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US company Sage Geosystems has presented field results showing that its Earthstore underground storage system can provide 18 hours or more of storage capacity, in addition to short-duration power. The solution is said to be cost-competitive with lithium-ion batteries and natural gas power plants. Texas-based Sage Geosystems has announced field results from its full-scale commercial pilot project. It has discovered that its EarthStore energy storage system can provide 18 hours or more of storage capacity to efficiently generate 24/7 base load power when combined with solar or wind generation. Data was obtained by pumping and refluxing water from a well to measure power capacity and duration. According to the company, no induced seismicity was measured either during fracturing or during subsequent pumping operations. The pilot plant has demonstrated that it can also supply high-power, short-duration power during peak demand. “Both long- and short-duration storage intervals improve grid reliability with stable power production,” the company reported. “In addition, formation heat expands the fluid at the bottom of the well and improves round-trip efficiency.” Sage has developed underground energy storage technology that can provide short and long duration storage. The system takes advantage of the pressure energy of a fluid while using the geothermal energy of any underground formation where the level of heat necessary to improve its operation exists. The companys goal is lower temperatures (100ºC to 250ºC) at depths of between three and six kilometers. According to Sage, its EarthStore energy storage design is ready to scale and is not geographically limited. Additionally, it can be used in newly drilled wells and existing oil and gas wells. The company has also reported that based on levelized cost of storage (LCOS), EarthStore can deliver power at a lower cost than lithium-ion battery storage and traditional pumped storage hydropower. “It is also competitive with natural gas power plants, making it a cleaner option for providing auxiliary services, black start services and/or redistributing restricted power during periods of peak demand,” says Sage. However, the company did not provide specific figures on LCOS. Other results of the pilot project are the following: It produced 200 kW for over 18 hours (long duration) and 1 MW for 30 minutes (load following), limited only by the small diameter pipes of the rental surface equipment. Electricity generation with Pelton turbines to power on-site equipment. Measured underground system efficiencies of between 88% and 94%, with an estimated round trip efficiency (RTE) of between 70% and 75%. Formation heat expands the downhole fluid and improves RTE. Fluid losses greater than 2% were measured, which decreased to 1% at the end of the five-week period. The ability to generate 2 MW to 3 MW of net production from a single well has been demonstrated. “We have cracked the code on providing the perfect complement to renewable energy, producing reliable alternative baseload in a way that is cost-competitive with lithium-ion batteries and natural gas plants,” said Cindy Taff, CEO from Sage Geosystems. “The opportunities for our energy storage to provide power are significant, from remote mining operations to data centers to solving energy poverty in remote locations. “We can interconnect with power grids or develop islands/microgrids with a cleaner energy solution that is proven and ready to scale.” |
