The Stockholm Biochar Project uses park and garden waste to produce biochar and renewable energy. Biochar is a fantastic soil improver that helps the soil to retain water, air and nutrients. Once in the soil, biochar is a carbon sink that contributes to a greener city environment and reduces the levels of carbon dioxide in the atmosphere for hundreds to thousands of years to come. The energy used in the process is recovered as heat for the city’s district heating network as part of the ”Open District Heating project” – a project to recycle excess heat in Stockholm. The goal of the Stockholm Biochar Project is to produce enough heating for 400 apartments and to create a carbon sink equivalent to the annual carbon dioxide emissions from 3500 cars.
The project is being funded by the ”Mayors Challenge” – an innovation competition for cities intended to initiate and spread innovative projects, arranged by the American organization Bloomberg Philanthropies. 155 cities participated in the European version of Mayors Challenge and only five were awarded funding to implement their projects, and Stockholm was one of the five winners. The project will run for three years with the support of Bloomberg Philanthropies, aiming to spread the biochar system to more cities around the world.