Green hydrogen as the key to long-term energy storage

The global energy system in undergoing a major transformation toward decarbonization.
Integrating renewable sources like solar and wind has introduced new challenges for energy storage. Solar panels generate electricity only when the sun shines, and wind turbines spin only when the wind blows. This variability demands reliable energy storage solutions to bridge the gap between supply and demand across minutes, hours, days, or seasons.
While batteries have proven effective for short-term energy storage, green hydrogen is emerging as a promising vector for long-term storage and grid stability.

Lithium-ion batteries dominate today’s energy storage market. Their efficiency, responsiveness, and scalability make them ideal for short-term applications, such as balancing grid frequency or storing excess solar energy for evening use.
However, batteries face significant limitations: limited energy density, degradation over time, and high upfront costs, making them unsuitable for long-term storage.

Green hydrogen offers a compelling alternative for long-duration and seasonal energy storage. Produced through electrolysis a process where water is split into hydrogen and oxygen using renewable electricity, green hydrogen is virtually emissions-free. 
When surplus renewable energy is available, it can be converted into hydrogen and stored for later use. This stored hydrogen can then be reconverted into electricity using fuel cells or gas turbines, or used directly in industrial hard-to-abate processes.

Unlike batteries, hydrogen does not self-discharge and can be stored in large quantities for months in underground caverns, pressurized tanks, or pipelines. This makes it especially valuable for managing seasonal mismatches in energy supply and demand, such as storing excess summer solar generation for use during winter.

The debate over batteries versus hydrogen often misses the point: they serve different purposes.

• Batteries are ideal for intra-day balancing and quick power delivery. They can respond to grid fluctuations within milliseconds and are highly efficient.

• Green hydrogen is less efficient, but it excels in capacity and duration. It can store vast amounts of energy for weeks or even seasons, something that would be prohibitively expensive with batteries alone.

A resilient, decarbonized energy system will likely rely on both technologies: batteries to manage short-term fluctuations, and green hydrogen as a strategic reserve, supporting heavy industry and serving as an energy vector in sectors difficult to electrify.

Despite its advantages, green hydrogen still faces economic and infrastructure challenges:

• Electrolyzers remain expensive;

• Hydrogen storage, transport, and distribution networks are not yet fully developed.

However, as technology advances and economies of scale are achieved, these barriers are expected to diminish.

Governments and industries are already investing heavily in hydrogen. The European Union, for instance, has made green hydrogen a cornerstone of its climate strategy, while pilot projects worldwide are testing its use in power generation, district heating, and transportation.

Thanks to its ability to store renewable energy over the long term, green hydrogen complements the speed and efficiency of batteries, making it a key element of the energy transition.
Together, these technologies can build a flexible, resilient, and zero-emission energy system, ready to meet the challenges of the 21st century.