Danish research project looks at CO2 capture of biomass-fired CHP plants

In Denmark, a new research project carried out by Ramboll, GEUS, DTU and SINTEF is studying the feasibility of using CO2 capture at Danish biomass-fired combined heat and power plants. A techno-economic study of the feasibility of a future integrated CO2 neutral energy system, where the subsurface is utilized for thermal energy supply and storage, as well as temporary CO2 storage is being performed as part of a research project carried out by Ramboll, GEUS, DTU and SINTEF. The study is supported by the Danish energy technology development and demonstration research program EUDP.

The study analyses a generic bio-plant retrofitted with a CO2 capture. The generic bio-plant is benchmarked against a reference power plant, the biomass-fired Avedøre 1 CHP plant, located in the outskirts of Copenhagen. The plant has a capacity of 640 MWth, with net electric power output of 219 MWel and district heating production of 352 MWth at full-load conditions. The plant operates with 100% wood pellets. The Avedøre plant is considered representative of a state-of-the-art power plant that has been converted from operating with coal to biomass.

In the modelling work, the bio-plant is retrofitted with so-called Monoethanolamine (MEA) capture technology, a well-known carbon capture technique of CO2 absorption by using amines. In the process, steam from the CHP production is used to regenerate the amine used to capture CO2. When leaving the capture plant, the CO2 is compressed to 110 bar, transported by pipeline 3 km towards northeast, and injected into a storage reservoir in 1300 meters depth. 30 years injection of 1 million tons/year of CO2 is feasible from one injection well. The transport and injection case is based on capture from Nordjyllandsværket CHP plant after possible conversion to biomass-firing.

The research results so far show that it is possible to recover a considerable amount of heat from the CO2 capture process to the DH system for use in the district heating system, significantly improving the thermal efficiency of the bio-plant and consequently reducing the cost of CO2 capture by roughly 30%, or from €77 to €52 per ton of CO2 captured.