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

Hertha Metals has broken ground on its new iron and steel “innovation complex." Photos courtesy Hertha Metals

Shortly after announcing a $133.65 Series A funding round, Conroe-based Hertha Metals broke ground Oct. 8 on a $100 million factory that will produce steel-grade and magnet-grade high-purity iron.

Hertha’s Chalyx plant, located in Conroe, will manufacture a total of about 10,000 metric tons per year of magnet-grade and steel-grade high-purity iron. The factory will use Hertha’s single-step process to generate high-purity iron for rare-earth-magnet and steel manufacturers in the U.S.

Hertha says Chalyx will be the first U.S. commercial plant for production of magnet-grade high-purity iron.

Chalyx is being built next to Hertha’s headquarters and its Pi100 pilot plant, which will remain in operation. Chalyx and Pi100 will form the first modern-day iron and steel “innovation complex” in the U.S., the company says.

“I founded Hertha Metals because I believed we could significantly improve how the world makes iron and steel from ore, and that an industry so fundamental to our future still had enormous room for invention,” Laureen Meroueh, founder and CEO of Hertha, said in a press release.

The 4-year-old startup says the Chalyx complex will lay the foundation for its first 500,000-ton-per-year steel mill.

Chalyx’s first priority is making high-purity iron for U.S. manufacturers of rare-earth magnets, Hertha says. These magnets are critical components for electric vehicles, data centers, wind turbines and defense systems.

China produces an estimated 94 percent of high-purity iron for rare-earth magnets, according to Hertha.

Aside from iron for rare-earth magnets, Chalyx will make iron and steel for pilot projects in the steel industry.

The plant is expected to come online in late 2027, with production of magnet-grade high-purity iron starting in early 2028.

Today, Hertha employs 32 people, the company says. Once it’s fully operating, the Chalyx plant will employ about 50 people.

Just ahead of the groundbreaking, Hertha announced the $133.65 million Series A round, co-led by Khosla Ventures and Doerr Capital. The round included a $65 million equity investment from the Pentagon.

“Iron and steel have shaped human progress for thousands of years. And I believe there is still an enormous amount left to invent,” Meroueh said at the groundbreaking ceremony.

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