Climate tech investment is in a holding pattern — which hasn’t stopped climate entrepreneurs pressing forward with ingenuity, grit and vision.

Early- and growth-stage climate tech investment totaled $13.2 billion in the first half of 2025, down 19 percent from the year prior, according to CTVC. This cooling market is pushing founders back to fundamentals: proving unit economics and delivering superior customer value.

Policy winds have also shifted. The Trump administration has rolled back many, though not all, of the Inflation Reduction Act’s incentives, creating headwinds for renewable energy and electrification.

Still, tailwinds remain for technologies aligned with the AI and data center boom, including nuclear energy, geothermal and energy storage. And carbon capture is finally entering the mainstream, with innovative startups getting both investment and commercial traction.

The next wave

Against this backdrop, Trellis’s annual 25 Climate Tech Startups to Watch showcases the next wave of innovators. This year, 109 startups applied from 13 countries, having collectively raised more than $750 million. From this pool, 25 founders will pitch across breakout sessions at Trellis Impact 25, with the winner — decided by live audience voting — crowned Trellis Startup of the Year at VERGE, Oct. 28–30 in San Jose.

The format is simple: founders pitch their solutions to a panel of investors and corporate leaders, gaining visibility, connections and a spotlight within the Trellis network. And the Trellis community gets a roadmap for where climate tech is heading.

For the first time, Trellis also shared a snapshot of the applicant data. While application numbers have held steady year to year, the capital flowing into applicants has nearly doubled since 2022. The median raise climbed from $766,000 to $2.1 million in that period, showing that more startups are securing meaningful rounds. Sector representation is diversifying, too: energy remains important but less dominant, while industry and nature-focused solutions are gaining momentum and transport continues to lose share. (See the top 25 Climate Tech Startups of 2024.)

Together, these shifts reflect a climate tech ecosystem that is maturing, broadening and showing stronger impact — even amid macro funding slowdowns.

Why these 25 startups stand out

Every startup on the Climate Tech 25 has seed or series-A funding and demonstrates an edge in each of five criteria: solution, business model, customer need and traction, team and pitch presentation. All are incorporated, have already developed a product and employ at least one person full-time.

Trellis’s team of climate experts narrowed 109 submissions down to five of the most promising companies in each of the five categories: land use and carbon; energy; transport; industry; and nature.

Land Use and Carbon

Energy

Notable startups include Fourth Power (multi-day thermal batteries), SkyCool Systems (materials to reduce building heat without energy use), Revterra (balances power fluctuations for renewables), Accelerate Wind (rooftop wind turbines), and Ammobia Inc. (low‑cost clean ammonia).

Transport

Includes Greenlane (EV charging for trucks and heavy vehicles), Celadyne Technologies (clean hydrogen for maritime and heavy duty), Volexion (Li‑ion battery cathode materials), Photon Marine (electric boat motors), and Universal Fuel Technologies (Unifuel) (renewable feedstocks to SAFs and chemicals).

Industry

Includes Sun Metalon (metal waste to reusable material), DexMat (lightweight alternative to metal), Birch Biosciences (molecular recycling for plastics), E-ThermoGentek (thermoelectric modules from waste heat), and Hamilton Perkins Collection (waste plastic to textiles).

Nature

Includes Working Trees (silvopasture carbon with ranchers), Dunya Analytics (nature impact analytics), Airbuild (algae systems for water and carbon), Ecovia-Bio (biobased polymers), and Hempitecture (hemp fiber insulation).

Trellis invites readers to watch founder pitch videos and cast votes on the full list page; the online vote winner is announced at VERGE.

Source

• 25 Climate Tech Startups to Watch in 2025 (Trellis)