Compressed-air energy storage
Advancements in adiabatic CAES involve the development of high-efficiency thermal energy storage systems that capture and reuse the heat generated during compression.
Recent developments in isothermal CAES focus on advanced thermal management techniques and materials that maintain constant air temperatures during compression and expansion, minimizing energy losses and improving system efficiency.
[17] The storage vessel is often a cavern created by solution mining (salt is dissolved in water for extraction)[18] or by using an abandoned mine; use of porous and permeable rock formations (rocks that have interconnected holes, through which liquid or air can pass), such as those in which reservoirs of natural gas are found, has also been studied.
[19] Compressed-air energy storage can also be employed on a smaller scale, such as exploited by air cars and air-driven locomotives, and can use high-strength (e.g., carbon-fiber) air-storage tanks.
Unlike lithium-ion batteries, which require the extraction of finite resources such as lithium and cobalt, CAES has a minimal environmental footprint during its lifecycle.
Inappropriate siting or mismanagement during construction can lead to disruptions in local ecosystems, land subsidence, or groundwater contamination.
Additionally, repurposing depleted natural gas fields or other geological formations for air storage can mitigate environmental impacts and extend the usefulness of existing infrastructure.
Government incentives and declining costs of advanced components, such as high-efficiency compressors and turbines, are further enhancing the economic feasibility of CAES.
Countries like Germany and the United States have implemented various incentives, including tax credits and grants, to promote energy storage technologies.
Environmental impact assessments, land use approvals, and safety standards for high-pressure storage systems can delay or increase costs for CAES projects.
As renewable energy adoption accelerates, policies aimed at addressing intermittency challenges will likely prioritize grid-scale solutions like CAES.
[23] Cities such as Paris, France; Birmingham, England; Dresden, Rixdorf, and Offenbach, Germany; and Buenos Aires, Argentina, installed such systems.
Victor Popp constructed the first systems to power clocks by sending a pulse of air every minute to change their pointer arms.
[24] As of 1896, the Paris system had 2.2 MW of generation distributed at 550 kPa in 50 km of air pipes for motors in light and heavy industry.
[23] The systems were the main source of house-delivered energy in those days and also powered the machines of dentists, seamstresses, printing facilities, and bakeries.
The first utility-scale diabatic compressed-air energy storage project was the 290-megawatt Huntorf plant opened in 1978 in Germany using a salt dome cavern with a capacity of 580 megawatt-hours (2,100 GJ) and a 42% efficiency.
[39] In 2010, the US Department of Energy provided $29.4 million in funding to conduct preliminary work on a 150-MW salt-based project being developed by Iberdrola USA in Watkins Glen, New York.
[39][40] The first adiabatic project, a 200-megawatt facility called ADELE, was planned for construction in Germany (2013) with a target of 70% efficiency by using 600 °C (1,112 °F) air at 100 bars of pressure.
[44] The European-Union-funded RICAS (adiabatic) project in Austria was to use crushed rock to store heat from the compression process to improve efficiency (2020).
This advantage is in addition to the low cost of constructing the gas storage system, using the underground walls to assist in containing the pressure.
It is technically challenging to design air engines to maintain high efficiency and sufficient power over a wide range of pressures.
Compressed air can transfer power at very high flux rates, which meets the principal acceleration and deceleration objectives of transportation systems, particularly for hybrid vehicles.
Compressed air systems have advantages over conventional batteries, including longer lifetimes of pressure vessels and lower material toxicity.
Life cycle assessment addresses the question of overall emissions from a given energy storage technology combined with a given mix of generation on a power grid.
Typically, the main claimed advantages are no roadside pollution, low cost, use of cooking oil for lubrication, and integrated air conditioning.
Bosch and PSA Peugeot Citroën have developed a hybrid system that uses hydraulics as a way to transfer energy to and from a compressed nitrogen tank.
An up-to-45% reduction in fuel consumption is claimed, corresponding to 2.9 L / 100 km (81 mpg, 69 g CO2/km) on the New European Driving Cycle (NEDC) for a compact frame like Peugeot 208.
[57] Air engines have been used since the 19th century to power mine locomotives, pumps, drills, and trams, via centralized, city-level distribution.
The ISEP was an innovative, 270-megawatt, $400 million compressed air energy storage (CAES) project proposed for in-service near Des Moines, Iowa, in 2015.
The cool compressed air regains the heat stored in the stones when released back through a surface turbine, leading to higher overall efficiency.
