C-Green raises SEK 40M to scale hydrothermal biowaste-to-hydrochar technology
What's the deal? Stockholm-based C-Green has raised SEK 40M (~$4.3M) in a growth equity round to scale its hydrothermal carbonisation (HTC) technology, which converts wet biowaste into hydrochar — a carbon-rich material used as biofuel, soil improver, or fertiliser input. The round, completed in June 2026, was backed by existing and new investors.
The capital will fund upgrades to C-Green's flagship full-scale HTC plant at Stora EnsoDealroom has a profile for this one. Try Dealroom →'s Heinola fluting mill in Finland, advancing its system to a next-generation "Design 3.0." The goal: reach TRL 9, or full commercial readiness.
Why now? Wastewater treatment and industrial waste regulations are tightening across Europe, driving demand for alternatives to traditional sludge disposal. C-Green's technology is designed for wastewater treatment plants, pulp and paper mills, and food industry waste streams — all sectors under growing pressure to reduce landfill dependency and recover nutrients like phosphorus and nitrogen.
The Design 3.0 upgrade aims to improve energy efficiency, boost operational reliability, and cut both capital and operating costs — steps needed to move from demonstration to repeatable commercial deployment.
What could go wrong? HTC technology still faces the classic deep-tech scaling challenge: proving that a process that works at one site can be replicated reliably and profitably across many. C-Green's $4.3M is modest for an infrastructure play with industrial ambitions across Europe and beyond. The company will likely need significantly more capital to build out a multi-site footprint.
Competing waste-to-value approaches — from anaerobic digestion to pyrolysis — are also vying for the same municipal and industrial budgets.
The signal: C-Green remains classified as early stage on Dealroom despite operating a full-scale plant, underscoring how capital-intensive circular bioeconomy infrastructure ventures can lag in fundraising relative to their technical maturity. The modest SEK 40M round — small by industrial cleantech standards — suggests the company is still bridging the gap between proven technology and the kind of project-finance-scale backing needed to replicate across multiple sites. As European regulation increasingly penalises waste and rewards nutrient recovery, the commercial case strengthens, but investors' appetite for these asset-heavy plays remains the binding constraint.
Read more: Startup Mafia
