Zero energy level and economic potential of small-scale building-integrated PV with different heating systems in Nordic conditions

Excess solar power provided part of the space heating (SH) needs in spring and autumn and most domestic hot water (DHW) needs in summer. Self-consumption was increased by 15…70% with EH and by 20…40% with HP, when a PV system was used for space and DHW heating during summer and midseasons. Thermal storage increased energy matching, but high storage capacities did not provide a significant improvement over lower ones. Levelised cost of energy (LCOE) for PV electricity in a single building almost reached grid parity (11 c/kWh) using EH, but the generation cost for HP and DH remained higher (13 and 17 c/kWh, respectively). Investment incentives reduced the LCOE below grid prices for electrically heated systems. In the community, the economies of scale lowered LCOE, such that in many cases grid parity was reached even without incentives.