Three energy storage projects have reached key milestones, including pumped hydro, thermal storage, and geothermal technologies that complement the roles of battery energy storage systems (BESS).
The Federal Energy Regulatory Commission issued a 40-year license for the 1,200MW Goldendale pumped hydro energy storage (PHES) project in Washington State, developed by Rye Development and Copenhagen Infrastructure Partners.
In Texas, Electrified Thermal Solutions commissioned its first commercial-scale thermal battery at Southwest Research Institute.
Meanwhile, geothermal company Sage Geosystems closed US$97 million in Series B funding led by Ormat Technologies and Carbon Direct Capital.
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These projects cater to various market needs. Goldendale focuses on grid-scale storage in the Pacific Northwest, where electricity demand is expected to increase by over 30% in the next ten years. The thermal battery is designed for industrial heat applications, which account for about 20% of global energy consumption. Meanwhile, Sage’s geothermal technology intends to support the energy needs of AI data centres with long-duration energy storage (LDES).
FERC issues 40-year license to Rye Development, CIP for pumped storage project
The Federal Energy Regulatory Commission (FERC) has issued a 40-year license to ‘low-impact pumped hydro storage’ developer Rye Development and fund management company Copenhagen Infrastructure Partners’ (CIP’s) ‘Goldendale’ pumped hydroelectric ‘Energy Storage Project’, in Washington, US.
The license for the 1,200MW project was granted on behalf of CIP’s flagship fund CI V. Goldendale will be located on private lands at the site of a former aluminium smelter near Goldendale, Washington.
Rye Development claims Goldendale represents a major investment, anticipated to generate over 3,000 family-wage jobs during its four to five-year construction phase, along with numerous permanent positions. Upon completion, it is projected to provide more than US$10 million each year to Klickitat County, helping fund schools, public health, roads, emergency services, and other community needs.
In 2020, CIP acquired Goldendale and the 400MW Swan Lake pumped hydro project in Klamath County, Oregon, from Rye Development and National Grid, which was previously developing them through a joint venture (JV).
At the time, Rye Development said it would continue to lead the two closed-loop pumped hydro projects until the beginning of construction.
The memorandum of understanding (MOU) to build the project outlines that all Goldendale contractors must employ union workers through a labor agreement with the Washington State Building & Construction Trades Council and the Columbia Pacific Building & Construction Trades Council.
The MOU emphasises prioritising local hires. With a construction period spanning four to five years, apprentices will have the chance to acquire a trade and earn a “competitive wage.”
Rye Development cites the August 2024-July 2034 Northwest Regional Forecast of Power Loads and Resources report from the Pacific Northwest Utilities Conference Committee (PNUCC), stating that electricity demand in the Northwestern US is expected to grow by more than 30% over the next decade, along with rising electricity prices for residential and commercial customers.
The company states that pumped storage hydropower contributes to lower electricity costs by offering large-scale, reliable energy storage, even in extreme weather conditions.
Although lithium-ion batteries currently lead the global market for new energy storage systems (ESS), most existing storage capacity is still based on pumped hydro.
The technology provides a low marginal cost of storage after construction by using two large water reservoirs, one at a higher elevation and one at a lower, allowing water to flow from the upper to the lower reservoir through turbines to generate electricity. After passing through the turbines, the system can be replenished using solar or wind power to pump the water back up for reuse.
Electrified Thermal Solutions commissions commercial-scale thermal battery
Thermal energy storage (TES) developer Electrified Thermal Solutions (ETS) has commissioned its first commercial-scale Joule-Hive Thermal Battery at Southwest Research Institute (SwRI) in San Antonio, Texas.
The system draws AC electricity from the grid and stores 20MWh of heat at peak temperatures of 1,800°C (3,275°F). This heat is delivered on-demand as hot gas to industrial furnaces, boilers, and kilns, with temperatures adjustable up to 1,500°C.
The hot gas supply can be raised to a delivery temperature of 1,800°C, suitable for use in industries like steel, cement, chemicals, and glassmaking.
According to ETS, this initial unit draws directly from 13.2kV AC power, allowing a straightforward configuration that matches the standard line voltage used in industrial campuses.
The company claims this design significantly reduces balance of plant (BOP) costs compared to other electric heating systems that require step-down transformers. The modular system, suited for commercial use, can serve thermal loads of 1-5MW, with additional modules available to scale and meet individual customer needs.
ETS touts another advantage of its technology, saying that industrial heat consumes about 20% of global energy, with 89% of that from fossil fuels. Many areas in the US and Europe experience negative electricity prices, especially during off-peak hours. Electrified Thermal’s Joule Hive thermal battery enables industries to use “inexpensive, clean electricity” from the grid, competing with fossil fuels on price and enhancing grid flexibility.
Industrial heat has traditionally been challenging to decarbonise because it requires high-temperature, high-quality heat. Unlike batteries, which can directly replace power generation easily, electrifying heat has been more complex.
According to the company, Joule Hive significantly reduces capital and operating expenses by using proprietary electrically conductive firebricks that last over 20 years and by storing energy during periods of low electricity rates. Electrified Thermal has also obtained letters of intent from clients in various industries and plans to deploy 2GW of thermal power capacity by 2030.
In October 2025, technology provider Rondo Energy began commercial operation of what is claimed to be the world’s largest industrial thermal energy storage ‘heat battery’, its 100MWh Rondo Heat Battery (RHB) system at an industrial facility in California operated by Holmes Western Oil Corporation.
The RHB is charged directly by an on-site solar PV array. Rondo states it has a round-trip efficiency (RTE) exceeding 97%, stores heat at temperatures above 1000°C, and provides 24-hour continuous heat.
With the SwRI system now operational, Electrified Thermal says it is positioned to begin commercial deployments with industrial partners this year.
Sage Geosystems raises US$97 million for geothermal power plant
Geothermal company Sage Geosystems has closed over US$97 million in Series B funding to advance its first commercial geothermal power generation facility.
US geothermal renewable energy and battery storage company Ormat Technologies and investment firm Carbon Direct Capital co-led the funding round.
Sage says its geothermal long-duration energy storage (LDES) solutions will support the build-out of AI data centres.
The company plans to deploy its first commercial Pressure Geothermal power plant at an Ormat facility. It will utilise Sage’s proprietary technology to extract geothermal heat energy from hot dry rock.
Sage says its strategic commercial agreement with Ormat will accelerate the time needed to bring Pressure Geothermal to market and scale up to meet rising demand for “firm power and energy independence.”
Pressure Geothermal develops a fully engineered underground hot water reservoir that expands and contracts with the earth’s natural movements. By utilising hot, dry rock formations across the globe, Sage says it unlocks over 130 times more geothermal potential in the US alone.
According to Sage, its EarthStore solution harnesses mechanical energy from the earth within a single well to charge and discharge energy, supporting LDES applications ranging from over 8 hours to several days.
In August 2024, the company announced a partnership with Meta to provide up to 150MW of new geothermal baseload power at a site east of the Rocky Mountains in the US, supporting Meta’s data centre expansion.
In 2020, Ormat diversified from geothermal energy, opening its energy storage division and targeting rapid growth.
In 2025, the company began commercial operations at its 60MW/120MWh Lower Rio energy storage facility in Texas.
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