The US Department of Energy (DOE) announced the commercialization of a rechargeable energy storage device capable of operating in the extreme temperatures necessary for geothermal energy production. Industry partner FastCAP Systems has successfully completed third-party validation testing by Sandia National Laboratory of an ultracapacitor that is fully operational in 200 °C conditions, extending the upper limit of high-temperature energy storage and electronics, and engineering a flexible system that could reduce cost and risks of geothermal drilling.
During the validation testing, two prototypes were held at constant max voltage at 200˚C+ for more than 500 hours. The cells showed little performance degradation over this timeframe. Similar tests performed in parallel with the Sandia tests in the FastCAP laboratory over longer timeframes have shown the cells to perform failure free for more than 2,500 hours. The stable performance and extreme long life of these cells position the technology for commercial deployment without further development, FastCap said.
It was important to us to showcase a hermetically sealed and commercial ready technology, as opposed to a small piece of a cell tested in a controlled laboratory experiment. These cells are ready to enter the market and will start making an impact in the short term.—Nicolò Brambilla, a Senior Engineer and Team Lead for FastCAP’s Geothermal Technologies Office program
A $2.2-million Energy Department investment, coupled with $5.5 million in private investment funds, yielded this first-of-its-kind product. (Earlier post.) The devices are expected to be released commercially later this year and were developed under a grant from the Department of Energy Geothermal Technologies Office (GTO) in 2012.
Widespread adoption of geothermal energy production is impeded by the cost of drilling deep wells in very hot formations—one of the greatest cost drivers in geothermal development. FastCAP’s innovation targets this challenge: by utilizing a novel combination of downhole energy generation and storage capability, FastCAP’s system can generate and store the necessary power for downhole measurements while drilling (MWD), as well as enable communication with the surface. Combining these advancements will yield a complete geothermal downhole power source.
The final upper operating temperature goal of the project is 250 °C, though FastCAP expects its 200 °C ultracapacitor technology to be deployed downhole as early as this year.
The Geothermal Technologies Office (GTO) funds more than 150 geothermal research, development, demonstration, and analysis projects.
Data from this project and other GTO-funded research will be made publicly available via the National Geothermal Data System (NGDS) on an open-source platform.