Energy losses across the hydrogen lifecycle
Turning electricity into usable energy via hydrogen involves multiple conversion steps, each with efficiency losses. Understanding where energy is lost helps decide the best use cases for hydrogen.
Key stages and efficiencies
- Electrolysis: converting electricity to hydrogen typically achieves 60–80% efficiency (electrical energy to chemical energy), meaning roughly 20–40% of the electricity is lost.
- Compression or liquefaction: preparing hydrogen for storage or transport consumes additional energy, often 5–15% depending on pressure and method.
- Transport and storage losses: losses come from boil-off (for liquefied hydrogen), compression energy, and possible leakage; these are usually modest but depend on technology.
- Conversion back to electricity: fuel cells convert hydrogen back to electricity at roughly 40–60% efficiency; gas turbines are 30–40% efficient when used to generate power.
Overall round-trip efficiency
When using hydrogen as long-term storage—electricity -> hydrogen -> electricity—the overall round-trip efficiency is typically in the 20–40% range, depending on technologies used. This is lower than battery-based storage, which can deliver 70–90% round-trip efficiency, but hydrogen offers advantages for long-duration and seasonal storage where batteries are less economical.
Implications for applications
- Short-duration grid storage and passenger cars: batteries often win due to higher round-trip efficiency.
- Long-duration storage, industrial feedstock, high-temperature heat, and heavy transport: hydrogen can be competitive because it provides high energy density and flexibility despite conversion losses.
Improving efficiency
Technological improvements in electrolyzers and fuel cells, better system integration, and waste heat recovery can raise effective efficiencies. Selecting hydrogen for applications aligned with its strengths—where direct electrification is impractical—helps balance the energy trade-offs.