Environmental Science and Engineering | Plant Science
Hydrogen storage solution could lie in lakes
Plastic pipes installed in deep water could stockpile gas, helping the world move away from fossil fuels.

Hydrogen is a clean-burning fuel that could help to reduce fossil fuel consumption, but the flammable gas can be challenging to store. KAUST researchers have now calculated that vast amounts of hydrogen could be inexpensively stockpiled in pipes at the bottom of lakes and reservoirs, potentially boosting hydrogen’s role in tackling climate change[1].
Renewable energy sources such as solar and wind are intermittent, so any excess electricity output must be saved to fill gaps in supply. This can be achieved by powering electrolyzers that split water into hydrogen and oxygen. The hydrogen can be kept until it is needed and then fed into fuel cells to regenerate electricity; the only waste product produced is water.
Hydrogen can also be used in a range of industrial processes, offering a key benefit over storing the electricity in batteries. “Hydrogen can decarbonize sectors that electricity and batteries cannot decarbonize, including shipping, aviation, steel making and ammonia production,” says team member Julian Hunt, a research scientist at KAUST.
Relatively small quantities of hydrogen can be kept in pressurized containers, while larger amounts are stored in depleted natural gas reservoirs or underground salt caverns. Yet these sites are not widely available, and this approach can require transporting hydrogen over long distances.
The international team led by KAUST proposes that hydrogen could be stored in lakes and reservoirs close to where the gas is produced and consumed. The gas would be contained in polyethylene pipes filled with gravel to weigh them down. Crucially, the hydrogen would be at the same pressure as the surrounding water, so that as the water gets deeper, the pressure increases and the pipes’ energy storage capacity rises. Pipes at a depth of 200 meters could offer a lifetime storage cost of US$0.17 per kilogram of hydrogen, which Hunt says would be much more economical than using pressurized containers.
As a case study, the team calculated that California’s Oroville Lake, a 210-meter-deep reservoir, could offer a total energy storage capacity of 86 gigawatt-hours — enough to power 8,000 houses for a year.
The team estimates that worldwide there are 1,760 lakes and 3,403 reservoirs deep enough for this kind of system. These bodies of water could collectively store 12 petawatt-hours, amounting to 40% of global annual electricity consumption. More than 80% of that capacity would be found in the five largest lakes, including the Caspian Sea.
To ensure the pipes remained undisturbed, it would be important to monitor the movement of ships on these lakes. “If a large object were dropped from the surface, or a boat sank and hit the pipeline, it could damage the pipes and release hydrogen,” says Yoshihide Wada, who led the team. Still, any leaking hydrogen would simply bubble to the surface and dissipate harmlessly in the atmosphere, the researchers add.
Although there are no immediate plans to build a hydrogen storage system like this, the team is collaborating with KAUST colleague Thomas Finkbeiner to test a similar system in the Red Sea that will use compressed air to store energy.
Reference
- Hunt, J.D., Nascimento, A., Romero, O.J., Zakeri, B., Jurasz, J., Dąbek, P.B., Strzyżewski, T., Đurin, B., Filho, W.L., Freitas, M.A.V. & Wada, Y. Hydrogen storage with gravel and pipes in lakes and reservoirs. Nature Communications 15, 7723 (2024).| article
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