Energy storage challenge

(Washington) Six goals

90% reduction in energy storage cost by 2030. It is one of the six goals announced by the US Department of Energy in 2021 for the energy transition. These are “Earthshots”, “Moonshots”, expressive, bordering on the extravagant, referring to ambitious projects.

At the AAAS meeting, Department of Science Undersecretary Geraldine Richmond emphasized this point. “If you include hydrogen, a third of our Earthshots are for renewable energy storage, isn’t that amazing? ” said the chemist from Kansas, with an enthusiasm unusual in a scientist.

About ten long-term storage technologies – ie more than 10 hours – will spend more than half a billion US dollars on energy in the next few years. They range from pumping liquids into elevated tanks to heating solids. Improvements in batteries are also on the menu with an investment of 6 billion US. Hydrogen Earthshot aims to reduce the cost of hydrogen produced from renewable energy by 80% from US$1 per kg.

The case of Alaska

Last spring, M.^me Richmond visited two solar energy projects in Alaska’s coastal villages of Kotzebue and Utgiagvik. Energy is stored in batteries to ensure continuous supply. “When these communities are powered by diesel generators, there is always background noise day and night,” said Ms.^me Richmond. Imagine the change [sans ce bruit] ! We’re not just talking about energy transition, it’s really a question of quality of life. »

Other Earthshots

• Reduce by 85% the emissions related to industrial heating required for the treatment of materials, for example in the production of plastics and metals.
• Reduce CO capture and storage to US$100 per tonne₂ weather
• Reduce the cost of geothermal energy by 90% from US$45 per megawatt hour.
• Reduce the cost of offshore wind energy by 95% to US$45 per megawatt hour.

Ammonia trail

A session on energy storage at the AAAS conference featured two speakers specializing in ammonia, a molecule composed of nitrogen and hydrogen that is gaseous but easily liquefied.

“In my opinion, this is the fuel of the future,” says Bill David of the University of Oxford in England. “I initially worked on batteries, but I kept the storage in gaseous form, because it is the only way to preserve the current infrastructure for energy transport and consumption. »

Mr. David presented the ammonia production reactor he designed. A chemist from Australia’s Monash University, Alexander Simonov, has gone even further: by 2025 he hopes his company, Jupiter Ionics, will be able to commercially produce ammonia and water from solar energy with electrolysis. “In three years, we improved the process tenfold,” says Simonov. Imagine what could be possible in the next few years. »

New fertilizers

Ammonia is currently used to make fertilizers, thanks to a very energy-intensive process invented a century ago by Haber-Basch. “Haber-Basch helped revolutionize agriculture, but its high temperatures and the need to use hydrogen from methane were a big problem,” Simonov said. I believe that in two decades, we will be able to produce fertilizer from renewable energy at a lower cost than Haber-Bosch. It’s slower than using ammonia as fuel, but it gets there. »

When can we replace Haber-Bosch with “green” ammonia? “We can think that by 2030, we will be able to introduce small green ammonia production units to areas poorly served by transport, for example in Africa”, says the chemist of Russian origin.

Example of Singapore

Mr. Simonov offers proof of green ammonia’s golden future: A company in Singapore has begun work on the first ammonia-powered container ship. The Port of Singapore last summer signed a design agreement with Hyundai Shipyards for a line of ammonia-fueled vessels.

Vopak, a Singapore-based multinational industrial gas and liquids storage company, anticipated this transition and began building ammonia tanks in an Asian port. “Ammonia is a better fuel than hydrogen because it is liquid at 10 times less pressure,” Simonov said. It liquefies even at -30°C, but for hydrogen, it is close to absolute zero [NDLR : -273 °C]. So we can design safe tanks for cars, for example. » Ammonia derivatives are important car pollutants? “Yes, but there are catalysts to remove them from the exhaust,” says Simonov.