A Giant Energy Dome Is Daringly Turning Carbon Dioxide Into Power

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One of the major engineering challenges facing the green energy revolution is the need for cost-effective methods of storing energy.
Energy Dome, an Italian startup, is turning to CO2, the leading culprit of the climate crisis, to try to solve this lasting conundrum by compressing the greenhouse gas into a liquid for storage and eventually using that gas to power turbines when the sun isn’t shining, and/or the wind isn’t blowing.
While this has some big advantages over similar techniques, particularly because CO2 can stay liquid at ambient temperature (under high pressure) and is more energy-dense than air, the technology could eventually become outclassed by the rapidly improving battery technology.

One of the big stumbling blocks between today and our green energy future is energy storage. After all, sometimes the wind doesn’t blow and the sun doesn’t shine, so designing ways to effectively store energy is an extra-critical component of combating climate change. That’s why engineers have designed new types of batteries, whether powered by lithium rust, or even gravity, to figure out ways to tackle this relentlessly difficult engineering problem.

Now, the Italian startup Energy Dome is ready to debut its counterintuitive take on energy storage by combating decarbonization with … more carbon?

For years, the company has been perfecting the chemical technologies needed to create a carbon dioxide-powered battery. Because CO2 liquifies at ambient temperatures under pressure and has higher energy density than air, the approach has some clear advantages over similar techniques such as liquid-air energy storage and compressed-air energy storage.

As the company’s name alludes to, 100o tonnes of CO2 gas is first stored in a giant dome. While solar panels and wind turbines are pumping out electrons, Energy Dome pumps the gas into a compressor where it’s heated, compressed into a liquid, and stored in carbon steel tanks. Then, when energy is inevitably needed during those sunless and/or windless moments, an evaporator turns the liquid into pressurized gas, and once reheated, the released CO2 powers turbines and generates electricity.

According to a 2022 interview with MIT Technology Review, Spadacini says a full-scale plant should cost $200 per kilowatt-hour (kWh), whereas lithium-ion battery tech costs $300 per kWh at the time. New Scientist reports that such a plant will store power for 8 to 24 hours.

“What we provide is a technology which is intended to be in the daily storage market. It means to switch energy from day to night, from today to tomorrow,” Spadacini told New Scientist. “That is the main need you have with a wind and solar-dominated grid.”

So could the object of our greenhouse gas derision somehow provide the silver bullet necessary to slay this energy storage lycanthrope? The idea certainly has some big backers, as Energy Dome receives funds through Bill Gates’ climate investment initiative, Breakthrough Energy Catalyst, as well as the European Investment Bank.

And now, after years of talking the talk, Energy Dome is putting its CO2-powered battery plan to work with the first operating commercial plant due to open in Sardinia, Italy, sometime later this year. And the good news doesn’t stop there; Spadacini also says that “a very large, well-known global utility” is interested in the technology.

Of course, downsides exist. For one, a giant, big ol’ bag of still-air CO2 could be a problem if somehow ruptured, and these plants aren’t exactly small; New Scientist writes that a CO2 battery plant could take up anywhere from 12 to 25 acres, or roughly a 3- to 4-megawatt solar farm.

The other problem? Lithium-ion batteries, as well as other next-gen battery technologies, are getting better and better, are already mass produced, and are relatively modular, meaning they’re a bit more plug-and-play than a massive CO2 battery plant.

But the need for cost-effective energy storage has never been greater and will only increase as renewable energy supplants the fossil fuels that got us into this mess in the first place. If CO2 can do good rather than harm, then let’s put it to work.

Darren Orf

Contributing Editor

Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.