The performance of nearly-zero energy buildings with onsite generation systems as heat and electricity prosumers in the energy system

Energy planning and management in the built environment should progress towards the net zero or nearly-zero energy balance in a cost-effective manner. To do so, the performance of highly energy-efficient buildings with modern technologies needs to be thoroughly studied. To that endeavor, this study investigates the use of onsite surplus electricity to drive heat pumps and export the heat, instead of directly exporting onsite surplus electricity to the grid. Thus, the objective of the dissertation is to investigate the potential of heat and electricity prosumers to improve the energy balance and reduce the operational CO2 emissions in the built environment while maintaining energy quality. This study employs simulations based on an existing building and on a reference building, as well as multiobjective optimizations for lifecycle costs, CO2 emissions and exergy of residential-scale energy systems with onsite electricity and heat generation components. It investigates which system configurations offer the best performance, and evaluates whether the export of heat can make a significant contribution to this end. Moreover, two different energetic, economic and climatic contexts are explored: the Netherlands and Finland. The results show that heat and electricity prosumers, where surplus electricity is used to drive a HP and export heat, can provide optimal solutions for lifecycle costs and CO2 emissions in the Netherlands and Finland. This, however, comes with a significant drop in exergy content when converting electricity into heat.