Department of Design

Helsinki Biochar Project

The City of Helsinki explores the practical pathways for improved carbon sequestration, circular waste systems, and thriving urban vegetation via increasing the use of biochar on selected demonstration sites across public green structures. During years 2022-23, different kinds of organic waste materials are being tested as potential feedstocks for manufacturing local biochar. The project is set out to spread awareness about the benefits of, and providing practical know-how of using biochar among the city administration and citizens.
Fine biochar made from reed plants harvested from Helsinki in September 2022
Biochar made from common reed

Biochar to reach a climate- neutral city

The city of Helsinki has set an ambitious program to be carbon neutral by 2030, and all means necessary need to be taken to achieve that goal. Emissions are being cut throughout the city and to reach the target, 20 % of emissions, equalling to 702 kt CO2- eq., can be compensated. By 2040, the city will offset all remaining emissions through carbon sinks located within the city´s geographical boundaries, which is where biochar is needed

In addition to a means to sequester carbon, biochar has potential to play a role in climate adaptation strategies. Biochar can be added as a soil amendment changing the absorption capacity and structure of the soil. Increasing the capacity of urban soils to be more resilient to extreme weather events, such as storms and prolonged periods of drought, could potentially serve as one of multiple means for urban climate adaptation. 

Intended experimental sites in Helsinki

Currently, a number of sites that are currently being designed for construction have been selected to be amended with biochar. The list is evolving, and the plans are subject to change. The information in the list is constantly being updated.

Citizen engagement in biochar related activities

Because biochar is still a relatively unknown material, the Helsinki Biochar Project aims to increase the awareness of citizens on the potential of biochar. In order to do so, the project strives to set up a series of trials in the Helsinki metropolitan area to demonstrate the various stages of the biochar cycle to citizens, ranging from showcasing the production of biochar from local waste streams, how it works as a means to sequester carbon and finding engaging ways to utilise the material as a climate adaptation tool. The goal of the Helsinki Biochar Project is to demonstrate that converting local waste streams into responses to climate change is not just a distant process for decision makers only, but can be an engaging capability-building activity for citizens as well.

The Helsinki Biochar Project builds on previous collaboration projects on biochar

Carbon Lane -project

Carbon Lane (CarLa) is an EIT Climate-KIC funded project which takes place during 2019. The project explores practical carbon drawdown solutions for urban green areas

Illustration of a tree in soil with details of roots, carbon, nutrients

Hiilipuisto - Carbon Park

Hiilipuisto project launches scientific monitoring of biochar-based planting soils and develops sustainable practices in the green building sector.

Kuva: Esko Salo
City of Helsinki
Aalto University
Helsinki Region Environmental Services HSY
VTT Technical Research Centre of Finland Ltd

Project responsibles

  • Susanna Kankaanpää, Helsinki Urban Environment Division, Climate Unit
  • Prof. Mikko Jalas, Aalto University

Contact persons:

  • Tuuli Markkanen, Project Coordinator, Aalto University tuuli.markkanen[at]
  • Will van Twuijver, Coordinator in citizen engagement, Aalto University, will.vantwuijver[at]


Useful sites to read and follow regarding biochar use in urban green structures

Urban Biochar work in other cities

Several cities across the globe have started initiatives to promote biochar use to fight climate change.

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