The Stockholm Biochar Project is turning the city’s park and garden waste into renewable energy for heating while sequestrating carbon.

The Swedish capital of Stockholm is building a pyrolysis plant, which allows the city to produce biochar and renewable energy from its green urban waste. By 2020, the energy generated from biochar production will be turned into 25,000 MWh of heat for the city’s district heating network, enough to heat 400 apartments.

25,000 tonnes of CO2 will be sequestered by 2020 in the Stockholm Biochar Project

Cities100 – 2015

With current levels of global greenhouse gas emissions, there is an urgent need to lower the level of carbon dioxide in the atmosphere. The Stockholm Biochar Project does just this by turning park and garden waste, which contains carbon taken up through photosynthesis, into biochar. Biochar sequesters carbon by converting it into a stable element of the soil that can stay in the ground for millennia. The biochar substitutes for finite materials, such as peat, clay, and sand, and is used by the city in public plant beds – creating the world’s first urban carbon sink. The Stockholm Biochar Project plans to produce 7,000 tonnes of biochar by 2020, which sequesters carbon equivalent to the yearly CO2 emissions from 3,500 green cars.

The challenge

Cornell University estimates that producing biochar from biomass – such as organic waste that does not compete with food production or increase land use – could sequester carbon equivalent to 12% of the global CO2 emissions, which is on par with emissions from the global transport sector. As any type of clean organic material can be used to make biochar, the Stockholm Biochar Project paves the way for cities to create urban carbon sinks form their organic waste.


Economic Park and garden waste is difficult and costly for Stockholm to dispose of. When processed by the Stockholm Biochar Project, this waste can help lower the overall cost of waste management and generate an income from selling heat.

Environmental 6,500 tonnes of organic waste will be turned into a resource every year by the Stockholm Biochar Project.

Social The project aims to have 100,000 residents using biochar in their gardens by 2020.

About Stockholm

Stockholm is the capital of Sweden and the most populous city in the Nordic countries and the city stretches across fourteen islands. Stockholm is the cultural, media, political, and economic centre of Sweden. It is an important global city, and the main centre for corporate headquarters in the Nordic region. One of the city’s most prized museums, the Vasa Museum, is the most visited non-art museum in Scandinavia. The Stockholm metro, opened in 1950, is well known for its decoration of the stations; it has been called the longest art gallery in the world.

View profile

Global Goals addressed