Chemical energy storage

This chapter discusses the state of the art in chemical energy storage, defined as the utilization of chemical species or materials from which energy can be extracted immediately or latently through the process of physical sorption, chemical sorption, intercalation, electrochemical, or chemical transformation. Storing electricity directly in batteries or capacitors from wind and solar at scale is challenging because even the most advanced electrochemical or charge storage devices, such as lithium ion batteries or ultracapacitors, have relatively low volumetric energy densities compared with liquid fuels like diesel, gasoline, or liquid methane. Hydrogen as an energy carrier is arguably one alternative to replacing petroleum products for transportation and stationary applications, if it can be produced in large quantities by clean and renewable means. Other chemical storage through sorption or chemical transformation provides advantages and viable alternatives to mechanical or thermal energy storage.