Theoretical Analysis of the Combination of CSP with a Biomass CHP-plant Using ORC-technology in Central Europe

Abstract

In this paper the results of the preliminary performance assessment of an emerging hybrid CHP-technology using Organic- Rankine-Cycle technology comprising biomass combustion and concentrating solar thermal power in areas with low DNI is presented. The study was conducted in course of the research project BIOconSOLAR, which was funded by the climate fund of the Austrian government. The assessment is based on the technical design and economic conditions of an existing CHP-plant with nominal electric power output of 1.5 MW, which is located in the city Salzburg in Austria. The solar thermal energy provided by a parabolic trough collector field is primary used for electric power production in order to reduce biomass consumption and operation costs accordingly, but also to boost the thermal energy supply for the district heating of the city Salzburg. For electric power production the solar thermal energy is fed into the ORC-power cycle at a temperature level of at least 270°C. A transient simulation model of both the biomass CHP-plant and the parabolic trough plant was developed in IPSEpro. Based on the results of the process simulation the economic performance was assessed by conducting a dynamic investment calculation. Despite the technical and economic uncertainties of this preliminary assessment the retrofitting of biomass-solar CHP-plants with CSP in areas with low DNI is a promising option to improve the economic performance of about 100 CHP-plants in operation in Central Europe. A feed-in-tariff for solar thermal electricity in the same order of magnitude as for photovoltaic could trigger the retrofit of biomass CHP-plants.