Dec-NET - A new decentralised negative emissions technology based on flexible production of heat, biochar and CO2

In order to limit the consequences of global warming, it is imperative to drastically reduce global CO2 emissions. Negative emission technologies (NET) based on bioenergy can make an immense contribution to this. For this reason, a new concept for a coupled NET technology using a multifuel biochar furnace for flexible biochar and heat generation from forest and agricultural residues and CO2 capture from the flue gas by calcium looping is being developed (TRL2) and experimentally investigated at component level (TRL3) as part of the Dec-NET project. A consortium of three scientific and two industrial partners is involved in the project. The aim is to develop an overall concept for decentralised systems in the medium power range (0.5-3 MW). On the one hand, a demand- and seasonally optimised operation of the furnace with the production of heat and biochar should be possible, on the other hand, biogenic residues should be utilised, thus laying the basis for an economically and ecologically feasible operation of the plant. The separation/storage of carbon is realised by the biochar and the CO2 separation from the exhaust gas in the calcium looping process. An important milestone in this project is also the development of the calcium looping reactor, which is to be realised for the first time as a fixed-bed reactor and can therefore now also be used economically for decentralised biomass plants. For the flexible production of biochar and heat, an existing lab-scale multifuel biomass furnace is to be enhanced with a flexible pyrolysis gasifier mode. In experimental research campaigns, the system components combustion and calcium looping reactor will initially be analysed individually in detail. Finally, a coupling of the two components is to be realised and tested on a laboratory scale. A techno-economic analysis will provide insights into the possible applications and economic operation of the overall concept as well as the potential utilisation of the biochar and CO2 products. Dec-NET as a decentralised CO2-negative plant technology based on the valorisation of biogenic residues for the flexible provision of heat, biochar and CO2 as well as concept studies for their storage and/or use will make an important contribution to achieving the climate targets regarding the reduction of CO2 emissions. The project makes it possible to expand Austria's globally leading role in bioenergy and make it fit for the future with the development of NET technologies as well as the production of biochar and bio-CO2.