U.S. Climate Tech Seed Funding: Q1 2026 Review

U.S. climate tech startups raised $206M across 23 Seed funding events in the first quarter of 2026. 19 of these were milestone Seed rounds and 4 were extensions, second closes, etc.

Key takeaways:

    • Seed dollars rose while the round count fell. Companies raised $206M, up from $172M the prior quarter and $183M a year ago. Milestone rounds (excludes extensions, bridges, pre-Series A, etc) dropped to 19, from 21 in Q4 2025 and 23 in Q1 2025.

    • Energy took most of the money. Energy companies accounted for $117M, about 57% of Seed dollars and 11 of the 19 milestone rounds. Transportation, Industry, and Built Environment split the rest.

    • Two $30M rounds sat at the top. Claros and Voltify each raised $30M, more than four times the quarter’s $6.5M median.

The headline numbers

Metric Q1 2026
Total Seed raised $206M
Milestone rounds 19
Average milestone round size $8.7M
Median milestone round size $6.5M

How Q1 compares

Quarter over quarter (vs Q4 2025): Seed dollars rose about 20%, from $172M to $206M, while milestone rounds fell from 21 to 19. The average round grew from $7.3M to $8.7M, and the median from $6.0M to $6.5M.

Year over year (vs Q1 2025): dollars rose about 12%, from $183M, and milestone rounds fell from 23 to 19. The average a year ago was $7.7M.

Both comparisons point the same way. More capital went into Seed this quarter, spread across fewer companies, which lifted both the average and the median round size.

Where the money went

Energy led by a wide margin, with the other dollars split across three verticals. Three of our seven verticals saw no U.S. Seed activity this quarter: Carbon, Climate Management, and Food & Land Use.

Vertical Seed $ Share Milestone rounds
Energy $117.4M 57% 11
Transportation $33.4M 16% 2
Industry $28.5M 14% 3
Built Environment $26.5M 13% 3

By technology type, physical plays took 69% of Seed dollars ($143M), digital took 28% ($57M), and bio took 3% ($6.0M, a single round).

Deals that stood out

Two rounds led the quarter. Claros raised $30M, co-led by General Catalyst and Red Cell Partners, for efficient power-management systems that sit between the chip and the grid in data centers. Voltify also raised $30M, co-led by Aleph and Fortescue, to build battery-electric locomotives and rail infrastructure. 

Data center power ran through several of the quarter’s larger rounds. Beyond Claros, Emerald AI raised a $25M Seed 2 (we count that in the dollar total but not the milestone count) for software that turns AI data centers into flexible grid loads. Energy Impact Partners led, with Nvidia’s NVentures, GE Vernova, Eaton, and Siemens among the backers.

Nuclear appeared twice. Project Omega came out of stealth with $12M for spent-fuel recycling and radioisotope batteries, and Applied Atomics raised $8.3M for medium-modular nuclear plants.

Only one Seed round was a biotech play: Transition Metal Solutions raised $6M for biomining additives that recover copper, led by Transition.

The full Q1 2026 Seed list

All 23 U.S. climate tech Seed events from Q1 2026, ordered by round size. Company names link to the company, each amount links to the round’s source, and lead investors link to their sites.

    • Voltify $30M
        • Battery-powered locomotives and rail infrastructure

        • Other investors: Chemi Peres, Menomadin Foundation, J-Impact Fund, theDOCK, Yasmin Lukatz

    • Emerald AI $25M*
        • AI data center demand-flexibility software

        • Other investors: Amplo, Eaton Corporation plc, GE Vernova, IQT, Lowercarbon Capital, NVentures, Radical Ventures, Salesforce Ventures, Samsung Ventures, Siemens

    • Project Omega $12M
        • Nuclear fuel recycling and radioisotope batteries

        • Other investors: Mantis Ventures, Buckley Ventures, Decisive Point, Slow Ventures

    • Helix Earth Technologies $12M*
        • Pre-dehumidification retrofits for commercial HVAC

        • Other investors: Carnrite Ventures, Rua Growth Fund, Skywriter, Textbook Ventures

    • Ammobia $7.5M*
        • Modular low-pressure ammonia synthesis

        • Lead investors: undisclosed

        • Other investors: Shell Ventures, ALIAD (Air Liquide), MOL Switch, Chevron Technology Ventures, Chiyoda Corporation, Katapult Ocean, AIR Capital, Alumni Ventures, Motivate Fund, Starlight Ventures, The Collaborative Fund, Arosa Capital, Zero Infinity Partners

    • Coral $7.5M
        • Rebate-advance platform for HVAC contractors

        • Other investors: Twelve Below, Floating Point, Accion Ventures, Blackhorn Ventures, Remarkable Ventures, New Climate Ventures, Watsco Ventures

    • Powerline $7M
        • Grid-scale battery portfolio optimization

        • Other investors: LG Technology Ventures, J-Impact Fund, Alumni Ventures, CLAI

    • Derapi $7M
        • Universal API for distributed energy resources

        • Other investors: Tuesday Capital, Susquehanna Sustainable Investments, WYVC, Breakthrough Venture Capital, WovenEarth Ventures LLC, Radicle Impact, Raisewell Ventures, GreenSky Capital, Aurora Venture Investments

    • Transition Metal Solutions $6M
        • Biomining additives for copper recovery

        • Other investors: Dolby Family Ventures, Astor Management AG, Juniper, Understorey Ventures, New Climate Ventures, Essential Capital, Kayak Ventures, Climate Capital, Possible Ventures, SOSV

    • CVector $5M
        • Industrial AI plant-economics platform

        • Other investors: Fusion Fund, Hitachi Ventures, Myriad Venture Partners, Schematic Ventures

    • DexMat $5M*
        • Conductive carbon-nanotube material

        • Other investors: Governance Partners, Tailwind Futures, BetterWay, Capital Factory

    • Qnetic $5M
        • Long-duration grid-scale flywheel energy storage systems

        • Lead investors: undisclosed

        • Other investors: Kingscrowd Capital, D3 Venture Capital, SOSV

    • PolyGone Systems $4M
        • Microplastic filtration systems for water

        • Other investors: Tech Council Ventures, Interstate Fusion Ventures, Golden Seeds, New Jersey Economic Development Authority

    • Arinna $4M
        • Ultra-thin flexible space solar cells

        • Other investors: Anorak Ventures, Breakthrough Energy Foundation

    • Emobi $3.4M
        • EV charging interoperability platform

        • Other investors: Aves Ventures, The Collaborative Fund, Gaingels, gener8tor, Goodwater Capital, Oasis Capital, OneSixOne Ventures, Ride Wave Ventures, Y Combinator

* Interim rounds (e.g. an extension, second close, pre-Series A, etc). Our dollar totals include these; the round count does not.

Methodology

    • Universe: U.S.-headquartered climate tech companies that announced a Seed round dated in Q1 2026 (January through March).

    • Counting convention: dollar totals include extensions and second closes; round counts include milestone (primary) rounds only.

    • Averages are computed within a single stage for rounds with disclosed amounts.

    • Source: Planetary Scale climate funding database, built from public announcements and disclosures.

Planetary Scale is a fractional CFO and strategic finance firm for venture-backed climate tech startups. Learn more at www.planetaryscale.co

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