Carbon13
Carbon13 is a Cambridge and Berlin climate-tech venture builder that co-founds startups and writes their first pre-seed cheques. It backs carbon-cutting founders across energy, food and materials, with water a thin thread in a carbon-first book. As of June 2026 it has backed 2 water companies across 2 deals and launched its tenth fund.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
Carbon13 calls itself the venture builder for the climate emergency, and the word builder is the point: instead of waiting for founders to arrive with a deck, it assembles them. Carbon13 runs eight-month cohorts in Cambridge and Berlin that pair commercial and technical co-founders, helps them spin up a company around a carbon-cutting idea, then writes the first cheque. As of June 2026 it had backed 107 startups since 2021 and launched its tenth fund, Carbon13 SEIS Fund X.
Carbon13 grew out of Cambridge's climate and university scene on the conviction that most of the world's emissions cuts will come from new companies, not old ones. The money flows through SEIS funds, the UK's Seed Enterprise Investment Scheme that hands investors tax relief for backing very young startups, which is why the cheques are small and very early: (don't) Waste Water records pre-seed tickets around the $140K to $150K mark on the water deals it tracks.
Carbon13 is carbon-first, so water turns up sideways, as a by-product of chasing greenhouse gases rather than a thesis of its own. The clearest example I track is Bluemethane, a Carbon13 venture that strips methane dissolved in wastewater, reservoirs and farm lagoons before it escapes, borrowing the trick of a freshly opened bottle of sparkling water to coax the gas out. It is a water technology in everything but label, born from a carbon mission.
Carbon13 is the case study in how water reaches a generalist climate investor: not through a water fund, but through the founders it builds to chase methane and clean energy who happen to land in the water. The open question is whether water ever graduates from a footnote to a named focus as Fund X deploys, or stays the quiet thread it has been since the first cohort.
Water Commitment Score
Compiled from official filings, third-party records, and direct intelligence from investors and founders, in Leviathan · recomputed monthly · as of Jun 2026.
How they invest
Portfolio · 2 water companies
Frequently asked
- What does Carbon13 invest in?
- Carbon13 invests in very early climate-tech startups it helps co-found, spanning energy, food, the built environment and materials, all aimed at cutting greenhouse gases. Water is a small slice: (don't) Waste Water tracks 2 water companies across 2 deals, including the methane-from-water venture Bluemethane.
- Is Carbon13 a VC, an accelerator or a venture builder?
- Carbon13 is a venture builder, which sits a step earlier than a typical accelerator. It recruits would-be founders before they have a company, pairs them into teams, and helps build the startup itself, then invests the first pre-seed cheque through its SEIS funds rather than backing a finished pitch.
- Who runs Carbon13?
- Carbon13 is led by co-founder and chief executive Dr Nicky Dee, alongside co-founder and chief strategy officer Michael Langguth. Min Dhillon, its principal, heads capital and has raised more than 8 million pounds to deploy into the ventures the programme builds.
- Where is Carbon13 based?
- Carbon13 is based in Cambridge, United Kingdom, where it grew out of the city's climate and university ecosystem, and runs a second venture-builder programme in Berlin, Germany. It builds and backs founders drawn from across the UK and Europe.
- Is Carbon13 the same as carbon-13?
- No. Carbon13 is a Cambridge climate-tech venture builder and investor. Carbon-13, written as 13C, is a stable isotope of carbon used in chemistry and NMR spectroscopy. The fund's name nods to carbon, but it is a company, not the element.