Chemical energy storage and how it differs from other forms of energy storage will be discussed. We will consider the fundamental requirements of a chemical energy store system in order to select possible chemical solutions. Energy densities will be compared to other forms of energy storage for context. Material and energy balances for overall chemical energy storage processes will be employed in order to gain insight into important issues that need to be considered when designing a chemical energy store. Simple back-of-the-envelope calculations will be used to develop ideas. We will study the topical example of methanol production from combustion flue gas as a case study as well as the example of ammonia as a hydrogen carrier. The importance of handling and distribution of chemical energy storage media will be emphasised. Optimal strategies for energy integration using tools such as pinch technology will be discussed.

Our aim is to show that chemical energy storage can serve the additional purpose of making overall energy conversion processes more efficient by allowing us to move waste-heat off e.g. vehicles to stationary locations. This comes with a very significant thermodynamic benefit.