Introduction: BIOCHAR for carbon sequestration
Biochar offers a stable and persistent form of carbon, produced from pyrolysis (thermochemical treatment at high temperature and anaerobic conditions). It is a key Land-based Mitigation Technology (LMT) because of its wide applicability and high global potential for both carbon sequestration and emission reductions. By offering a wealth of applications that contribute to numerous ecological functions and multiple sustainable development goals, low and high-income countries alike are considering biochar as part of their strategies. Biochar is among the most cross-cutting and cross-sectoral of all negative emission technologies (NETs), as it can include multiple components and application options across a wide variety of deployment and implementation schemes.
Stockholm Biochar Project
An innovative project in Stockholm (Sweden) exhibits the cross-cutting and cross-sectoral nature of biochar application. Farm and garden wastes are gathered to provide biomass for conversion into gas and biochar through pyrolysis. The gas is used within the city’s district heating system while the biochar is used to sequester carbon, enhance tree-planting, and provide soil benefits for farmers. In addition to the climate and ecological benefits, the project has also suggested innovative and complementary partnerships between urban and rural areas. There is considerable interest in the approach for cities elsewhere in the EU and a replication manual was developed for this purpose. There is a voluntary European Biochar Certification system for quality assurance to promote best practices.
Biochar in East Africa
Biochar has benefits that are potentially even greater in tropical climates and soils, where increased yields and other benefits add to the proven carbon sequestration and climate mitigation benefits. However, unlike northern Europe, it is more difficult to find applications or demand for pyrolytic gas, and therefore one approach to the biochar innovation system has been to rely on household-scale gasifiers that can be used for household cooking, while the biochar is used by local farmers. Consequently, scaling up biochar use faces significant transaction costs as well as logistical barriers. The possibility of deploying larger-scale systems could reduce these transaction costs as well as offering more cost-effective biochar production. The African-EU partnerships on energy and agriculture offer some opportunities for technology transfer to support upscaling options while at the same time the specific applications chosen can benefit from out scaling across different geographies.
