Thermo-economic and environmental analysis of integrating renewable energy sources in a district heating and cooling network

This paper presents the technical, environmental, and economic evaluation of integrating various combinations of renewable energy sources-based systems in the expansion of a district heating and cooling network of a Technology Park near Barcelona in Spain. At present, a combined heat and power plant running on fossil fuels serves the heating, cooling, and electricity demand of the Park. However, this energy demand is expected to increase substantially in the coming years. EnergyPRO software was used to model the energy demand growth till 2030. Validation of the software application was done by making a base model using real plant data from the year 2014. The software was then used to project the energy supply based on three 15-year scenarios, having different combinations of renewable energy technologies, from 2016 until 2030. Primary energy consumption, CO₂ emissions, and the net present value obtained in each scenario were used to decide the best combinations of renewable energy sources. The results of the study showed that presently, biomass boilers combined with absorption chillers and supported with solar thermal cooling are the most competitive technologies in comparison to ground source heat pumps for large DHC networks. This is mainly because of the lower primary energy consumption (624,380 MWh/year in 2030 vs. 665,367 MWh/year), higher net present value (NPV) (222 million € vs. 178 million €), and lower CO₂ emissions (107,753 tons/year in 2030 vs. 111,166 tons/year) obtained as a result of the simulations.