Solar powered net zero energy houses for southern Europe: Feasibility study

► NZEB implementation is feasible, with a moderate cost increase. ► All NZEB solutions obtained had a similar solar thermal system size. ► Grid-connected PV system panel area varied and between 11m2 and 38m2. ► Micro-generation subsidized have fast paybacks, independently of system efficiency. ► The micro-generation government subsidy does not promote efficient solutions. This study explores the feasibility of solar Net Zero Energy Building (NZEB) systems for a typical single family home in the mild southern European climate zone. Using dynamic thermal simulation of two representative detached house geometries, solar collector systems are sized in order to meet all annual energy needs. The impact of variations in building envelope, occupant behavior and domestic appliance efficiency on final energy demand and solar NZEB system size is analyzed. After sizing a set of solar thermal (ST) and photovoltaic (PV) solar systems, an analysis was performed to identify the best system configuration from a financial and environmental perspective. The cost and performance of the NZEB system shows low sensitivity to the size of the ST system, whenever solar hot water is used to its maximum. The introduction in the analysis of a micro-generation government incentive scheme shows great potential for financially attractive NZEB homes in this climate zone.