Hybridization of concentrated solar power and biomass combustion for combined heat and power generation in Northern Europe

Decreasing installation costs and maturing of the technologies associated with concentrated solar power pave the way for new areas of application. One possible application could be district heating systems, which are especially common in Nordic countries. The objective of this paper is to evaluate the prospects of retrofitting an existing district heating plant located in Northern Europe with parabolic trough collectors. The study investigates the techno-economic feasibility of hybridization with parabolic trough collectors. For this purpose, a computer model of an existing district heating plant, located on the Danish island of Ærø, was developed. The model allows annual simulations of energy flows within the system. Validation of the model against measured data from the operational year of 2016 indicates agreement between simulated results and measured data within an accuracy of ±3.5 %. After validation, changes in the control strategy and the plant layout are implemented in the model. The sizing of the collector field is described and the results of annual simulations are presented in terms of electricity- and heat production. Due to a payback period of 31 years, it is concluded that such a hybridisation is economically infeasible under present conditions, but could become attractive when investment costs are lowered or a higher tariff for the electricity produced is granted. Furthermore, it is indicated that in a case, where the location of the plant is changed to Torino, Italy, the economic results increase significantly with the simple payback period lowered to 14 years.