Compact efficient high density energy storage over time

Thermochemical storage holds the promises of compactness (high energy density) and negligible heat losses during prolonged storage. The reason for the latter is that the energy is stored in a chemical or physical reaction and the components are stored separately. Once the components are brought together, the heat is released again, as illustrated below.

Heat stored in reversible reactions (the material is ‘charged’) or released (the material is ‘discharged’)

The compactness (high energy density) of thermochemical storage is illustrated by the table below, comparing the energy density of two types of thermochemical materials with that of water based storage.

Energy density of thermochemical materials compared to the (sensible) heat stored in water.