In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of…

Energy switching services are companies that have come to exist since the EU began deregulating the gas and electricity markets, to open them to competition, in 1996. Progress has been uneven across member countries, but in the UK there is now open competition among suppliers.

Centrica plc is a British multinational energy and services company with its headquarters in Windsor, Berkshire, England. It is the largest supplier of gas to domestic customers in the United Kingdom, and one of the largest suppliers of electricity, operating under the trading names British Gas in England and…

Robin Hood Energy was a not-for-profit energy company launched in September 2015 by Nottingham City Council as a competitor to the "big six" energy suppliers in the United Kingdom. The company supplied gas and electricity nationally to homes and businesses until September 2020, when its customer accounts were sold to…

SolarCity Corporation was a publicly traded company headquartered in Fremont, California, that sold and installed solar energy generation systems as well as other related products and services to residential, commercial, and industrial customers. The company was founded on July 4, 2006, by Peter and Lyndon Rive, the…

OVO Energy is an energy supplier based in Bristol, England. It was founded by Stephen Fitzpatrick and began trading energy in September 2009, buying and selling electricity and gas to supply domestic properties throughout the UK. By June 2017, OVO had 680,000 customers, an increase of 10,000 over the previous year,…

Renewable energy in Germany comes mainly from wind power, solar power and biomass and is a central component of the country's Energiewende. In 2025, renewable sources accounted for 23.8% of Germany's gross final energy consumption.

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…

Solar power in Switzerland has demonstrated consistent capacity growth since the early 2010s, influenced by government subsidy mechanisms such as the implementation of the feed-in tariff in 2009 and the enactment of the revised Energy Act in 2018. In 2025, solar power contributes nearly to 8 TWh of generation to the…

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.