The grand challenge to be addressed is the decarbonisation of food production by valorisation of waste streams. Specifically, for recycling heat and CO2, the main challenges are:
- Capture, separation, and distribution of CO2, including balancing supply and need over time
- Integration of recycling systems for heat and CO2 for resource efficiency
- Business models for use of CO2
These innovations do not require new technology to be developed. Rather, it is a question of new applications of technology and of system optimization.
The need to use low-grade heat arises from the previous sale of all higher-grade heat to district heat, which is a widespread practice in Sweden. To achieve the required capacity, the heat recycling must be designed for a 45-55°C supply and 25°C return. This is achieved by adding ventilation heat to the standard radiative heat, thus adding more area for radiative heat. To use the CO2 from the pulp and paper plant, harmful substances must be removed, notably NOx (harmful to plants) and CO (harmful to humans), and unknown substances need to be identified and analysed. N2 and water vapor hinder pressurized storage for daily balancing so, both must be removed. Several suppliers of separation technology have offered systems for separation which all technologies are evaluated. For the project, the main modification is both the continued analysis of technical and economic viability of different solutions for providing the greenhouse with CO2 through CCU from flue gases, and to guarantee that the correlating solution meets safety standards for workers and plants in the greenhouse, besides lessening costs and environmental impacts.