatt-hours of generation in 2025. In 2024 the industry earned $514b in revenue (1.8% of GDP) at an average price of $0.129/kWh.
Power purchase agreement
A power purchase agreement (PPA), or electricity power agreement, is a long-term contract between an electricity generator and a customer, usually a utility, government or company. PPAs may last anywhere between 5 and 20 years, during which time the power purchaser buys energy at a pre-negotiated price.
Geothermal energy in the United States
Geothermal energy in the United States was first used for electric power production in 1960. The Geysers in Sonoma and Lake counties, California was developed into what is now the largest geothermal steam electrical plant in the world, at 1,517 megawatts.
Denver Federal Center
The Denver Federal Center, in Lakewood, Colorado, is part of the General Services Administration (GSA) and is home to about 6,200 employees of agencies of the federal government of the United States. The center encompasses an area of about 670 acres (2.7 km2) and has 90 buildings with over 4 000 000 square feet (370…
Solar water heating
Solar water heating (SWH) is heating water by sunlight, using a solar thermal collector. A variety of configurations are available at varying cost to provide solutions in different climates and latitudes.
Solar power in Spain
Spain is one of the first countries to deploy large-scale solar photovoltaics, and is the world leader in concentrated solar power (CSP) production. Spain is also one of the European countries with the most hours of sunshine.
Solar power in the United Kingdom
Solar power has a growing role in electricity production in the United Kingdom, contributing around 6.4% of the UK's annual power generation in 2025. As of 2025, on sunny days, it provides over 30% of the UK's power consumption at times.
Solar cell
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by using the photovoltaic effect. It is a type of photoelectric cell, a device whose electrical characteristics (such as current, voltage, or resistance) vary when it is…
Renewable energy
Renewable energy (also called green energy) is energy made from renewable natural resources that are replenished on a human timescale. The most widely used renewable energy types are solar energy, wind power, bioenergy/biomass, and hydropower.
Renewable energy in California
California produces more renewable energy than any other state in the United States except Texas. In 2018, California ranked first in the nation as a producer of electricity from solar, geothermal, and biomass resources and fourth in the nation in conventional hydroelectric power generation.