top honor

8 Houston energy companies land on Time's top greentech list for 2025

Fervo Energy claimed a top 10 spot on Time magazine and Statista’s new list of America’s Top GreenTech Companies of 2025. Photo via Getty Images.

The accolades keep rolling in for Houston-based Fervo Energy, a producer of geothermal power.

Fervo lands at No. 6 on Time magazine and Statista’s new list of America’s Top GreenTech Companies of 2025. The ranking recognizes sustainability-focused companies based on factors such as impact, financial strength, and innovation.

Time notes that Fervo broke ground in 2023 in Utah on what the company claims will be the world’s largest geothermal plant. The plant is scheduled to start supplying carbon-free electricity to the grid next year and to reach its 400-megawatt capacity in three years.

“Technologies like this only make a difference if we deploy them at large-scale in a way that can reduce carbon emissions and increase the reliability of the grid,” Fervo CEO Tim Latimer told Time in 2023.

The startup was named North American Company of the Year by research and consulting firm Cleantech Group for 2025. Fervo topped the Global Cleantech 100, Cleantech Group’s annual list of the world’s most innovative and promising cleantech companies.

Last year, Fervo also made Time’s list of the 200 Best Inventions of 2024. Fervo was recognized in the green energy category for its FervoFlex geothermal power system.

Founded in 2017, Fervo is now a unicorn, meaning its valuation as a private company exceeds $1 billion. The startup’s valuation is estimated at $1.4 billion. According to PitchBook data, the company raised $634 million in the fourth quarter of 2024.

In all, eight Houston-area companies appear among the top 250 greentech companies ranked by Time and Statista. Other than Fervo, they are:

  • No. 43 Lancium Technologies, an energy storage and distribution company
  • No. 50 Solugen, a producer of sustainable chemicals.
  • No. 56 Quaise Energy, which specializes in terawatt-scale geothermal power.
  • No. 129 Plus Power, a developer, owner and operator of battery storage projects.
  • No. 218 Dream Harvest, which promotes sustainable vertical farming.
  • No. 225 Cemvita, which uses synthetic biology to convert carbon emissions into bio-based chemicals.
  • No. 226 Syzygy Plasmonics, which decarbonizes chemical production.
Vermont-based BETA Technologies claimed the No. 1 spot. The company manufactures electric aircraft.

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A View From HETI

The funding will support the construction of the Hertha Chalyx plant. Photo courtesy Hertha Metals

Conroe-based Hertha Metals has closed a $133.65 million Series A round that includes a $65 million equity investment from the Pentagon. The startup uses a one-step process to convert iron into molten steel or high-purity iron.

Khosla Ventures and Doerr Capital co-led the round, with participation from CEV, Pear Ventures, Gates Frontier, Niterra SUISO no MORI Fund, Toyota Ventures, and Siemens Financial Services.

The federal investment came from the U.S. Department of Defense’s Industrial Base Analysis and Sustainment program. The program aims to strengthen and modernize the U.S. Defense Industrial Base, a network that researches, designs, builds, and maintains military weapons, equipment, technology, and services.

The Series A funding will finance construction of Hertha Chalyx, a plant that will be capable of producing 10,000 metric tons of steel-grade and magnet-grade high-purity iron.

Hertha says Chalyx will provide U.S.-made material for manufacturers of rare-earth magnets. Today, China controls more than 90 percent of the global manufacturing of rare-earth magnets.

Rare-earth magnets can be found in fighter jets, smart bombs, submarines, satellites, drones and other military hardware. These magnets are also key components in electric vehicle motors, wind turbines, computer hard drives, smartphones, headphones, cordless tools and an array of other products.

“Every electric vehicle, aerospace platform, radar system, and data center depends on domestic iron and magnet feedstock suppliers,” Laureen Meroueh, founder and CEO of Hertha, said in a press release.

“Hertha Chalyx closes that gap,” she added. “We are building the supply chain this country needs, and we are doing it by providing a domestic cost-competitive option for manufacturers while unlocking safer and cleaner production.”

Hertha says Chalyx, alongside its Pi100 pilot project, will be the first modern-day “iron and steel innovation complex.” The startup expects to break ground on Chalyx this year.

Since its founding in 2022, Hertha has raised more than $150 million from investors.

This spring, Hertha led the manufacturing category on Fast Company’s list of the World’s Most Innovative Companies of 2026.

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