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

Abstract

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 AErø, 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.

Renewable Thermal Energy Systems: Characterization of the Most Important Thermal Energy Applications in Buildings and Industry (Report 1)

“…From 2012, the original 18,000 m 2 solar field of glazed FPCs connected to a natural gas boiler was expanded to approximately 33,000 m 2 of FPCs (Lovegrove et al 2015). After further upgrades, the Marstal hybrid RTES site now includes 75,000 m 3 of seasonal pit storage where hot water can be stored at 70°C-75°C (up to 95°C in summer), a 1.5-MWth heat pump, and a 4.4-MWth biomass burner connected to a 0.75-megawatt electric (MWe) organic Rankine cycle turbine (Lovegrove et al 2015;Backen et al 2018). The biomass burner and heat pump were recently installed to remove any dependency on the back-up fossil fuel boiler and system (Lovegrove et al 2015).…”

“…With decreasing CSP costs allowing utilization in two hybrid RTES district heating plants in Denmark (Aalborg CSP 2015b;2015a), and concern for the sustainability of biomass woodchips, Backen et al (2018) investigated whether the Marstal hybrid RTES district heating plant could be further improved with the addition of PTCs, and if the biomass consumption could be reduced significantly. Figure 6 shows the additional PTC field with a life of 25 years to increase the efficiency and annual operation of the organic Rankine cycle turbine and feed the excess heat to the district heat network, thereby reducing the fuel consumption of the biomass.…”

“…Figure 6 shows the additional PTC field with a life of 25 years to increase the efficiency and annual operation of the organic Rankine cycle turbine and feed the excess heat to the district heat network, thereby reducing the fuel consumption of the biomass. The total investment cost of the PTC solar field of 8,088 m 2 was estimated to be $2.48 million in 2017 (Backen et al 2018) (i.e., a fully installed cost of $307/m 2 ). Under the study's conditions, it was found that the fuel savings from the biomass and the electricity generation from the organic Rankine cycle turbine revenues, the net present value of the addition of the PTC was negative, and that the simple payback was nearly 31 years (Backen et al 2018).…”

“…The total investment cost of the PTC solar field of 8,088 m 2 was estimated to be $2.48 million in 2017 (Backen et al 2018) (i.e., a fully installed cost of $307/m 2 ). Under the study's conditions, it was found that the fuel savings from the biomass and the electricity generation from the organic Rankine cycle turbine revenues, the net present value of the addition of the PTC was negative, and that the simple payback was nearly 31 years (Backen et al 2018). The increased hybridization effort was found to be economically unviable, even at the end of the 25-year life.…”

“…The increased hybridization effort was found to be economically unviable, even at the end of the 25-year life. But, if the hybrid RTES including the PTC was moved to Turin, Italy, which has significantly better direct normal irradiance, and assuming the same fuel costs and electricity prices, the simple payback drops to 14 years, and the hybridization is nearly economically viable at a positive net present value of 26 years (Backen et al 2018). Depending on the fuel source (e.g., natural gas in the United States), even inadequate global horizontal irradiance and direct normal irradiance areas, this type of hybrid RTES could be viable.…”