Climate change is real, and so are its effects. The political power corridors of the world realized that in the race to cover our energy consumption, we are creating threats to the world’s future by relying on Fossil Fuels. In the meantime, renewable energy sources have the problem of intermittency, as even when these are abundantly available, they are not consistent. So, we require a lot of energy storage capacity, and researchers recently stepped into making a CO2 battery.
Every day we find a new power storage method with the hope of discovering long-duration energy storage that supports renewable grid integration to much higher levels. The usual lithium-ion batteries are perfect for a limited and small storage system, such as EVs and off-grid systems, but these are not enough to cover a storage system for renewable power integration up to 70% as planned to achieve in many countries by the end of next decade.
So, engineers are looking for a cost-effective method with almost unlimited charging cycles and a very efficient system. Among many recent research and tests for high quantity power storage systems, gravity storage, air liquefication storage, sand batteries, and hydro pump storage are a few, with CO2 battery as the latest competitor.
What is a CO2 battery and how do they charge it?
Energy dome is a Milan-based startup that introduced the C02 battery, a giant closed-loop thermodynamic system. It consists of a dome-shaped storage tank holding CO2 at atmospheric temperature and pressure. CO2 battery utilizes the surplus energy from renewable energy power plants to drive the motor that draws CO2 from the storage tank.
CO2 gas gets pressurized through a turbo compressor turning CO2 into a highly dense liquid. That CO2 liquid gets stored in a fire extinguisher kind of tank at a very high pressure of 70 bar but at room temperature. The whole system recovers and stores the compression-induced heat into two thermal units, and that completes the charging cycle.
CO2 battery discharging process
The discharging process is much simpler and utilizes the same recovered heat to convert CO2 liquid into vapors. CO2 passes through an expander, where a high-pressure stream drives the turbine to generate electricity that gets delivered back to the grid, and CO2 gets back to the storage tank. The whole CO2 battery system is a close loop, which has negligible losses in the process. Energy dome’s CEO claims that once loaded, CO2 is enough to run the CO2 battery for 30 years.
Advantages of CO2 batteries
- Energy dome claims that liquified CO2 has 11 times more energy density than compressed air energy (CAES).
- Liquid air energy storage (LAES) is two times denser than liquified CO2 but has an efficiency of 45 – 75%, whereas liquified CO2 has an energy efficiency of 75 – 80%.
- CO2 battery would be 50% upfront cheaper than the lithium-ion battery for the same storage size for a long-duration storage system.
- Considering the Levelized cost of storage (LCOS) of a 25MW/200MWh plant CO2 battery will cost $50/MWh, whereas lithium batteries cost $132 – $232/MWh, liquid air energy storage (LAES) costs $300/MWh, and Hydro pumped storage cost $186/MWh making it the cheapest storage option.
Conclusion
Carbon dioxide (CO2) gets portrayed as a convicted criminal for climate change, and maybe this is the time where it gets a chance to show its other side by playing a role in renewable energy grid integration at a higher level by reducing the need for fossil fuels to generate power, thanks to the Italian startup Energy Dome.
YouTube: Energy Dome – This new battery uses CO₂ to store wind and solar power
Photo credit: The feature image is owned by Energy Dome and was provided as part of a press release.
