Large combined heat and power plants in sustainable energy systems

• The feasibility of CHP plant types is analysed in a 100% renewable energy context.
• Three large-scale CHP types are compared in full system application.
• Four scenarios are constructed and compared in terms of system costs and fuel consumption.
• Combined cycle gas turbines plants show to be the most feasible technology.

In many countries, the electricity supply and power plant operation are challenged by increasing amounts of fluctuating renewable energy sources. A smart energy system should be developed to integrate as much energy supply from fluctuating renewable sources and to utilise the scarce biomass resources as efficiently as possible. Using the advanced energy systems analysis tool EnergyPLAN and Denmark as a case, this analysis defines which of the three assessed types of CHP plants connected to district heating systems is most feasible in terms of total socioeconomic costs and biomass consumption. It is concluded that the CCGT CHP plant is the most feasible both from a technical analysis and a market economic analysis with electricity exchange. It is found that the current economic framework for large CHP plants in Denmark generates a mismatch between socio economy and business economy as well as an unsustainable level of biomass consumption. Therefore, the regulatory framework should generally be considered in long-term planning of sustainable CHP systems.