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Houston clean energy storage facility goes online to power ERCOT grid

Jupiter Power's Callisto I is up and running. Photo courtesy of jupiterpower.io

A new battery energy storage facility in Houston is officially up and running to power the ERCOT grid with a supply of reliable, zero emissions power.

Jupiter Power announced the commercial operations launch of its 400-megawatt-hour battery facility, Callisto I, in central Houston on the site of the former HL&P H.O. Clarke fossil fuel power plant.

"Jupiter couldn't be prouder about bringing the Callisto I project online," Andy Bowman, CEO of Jupiter Power, says in a news release. "This project responds to lawmakers' calls to increase affordable and dispatchable new generation in an area where people need more power. Callisto I is the first energy storage project at this scale in the City of Houston and will help meet Houston's growing power needs while also increasing resiliency from extreme weather events."

The new project is Jupiter Power's ninth project to deliver energy storage to ERCOT — bringing its total ERCOT fleet to 1,375-megawatt-hour capacity — but its the first in the Houston area. The company is currently developing over 11,000 megawatts of projects across the country. Founded in 2017, Jupiter Power is headquartered in Austin and has offices in Houston and Chicago.

"The announcement of Jupiter Power's Callisto I Energy Storage project is significant and exciting for the region, as it's the first large-scale transmission-connected energy storage project in the City of Houston," Jane Stricker, senior vice president at the Greater Houston Partnership and executive director at the Houston Energy Transition Initiative, adds. "This critical project will help address peak power demand and is another great example of our region's leadership in scaling and deploying impactful solutions for an all the above energy future."

Among the company's financial backers is Houston-based EnCap Energy Transition, which invested in Jupiter Power via its Fund II.

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A View From HETI

Sage Geosystems has selected a site for its next major geothermal facility. Photo via sagegeosystems.com

Sage Geosystems, a Houston-based developer of geothermal power systems, has chosen a site in Nevada for its commercial-scale Project Vector facility.

The company’s two-well enhanced geothermal system (EGS) will deliver around-the-clock geothermal heat to Ormat Technologies’ Blue Mountain geothermal power plant in Winnemucca, Nevada.

The startup expects to begin drilling the first well later this year, with the first electricity to be generated in 2027 and full-scale production to start in 2028.

In the Nevada system, fluid will circulate through an engineered subsurface reservoir, absorb heat from the surrounding rock and return heat to the surface. The heat will be delivered to the Blue Mountain plant for conversion into electricity.

Project Vector builds on the performance of Sage’s SMECI facility in South Texas. That facility’s results, combined with Sage’s digital twin platform, will be used to shape to the design and development of Project Vector.

Project Vector supports Sage’s growing commercial pipeline, including a 150-megawatt geothermal power agreement with Meta Platforms, the parent company of Facebook and Instagram.

“Blue Mountain is an ideal location for Sage to take the next step in continuing to commercialize our proprietary EGS approach,” Jason Peart, chief operating officer at Sage, said in a release. “By delivering geothermal heat into an existing power plant, Project Vector can demonstrate the model for bringing firm, 24/7 geothermal power to market at scale.”

Project Vector extends Sage’s relationship with Ormat.

In August 2025, Sage and Ormat agreed to accelerate commercialization of Sage’s geothermal technology at an Ormat power plant. This January, Ormat co-led Sage’s $97 million Series B funding round.

Sage, founded in 2020, has raised about $159 million across three funding rounds.

As the startup ramps up its ESG platform, Sage is targeting data centers as customers, among other large-scale users of electricity.

“The energy needs are huge, and they need it now,” CEO Cindy Taff said on Data Center Frontiers’ podcast. “They can’t depend on the grid anymore.”

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