Climate technology is leaving the demo stage. MIT Technology Review evaluated dozens of companies from around the world, judging their potential impact, scalability, and signs of commercial progress before selecting ten companies to watch in 2026. The list began in 2023 and is largely made up of companies based outside the United States, with China emerging as a hotspot for technological innovation.
The companies span batteries, wind power, energy storage, and nuclear reactors. WeLion is building semi-solid-state batteries for electric vehicles, while Envision Energy is installing wind power and energy storage in China and around the world.
Energy Dome is building long-duration energy storage systems for the grid that rely on compressed carbon dioxide. Canadian company Moment Energy is repurposing EV batteries for grid-scale storage, turning used vehicle hardware into infrastructure for electricity networks.
Form Energy’s battery bet meets the math
Form Energy is building iron-based batteries that can store energy for multiple days. Its system uses a process called “reversible rusting”: “During discharge, oxygen from the air converts the iron metal to rust, releasing electrons. When charging, current converts the rust back into iron metal.”
The chemistry is simple enough to explain and ambitious enough to test the company’s ability to manufacture at scale. Form Energy began producing batteries at its West Virginia factory for a 150 megawatt-hour system serving Minnesota electricity provider Great River Energy, which is set to come online in 2027.
Form Energy has also signed deals with power providers, including a project with Xcel Energy to use 30 gigawatt-hours of batteries to power a Google data center. That project is expected to come online between 2028 and 2031, and the proposed system could become the world’s largest battery project by energy capacity.
The commercial agreements create an awkward gap between ambition and output. Form Energy aims to reach a cost of $20 per kilowatt-hour, but its current production capacity is 2 gigawatt-hours per year—a fraction of the 80 gigawatt-hours promised through commercial agreements.
Space presents another constraint. Form Energy’s batteries require an acre for every two to three megawatts of capacity, so the technology still has to balance low-cost storage against the physical footprint needed to deploy it.
X-energy brings helium back to the reactor conversation
X-energy is developing small modular reactors called Xe-100 that use helium gas as a coolant. The reactor will operate at higher temperatures and lower pressures than traditional reactors, producing super-heated steam or electricity.
Xe-100 will use TRISO fuel, which resists corrosion and melting. The reactor is designed to be intrinsically safe: if temperatures rise, the reaction naturally slows and stops. Each reactor could produce 80 megawatts of electricity—about one-tenth the capacity of most reactors operating today—and up to 12 reactors could be clustered to provide 24/7 power at a lower cost than traditional nuclear power stations.
The approach has an old pedigree. “The first helium-cooled reactor was proposed for the Manhattan Project but was passed over in favor of a simpler and cheaper water-cooled design.” Nuclear history, apparently, is another market where discarded ideas wait for a better sales pitch.
The potential use case extends beyond electricity. Industrial heating accounts for 18 percent of annual global greenhouse-gas emissions, and Xe-100 could supply heat for oil recovery and refining in the fossil fuel industry.
X-energy’s subsidiary holds a fuel fabrication license from the US Nuclear Regulatory Commission, with its first factory due for completion in 2028. An Xe-100 reactor could be operational by the early 2030s in a Texas project operated by Dow.
The company is also working toward a 320 MW cluster of four Xe-100 reactors in Richland, Washington, with Amazon as a collaborator, and a larger 6 GW fleet in the UK’s northeast. Both projects target the 2030s. The list’s real theme is not novelty; it is whether these companies can turn technically credible systems into infrastructure at the scale their contracts and plans already assume.
Based on
- Here’s how our climate team picked 10 promising companies to watch — technologyreview.com
- 10 climate tech companies to watch | MIT Technology Review — technologyreview.com
- 2026 Climate Tech Companies to Watch: Form Energy and its iron batteries | MIT Technology Review — technologyreview.com
- 2026 Climate Tech Companies to Watch: X-energy and its helium-cooled nuclear reactors | MIT Technology Review — technologyreview.com
