Sage Geosystems, a geothermal baseload and energy storage company, recently announced the results and data from its full-scale commercial pilot confirming the performance of its energy storage system that can provide short- or long-duration storage. The company notes that the results show Sage’s technology is cost-competitive with lithium-ion batteries, pumped storage hydropower, and natural gas peaker plants.

The field results from 2022/2023 and extensive data analysis performed in 2023 confirmed Sage can provide 18 hours or more of storage capacity to effectively generate base load energy 24/7 when paired with solar or wind generation, according to the press release. The company notes that the field results also demonstrated that Sage can alternatively provide high-powered, short-duration power (load-following) during peak demand. Both storage intervals, long- and short-duration, enhance grid reliability with stable power output. In addition, the heat from the formation expands the fluid downhole and improves round trip efficiency (RTE), the company said.

The Sage data sets, according to the company, were obtained by pumping in and flowing back water from their well to gauge capacity and power duration. No induced seismicity was measured either during fracturing or subsequent pumping operations.

EarthStore is Sage’s mechanical energy storage technology that harvests the pressure energy of the fluid and is also enhanced by the heat from the formation.

• Produced 200kW for over 18 hours (long-duration) and 1MW for 30 minutes (load-following), limited only by the small diameter rental surface equipment piping.
• Generated electricity with Pelton turbines to power equipment on location.
• Measured subsurface system efficiencies between 88-94%, with an estimated round-trip efficiency (RTE) of 70-75%.
• The heat from the formation expands the downhole fluid and improves RTE.
• Measured fluid losses < 2%, decreasing to 1% by the end of the 5-week period.
• Demonstrated the ability in a single well to generate 2-3MW net output.
• Calculated LCOS that is cost-competitive to pumped storage hydropower and lithium-ion batteries.