How efficient is the hydrogen energy cycle?
Short answer
The hydrogen energy cycle is usually much less efficient than a battery cycle when the goal is electricity-in and electricity-out. The losses occur during electrolysis, compression or storage, and conversion back to electricity.
Loss chain
Start with renewable electricity. Some is lost in the electrolyzer. More is used for compression or handling. More is lost in the fuel cell or generator. The delivered electricity can be far below the starting electricity.
Why use it anyway?
Efficiency is not the only metric. Hydrogen may still work when electricity would otherwise be curtailed, when storage time is very long, or when hydrogen also serves fuel or industrial demand.
Buyer calculation
Compare delivered kWh, not input kWh. If 100 kWh of surplus electricity returns far less useful electricity, the stored energy must solve a high-value problem.
Practical recommendation
Use batteries for efficient daily cycling. Use hydrogen only when the time scale, fuel value, or curtailment problem justifies the losses.
References
Related Articles
