The US VCs making the biggest bets on European climate tech

US investors continue to play a significant role in Europe’s impact tech landscape.

Across the 13 most active American funds, they’ve collectively backed 559 European impact startups to date, with 149 of those investments made this year alone, according to Dealroom data.

One of those VCs is Lowercarbon Capital, founded by Chris and Crystal Sacca. The fund has backed 28 European climate tech startups since it launched in 2020.

“Europe just has an incredible amount of talent,” Chris Sacca said during an interview at Slush 2025. “And I really feel like they get this problem. They understand the climate imperative. In the US, we’re still stuck in culture wars.”

Despite the talent, countless founders and investors in recent years – many of them European – have criticised the continent’s cautious regulatory frameworks and risk-averse culture. But Sacca thinks the situation has improved.

“Europe was missing an entrepreneurial culture 20 years ago… you weren’t rewarded for taking risk,” he said. “But that’s changing. Regulators have been giving more room, and they’re now truly engaging with startup founders.”

On average, each of the 13 VCs in this list has supported roughly 43 European companies overall, and about 11 to 12 so far this year, underscoring a steady – and in some cases accelerating – flow of US capital into the continent’s climate and impact ecosystem.

Here's the full list in order of number of investments made:

1. Plug and Play

Founded in 2006 by the ‘Matchmaker of Silicon Valley’ Saeed Amidi, Plug and Play is an early-stage investor and accelerator that has backed 274 impact startups in Europe to date – 66 this year alone. They include Italy’s Energy Dome (long-duration CO2-based energy storage), Dutch startup Sympower (flexibility services for the electricity grid), Latvia-based Aerones (robotic wind turbine maintenance), and Germany’s Bioweg (biotech alternatives to microplastics).

2. Techstars

One of the world’s largest pre-seed accelerators, Techstars has backed 108 European startups, 21 this year, including US/Luxembourg-headquartered startup Hydrosat (thermal infrared satellite analytics), French carbon credit issuer Rainbow, and London-based Cariqa (EV charging marketplace platform).

3. SOSV

Founded in 1995 by web entrepreneur Sean O’Sullivan, SOSV is a deep tech-focused early-stage investor, also known for hands-on accelerator programs.

The fund has backed 37 European startups, 6 this year, including Swiss PFAS-fighting outfit Oxyle, UK’s CroBio (microbial crop enhancement), and London-based Scindo, which uses enzymes to break down tough plastics for recycling.

4. Big Idea Ventures

Early-stage fund focused on foodtech and alternative proteins. It’s backed by Tyson Foods, Temasek, and major food corporations.

Made 30 investments in Europe, 9 this year, including France’s Nutropy (animal-free dairy ingredients) and Italy’s Yeastime (AI-driven fermentation optimisation).

5. Lowercarbon Capital

Chris Sacca’s climate-focused venture fund investing from pre-seed through growth.

Lowercarbon has made 28 European investments – 12 this year. Those include UK startup Seabound (carbon capture for ships), France’s Genomines (metal extraction using plants), Stockholm-based Normative.io (carbon accounting software), and British energy supplier Fuse Energy.

6. Energy Impact Partners (EIP)

EIP is a strategic energy-focused fund backed by more than 70 major utilities and energy corporations. It invests from early to the growth stage. 

EIP has made 15 European investments, 4 this year, including London-based ev.energy (smart EV charging software), UK’s AssetCool (thermal tech for power-line efficiency), Reversion (battery recycling), and Swiss clean jet fuel startup Metafuels, whose CEO Saurabh Kapoor we interviewed earlier this year.

7. Breakthrough Energy Ventures (BEV)

BEV is a climate tech fund founded by Bill Gates, and backed by the likes of Jeff Bezos, Richard Branson, and Michael Bloomberg.

14 European investments, 5 this year, including Germany’s INERATEC (e-fuel production), France’s Mantle8 (advanced hydrogen materials), and Spain’s H2Site (membrane-based hydrogen separation).

8. Acequia Capital

Acequia Capital, founded by early Twitter employee Aydin Senkut, is best known for backing emerging deep tech founders.

The fund has made 12 European impact investments, 5 this year, including Oxford University-spinout Milvus Advanced (composite materials), Germany’s Hyperdrives (next-gen battery tech), and Paris-based Arago (sustainable materials).

9. Lightspeed Venture Partners

Lightspeed is an multi-stage Silicon Valley VC backing both software and deep tech, known for early bets on Snap, Guardant, and Blockchain.com.

The fund has made 9 European investments, 4 this year, including Munich-based Proxima Fusion (tokamak-based fusion) and UK’s CuspAI (AI-designed materials).

10. S2G Ventures

Backed by billionaire heir Lukas Walton, S2G primarily invests in Food, agriculture, and energy systems. The fund has made 9 investments in Europe, 5 this year, including Irish unicorn TechMet (critical minerals refining) and Latvia Aerones (robotic turbine maintenance).

11. At One Ventures

Climate tech fund founded by former Google X VC Tom Chi. At One has made 8 European investments, 4 this year, including French nuclear energy startup Stellaria, UK’s Material Evolution (low-carbon concrete), and Transmutex, another nuclear energy company – this time from Switzerland.

12. Union Square Ventures (USV)

USV is an early-stage investor known for backing Twitter, Etsy, and Coinbase – but it has an expanding climate fund. The fund has made 8 European investments, 5 this year, including Berlin-based Ostrom (digital energy retailer), UK’s Volteras (EV charging data platform), Ireland’s XFuel (low-carbon synthetic fuels).

13. Blue Bear Capital

Blue Bear invests from Series A and beyond, mainly making bets on energy, automation, and industrial AI. The fund has made 7 European investments, 3 this year, including Germany’s Energy Robotics (autonomous inspection robots) and US/Luxembourg-headquartered Hydrosat (thermal satellite analytics).

Pictured top: Crystal English Sacca (Lowercarbon Capital); Laurie Menoud (At One Ventures); Alisha Fredriksson (Seabound); Simon Bushnell (Sympower); Tamara Ciullo (Cariqa); Fajer Mushtaq (Oxyle); Saurabh Kapoor (Metafuels); Rodi Guidero (BEV); Sanjeev Krishnan (S2G Ventures); Hans Kobler (Energy Impact Partners)