Hydrogen production
Power plant
Stack
H
GT
HRSG
Hydrogen storage
Condensate
Condenser
Electrolysis
G
Turbine + generator
Condensate
Figure 3 Hydrogen production – power-to-gas storage
considerations (preventing leaks and avoiding metal embrittlement) also mean infrastructure must be specifically designed for hydrogen use. Despite these challenges, hydrogen is seen as a key piece of a future carbon-free energy system. Its strength is in tackling the longest-duration storage needs – multi-week or seasonal gaps – especially in places where geology and infrastructure align to enable large- scale hydrogen use. Key points – hydrogen: ● Efficiency: ~35% round-trip (low; significant energy losses in conversion). ● Best use: Long-duration and seasonal storage (days, weeks, or months of energy reserve). ● Pros: Massive storage capacity potential (TWh-scale), especially in underground caverns with no energy loss over time; significant industry and government investment is driving further improvements. ● Cons: Low overall efficiency; high upfront capital costs for electrolysers and fuel conversion equipment; effective large-scale storage often depends on suitable geology (salt caverns) or requires costly tank systems; handling hydrogen demands new infrastructure and strict safety measures. Methanol: a liquid energy storage solution Methanol (CH₃OH), a simple liquid alcohol, is gaining attention as an energy storage medium and as a way to transport renewable energy.
In the context of grid storage, methanol serves as a chemical battery: surplus electricity is used to produce hydrogen (via electrolysis), that hydrogen is then combined with carbon dioxide to synthesise methanol, and the liquid methanol is stored in tanks. When electricity is needed later, the methanol can be converted back to power by either burning it in a generator/turbine or by reforming it to hydrogen for use in a fuel cell. The carbon dioxide released when methanol is used can be captured and recycled to produce more methanol, making the whole loop potentially carbon-neutral. Essentially, methanol storage is a way to bottle up renewable electricity into a liquid fuel that can be stockpiled and transported as needed. One of methanol’s biggest advantages is its physical form: it is a liquid at ambient temperature and pressure, much like gasoline or ethanol. This means it can be handled with the well-established infrastructure already used for liquid fuels – tanks, pipelines, rail cars, trucks, and ships. In fact, methanol is already produced and transported globally on a large scale using standard fuel infrastructure. There is growing interest in making ‘green methanol’ from renewables (for example, as a cleaner shipping fuel), so the logistics and know-how for handling methanol are well established. For the power grid, this translates to a storage medium that can be deployed anywhere (no special geology needed) in large volumes at relatively
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