We’ve moved!



By car:

Parking is available outside.
Waze user? Use these automatic directions.

By commuter train:

Take the train to Ulriksdal Station (check trains at sl.se). From there it’s a brisk 9-minute walk.


Made in sweden

Zero Energy Hydrothermal Carbonization

Superefficient sludge disposal

Presenting a revolutionary new way to convert wet sludge into biofuel


Wastewater sludge, industrial sludge, wet biomasses – it's a problem that has to be dealt with. We are busy developing a robust industrial-strength process to convert all that sludge into a valuable asset called biocoal.

We use a proven method – hydrothermal carbonization – but with several innovations to turn it into what is probably the most efficient sludge disposal method for the 21st century.



Swedish Energy Agency provides €2.2M in funding

C-Green has been granted funding to develop a full-scale sludge-to-biocoal reactor in cooperation with Stora Enso. Read the Swedish or English press-release for more information.


#SET100 List 2018

C-Green selected as one of the best 100 start-ups working on the global energy transition. See the full list of finalists, read about the competition, and check out the jury.



Our goal is to turn hydrothermal carbonization into a modern and cost-effective solution for almost any wet biomass sludge problem. Through innovation and modern industrial design, we feel that our Zero Energy HTC offering will become the new environmental benchmark for almost all sludge disposal problems. 


Impressive Dewatering

Go from 70-90 % water content down to 30 %, without using any external heat. It's simply the most efficient way to dry large quantities of wet biomass on the planet!

Zero Energy HTC

Our own patented invention to reduce the traditional heavy-energy HTC to a process with basically no need for external energy.


The high pressure and temperature eliminates bacteria, fungi, and viruses. The result is an odor-less and sterilized hydrochar.


High capacity

Process up to 50 tons of sludge per day on a space equivalent to 5 parking spaces.

Making fuel

HTC turns wet sludge into a dry economic biofuel with excellent energy properties. It's ideal for use in a biofuel heat and power plant.


Our Zero Energy HTC process is continuous, and uses our own patented FracFlow reactor design. The result is ease-of-use and better performance than traditional HTC.


The new sludge

This is what it looks like. Our HTC process efficiently turns wet biomass into a dry hydrochar product using a minimum of external energy. The process kills bacteria, fungi, viruses, and immediately stops greenhouse gas emissions caused by organic decomposition.

The hydrochar is perfectly suited as a biofuel in a modern heat and power plant.



Dry | moisture level around 30 %.

Valuable | high energy content equal to standard wood-based biofuels.

Sterile | hygienic, safe and easy to transport.


Almost there...

and soon you'll know everything

CGreen_Container_40HC Side W4.jpg

But for now, we'd like to keep things under wraps a little bit longer. Our team has extensive experience with industrial process design, and we know the time required to design a product for heavy industrial use. And we want to make sure that we've tested (and retested) everything so that we can offer the best product possible.

However, if you're interested in our unique HTC solution for sludge disposal, or have a pressing sludge problem that has to be solved, please don't hesitate to contact us! We have plenty of more information to share after an initial contact.

For more information, or an invitation to our main website

Please contact us at