Power-to-Gas Efficiency Calculator

Because a power-to-gas-to-power system chains four separate lossy conversion stages -- electrolysis, compression, storage loss, and fuel-cell reconversion -- and their efficiencies multiply together rather than average. Even if each individual stage is reasonably efficient on its own, compounding four stages produces a lower overall figure than a battery's single charge/discharge cycle, which is commonly cited around 85-92% round-trip.

Round-trip efficiency isn't the only thing that matters for grid-scale storage -- hydrogen can be stored for weeks or months with comparatively little additional cost per unit of stored energy, which suits long-duration and seasonal storage needs that batteries handle poorly due to self-discharge and the cost of scaling battery capacity for very long storage durations. The efficiency disadvantage is a real tradeoff for hydrogen's storage-duration advantage, not a sign it's obsolete for every use case.

Since all four stage efficiencies multiply together, improving any one of them raises the overall round-trip figure — but electrolyzer and fuel-cell efficiency generally have the widest real-world ranges (roughly 60-80% and 30-70% respectively) compared to compression and storage loss, which are usually higher and narrower, so improvements to electrolyzer or fuel-cell technology typically move the overall figure the most.

No -- this calculator models only the electrolysis-to-storage-to-fuel-cell conversion chain at a single location. Transporting hydrogen (by pipeline, truck, or otherwise) to a separate point of use adds its own energy cost and potential losses that aren't captured in this round-trip efficiency figure.