If Japan were able to turn all excess renewable energy into hydrogen, it could fill the tank of almost 3 million fuel cell vehicles. This is a calculation based on an idealized scenario, of course, but it indicates just how much resource potential is wasted without a way to store energy from variable renewable sources such as solar and wind.

Several pilot projects recent launched in the north and south of Japan seek a way to put the wasted electricity to good use. Using excess renewable power to produce hydrogen is a key decarbonization option for Japan because the process allows using more wind and solar power generation, rather than curtailing output at off-peak times.

Such imbalances in the power grid will only increase as Japan looks to expand the share of renewables to 36-38% by 2030, from about 18% in 2019. What’s more, harnessing excess power to produce hydrogen requires the development of new technologies, which could become a major export opportunity.