Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in multiple forms including radiation, chemical, gravitational potential, electrical potential, electricity, elevated temperature, latent heat and kinetic. Energy storage involves converting energy from forms that are difficult to store to more conveniently or economically storable forms.
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power.
Solar thermal energy (STE) is a form of energy and a technology for harnessing solar energy to generate thermal energy for use in industry, and in the residential and commercial sectors. Solar thermal collectors are classified by the United States Energy Information Administration as low-, medium-, or high-temperature collectors. Low-temperature collectors are generally unglazed and used to heat swimming pools or to heat ventilation air. Medium-temperature collectors are also usually flat plates but are used for heating water or air for residential and commercial use.
The hydrogen economy is an umbrella term for the roles hydrogen can play alongside low-carbon electricity to reduce emissions of greenhouse gases. The aim is to reduce emissions where cheaper and more energy-efficient clean solutions are not available. In this context, hydrogen economy encompasses the production of hydrogen and the use of hydrogen in ways that contribute to phasing-out fossil fuels and limiting climate change.
Centrica plc is a British multinational energy and services company with its headquarters in Windsor, Berkshire. Its principal activity is the supply of electricity and gas to consumers in the United Kingdom and Ireland.
Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inexpensive or when demand is low, and later returned to the grid when demand is high, and electricity prices tend to be higher.
The methanol economy is a suggested future economy in which methanol and dimethyl ether replace fossil fuels as a means of energy storage, ground transportation fuel, and raw material for synthetic hydrocarbons and their products. It offers an alternative to the proposed hydrogen economy or ethanol economy, although these concepts are not exclusive. Methanol can be produced from a variety of sources including fossil fuels as well as agricultural products and municipal waste, wood and varied biomass. It can also be made from chemical recycling of carbon dioxide.
Thermal energy storage (TES) is the storage of thermal energy for later reuse. Employing widely different technologies, it allows surplus thermal energy to be stored for hours, days, or months. Scale both of storage and use vary from small to large – from individual processes to district, town, or region. Usage examples are the balancing of energy demand between daytime and nighttime, storing summer heat for winter heating, or winter cold for summer cooling. Storage media include water or ice-slush tanks, masses of native earth or bedrock accessed with heat exchangers by means of boreholes, deep aquifers contained between impermeable strata; shallow, lined pits filled with gravel and water and insulated at the top, as well as eutectic solutions and phase-change materials.
Carbon capture and storage (CCS) is a process in which a relatively pure stream of carbon dioxide (CO2) from industrial sources is separated, treated and transported to a long-term storage location. For example, the burning of fossil fuels or biomass results in a stream of CO2 that could be captured and stored by CCS. Usually the CO2 is captured from large point sources, such as a chemical plant or a bioenergy plant, and then stored in a suitable geological formation. The aim is to reduce greenhouse gas emissions and thus mitigate climate change. For example, CCS retrofits for existing power plants can be one of the ways to limit emissions from the electricity sector and meet the Paris Agreement goals.
Pico hydro is a term used for hydroelectric power generation of under 5 kW. These generators have proven to be useful in small, remote communities that require only a small amount of electricity – for example, to power one or two fluorescent light bulbs and a TV or radio in 50 or so homes. Even smaller turbines of 200–300 W may power a single home with a drop of only 1 metre (3.3 ft). Pico-hydro setups typically are run-of-stream, meaning that a reservoir of water is not created, only a small weir is common, pipes divert some of the flow, drop this down a gradient, and through the turbine before being exhausted back to the stream.
ARPA-E, or Advanced Research Projects Agency–Energy is a United States government agency tasked with promoting and funding research and development of advanced energy technologies. It is modeled after the Defense Advanced Research Projects Agency (DARPA).
A liquid nitrogen engine is powered by liquid nitrogen, which is stored in a tank. Traditional nitrogen engine designs work by heating the liquid nitrogen in a heat exchanger, extracting heat from the ambient air and using the resulting pressurized gas to operate a piston or rotary motor. Vehicles propelled by liquid nitrogen have been demonstrated, but are not used commercially. One such vehicle, Liquid Air, was demonstrated in 1902.
The National Grid covers most of mainland Great Britain and several of the surrounding islands, and there are interconnectors to Northern Ireland and to other European countries. Power is supplied to consumers at 230 volts AC with a frequency of 50 Hz. In 2023 about a third of electricity used in Britain was generated from fossil gas and two-thirds was low-carbon power. Wind generates the most low-carbon power, followed by nuclear some of which is imported from France. The government is aiming for greenhouse gas emissions from electricity in Britain to be net zero by 2035.
Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable energy sources, such as dammed hydroelectricity or bioenergy, or relatively constant sources, such as geothermal power.
Cryogenic energy storage (CES) is the use of low temperature (cryogenic) liquids such as liquid air or liquid nitrogen to store energy. The technology is primarily used for the large-scale storage of electricity. Following grid-scale demonstrator plants, a 250 MWh commercial plant is now under construction in the UK, and a 400 MWh store is planned in the USA.
Rakesh Agrawal is a chemical engineer known for contributions to separations, cryogenic gas separation and liquefaction, and for contributions to renewable energy including the conversion of biomass to chemicals and fuels, inorganic solar cell fabrication, and the synergistic use of solar energy. He is the Winthrop E. Stone Distinguished Professor of Chemical Engineering at Purdue University in West Lafayette, Indiana.
Younicos was a German-American technology company that developed and sold energy storage systems and control software. The company integrated battery technologies, power electronics and control software to create systems that respond to the energy management requirements of power networks of all sizes, including micro-grids.
Direct air capture (DAC) is the use of chemical or physical processes to extract carbon dioxide directly from the ambient air. If the extracted CO2 is then sequestered in safe long-term storage, the overall process will achieve carbon dioxide removal and be a "negative emissions technology" (NET).
Moorside clean energy hub is a proposal put forward on 30 June 2020 by two consortia, one led by EDF and the other by Rolls-Royce, to create an energy hub that would produce electricity and hydrogen through the use of nuclear power and renewable energy.
A Carnot battery is a type of energy storage system that stores electricity in thermal energy storage. During the charging process, electricity is converted into heat and kept in heat storage. During the discharging process, the stored heat is converted back into electricity.
