Energy

Google's massive battery uses state-shifting CO2 as a storage medium

Google's massive battery uses state-shifting CO2 as a storage medium
An Energy Dome battery facility
An Energy Dome battery facility
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An Energy Dome battery facility
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An Energy Dome battery facility
One of Energy Dome's CO2-powered grid-scale batteries
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One of Energy Dome's CO2-powered grid-scale batteries

Carbon dioxide doesn't normally get a good rap in terms of eco-friendly energy production. But a new partnership forged by Google will see the greenhouse gas used inside a giant battery to manage and stabilize grid energy produced by renewable sources.

Google says that the partnership with Italian energy company Energy Dome will allow it to employ long duration energy storage (LDES) solutions at its clean energy projects around the world. Such storage solutions are necessary because wind and solar can be fickle energy producers, with significant fluctuations in the flow of electrons depending on climatic conditions. Batteries linked to these facilities can be used to store power when the sun is shining or the wind is blowing and then release some of that stored energy when the weather changes.

The problem is that lithium-ion, one of the current gold standards for grid-scale battery storage, can only store energy that can be dispatched about four hours at a time. While that can help in a pinch, it's not ideal for longer wind and solar disruptions.

Enter the Energy Dome. This solution consists of a large, sealed facility in which a big dome holds carbon dioxide gas (CO2). When there is excess energy being produced by turbines and solar power, the CO2 is compressed into a liquid that is stored. When the grid needs more energy, that liquid is converted back into a gas, and that process spins a turbine. Google says it's akin to steam being released from a pressure cooker. After the liquid is converted back to a gas, it is stored in the dome so that the process can be repeated as needed.

Google says the battery system can feed completely clean energy into the grid for up to a full 24 hours, a significant improvement over lithium-ion based solutions.

Energy Dome itself has already proven its chops through a 20-MW-200-MWh commercial plant in Italy.

One of Energy Dome's CO2-powered grid-scale batteries
One of Energy Dome's CO2-powered grid-scale batteries

"LDES, which Energy Dome is leading with its CO2 Battery, has the potential to commercialize much faster than some of the other advanced clean energy technologies in our portfolio," said Google in a statement about the partnership. "This means we can use it in the near term to help the electricity system grow more flexibly and reliably, alongside other tools we’re developing, such as data center demand response."

While Google has only just announced the partnerships and not the specifics of deployment, Energy Dome has said the tech giant has also made an investment into the company itself. The details of that investment have also not been released at this time.

"Google is committed to powering our operations with clean energy, and Energy Dome’s technologically proven and scalable long-duration energy storage solution can help us unlock rapid progress," concludes Maud Texier, director of EMEA Energy at Google. "But this isn’t just about Google. By helping to scale this first-of-a-kind LDES technology, we hope to help communities everywhere gain greater access to reliable, affordable electricity and support grid resilience as we integrate more renewable energy sources."

Sources: Google, Energy Dome

7 comments
7 comments
BarronScout
Seems a dome or balloon, or any other low pressure volume would be idea to catch the "spent" working fluid (CO2 gas). Not entirely unlike a condenser on steam boiler. I know there could be leakage but even a large cavern such as a mine could be used to capture the off gas.
This is seems like it should be part of a larger group of energy capture "devices" to load balance the grid. There is no ideal or perfect idea that works everywhere, but rather a group of solutions that have same result but are tailored to the location in need. IE: load in a mineshaft (raise and lower tonnes of rock, pump acre feet of water, etc.) molten salt heat sink, etc.
TechGazer
What is the overall efficiency? Compressing the CO2 releases heat, so if they're just dumping that, it's wasted energy. Does "proven its chops" mean actual financial profit over the lifespan of the facility? How does it compare financially with batteries?
Aaron MacTurpen
Rumors here in Wyoming are that this is going to be part of the new AI farm being built outside of Cheyenne.
Username
Why not simply use air and forgo the balloon?
Karmudjun
Thanks Franco, this is a great sound bite. The previous coverage by Loz Blain is 3 years old, but more informative. They envisioned a thermal storage component so that the heat of phase change could be saved for reversal - yielding a 75% efficiency - was that accomplished? Most every visual I see are "renderings" of a system but this article has proven facilities; much bigger than the 2.5 MW 4 MWh discussed in 2022. Proven feasiblity, but no costs listed, no information of cost per MWh. What gives? You can search for Energy Dome but the last pricing I find is in Loz's article which anticipated costs of US$50-60 per MWh.
Jinpa
What is the source of the CO2 gas? How much of it leaks from the domes or tanks? Stored at what psi?
geofff
If a battery farm only filled 10% of the dome's volume, wondering about the economics of matching CO2 domes with cheaper, less weather-proofed battery packs, bathed in non-reactive gas, that are v.low maintainance?