Energy Storage by CO2 Methanization and Energy Carrying Compounds: A Thermodynamic Comparison

Reconstructing current energy infrastructures dominated by fossil fuels towards a high share of renewable energy requires a drastic extension of energy storage capacities. Common storage technologies like compressed air or pumped hydro are either limited in capacity or have to face low efficiencies. A promising alternative is proposed with the use of energy carrying compounds for hydrogen storage. This route is shown to offer the possibility to combine high process chain efficiency with lossless energy storage for stationary and mobile applications. In this article, efficiencies for energy storage by methane and energy transport substances are calculated and compared to each other.