Aerial photo of the Avedøre 1 CHP plant
In Denmark, 30 percent of all energy consumed comes from renewable sources, and the country intends to increase this percentage to 50 percent by 2030 with the long-term goal of becoming a low-emission country, independent of fossil fuels by 2050. Denmark is far ahead in the process of changing its heat and power production from coal-fired combined heat and power plants (CHP) to renewable energy such as wind, solar and geothermal, supplemented with CO2 neutral bioenergy (biomass, biofuel and biogas).
With 70 percent of the renewable energy consumption in Denmark being bioenergy-based, this offers the opportunity to change the bioenergy from being CO2 neutral to being CO2 negative by implementing carbon capture and storage.
So far technology used for carbon capture and storage has been way too expensive, and previous attempts at implementing the technology at CHP plants have been abandoned.
Now, a techno-economic study of the feasibility of a future integrated CO2 neutral energy system, where the subsurface is utilised 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 programme EUDP.
“The study looks very promising so far, and the technology used seems to be technically feasible for major CHP plants based on biomass, and with heat recovery for district heating, the economic feasibility has improved dramatically”, says Ramboll engineer Thomas Paarup Pedersen, who is part of the core research team.
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 metres depth. 30 years injection of 1 million tonnes/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 tonne of CO2 captured.
The final results of the research project will be presented at the TCCS-10 conference in Trondheim in Norway on 17-19 June 2019.
The Geological Survey of Denmark and Greenland (GEUS) is an internationally oriented, independent research and advisory institution established in 1888 within the Danish Ministry of Climate, Energy and Building. GEUS carries out activities to exploit and protect geological resources in Denmark and Greenland. Primary activities are mapping, compilation and storage of data, research, monitoring and consultancy within water, energy, minerals and climate and environment. This includes research and technology development in relation to administration of legislation. GEUS also undertakes assignments related to energy, minerals, water, climate and the environment on a contractual basis for other public authorities, research agencies, private companies and clients outside Denmark. In 2018, GEUS had a staff of 285 of which 193 hold a PhD or MSc degree, and 54 PhD students and 48 MSc students were attached to GEUS for research training. GEUS received the HR Excellence in Research from the EU commission in 2018.
The Technical University of Denmark (DTU) is one of Europe’s leading technical universities with more than 1600 scientific staff members and 1000 Ph.D. students. The Department of Energy Conversion and Storage (DTU Energy) was created in 2012, building on existing DTU world-class expertise in fuel cells, electrolysis, polymer solar cells, batteries, hydrogen storage and related technologies. DTU Energy has more than 20 years of experience in solid oxide fuel cell (SOFC) research and advanced functional ceramics. DTU Energy holds world-class expertise in electrolysis and fuel cells, polymer solar cells, batteries, hydrogen storage, thermal energy storage and a range of related technologies. DTU Energy thus has a long experience in R&D within important technologies of the future sustainable energy system. In particular, DTU Energy has worked jointly with industry on spectrum of electrolysers (power-to-gas), fuel cells, batteries, solar cells and thermoelectric devices. The department has a long experience with energy storage technologies and modelling of how such technologies can be optimally integrated in the energy system.
SINTEF Energy Research is a legal entity affiliated to the SINTEF Group, which is the largest independent research organisation in Scandinavia with more than 2000 employees. SINTEF is a non-commercial organisation where the income is almost fully generated through contract-based projects acquired in competition with others and financed by industry alone or together with the Research Council of Norway, EU programmes and other national and international financing bodies. SINTEF Energi AS (SINTEF Energy Research) is an applied research institute dedicated to creating innovative energy solutions. SINTEF Energy Research is focusing on electrical and thermal energy throughout the whole chain from sources via transport, power generation, transmission, conversion techniques, distribution and end-use. SINTEF Energy Research has a leading national position as an RTD provider and has through the years been involved in and led several large national and international research projects. During the last fifteen years SINTEF Energy Research has built up a large competence and experience and project basis within CO2 capture and transport. SINTEF Energy Research has 240 employees.