Liquid fuels Natural gas Coal Nuclear Renewables (incl. hydroelectric) Source: EIA, Statista, KPMG analysis Depending on how energy is stored, storage technologies can be broadly divided into the followin.
[pdf] The latest study from this group presents a groundbreaking approach that combines compressed-air energy storage (CAES) with geothermal energy derived from depleted oil and gas wells, showcasing a promising pathway to enhance efficiency and reduce operational costs in energy storage.
[pdf] A decentralized variable electric motor and fixed pump (VMFP) system with a four-chamber cylinder is proposed for mobile machinery, such that the energy efficiency can be improved by hydro-pneumatic energ.
[pdf] 
