Residential solar power profitability with thermal energy storage and carbon-corrected electricity prices

Abstract We study the economic profitability of residential solar photovoltaic (PV) systems in Finland. We show a moderate rate of returns (1.0% in Northern and 1.4% in Southern Finland) for the PV system investments with time-of-use hot water heating. Optimized hot water heating increases the rate of return by 0.6 percentage points. We internalize the negative externalities of greenhouse gas emissions from electricity generation by presenting the hourly electricity prices as a function of emission permit costs. A 10 €/tCO 2 increase in carbon price improves the PV investment rate of return by 0.3 percentage points.