Another option with chemical energy storage is to convert electricity into basic chemical materials (methanol) or liquid fuels (power-to-liquid). These liquid fuels would be particularly useful in transport segments requiring high energy densities such as aviation (Fig. 11). Fig. 11.
Thermochemical energy storage is quite a new method and is under research and development phase at various levels (Prieto, Cooper, Fernández, & Cabeza, 2016 ). In this technique, the energy is stored and released in the form of a chemical reaction and is generally classified under the heat storage process.
Chemical energy is stored in the chemical bonds of atoms and molecules, which is released when a chemical reaction occurs, and the substance is often changed into entirely different substance. Currently, chemical fuels are the dominant form of energy storage both for electric generation and for transportation.
The storage of energy through reversible chemical reactions is a developing research area whereby the energy is stored in chemical form . In chemical energy storage, energy is absorbed and released when chemical compounds react.
Alternatively, heat can be stored by directing thermal energy to an endothermic chemical reaction. In this reaction, a thermochemical absorbs the energy and splits into separate substances, which can be stored until the energy is needed again.
Thermochemical heat storage works on the notion that all chemical reactions either absorb or release heat; hence, a reversible process that absorbs heat while running in one way would release heat when running in the other direction. Thermochemical energy storage stores energy by using a high-energy chemical process.