Impact of growing national solar power capacity on the profitability of residential solar energy production in northern conditions

This study examines the effect of increasing solar photovoltaic (PV) production on electricity market prices and analyzes how this development affects the profitability of residential PV systems. The key novelty is a comprehensive techno-economic analysis of the profitability of differently oriented residential PV systems under different electricity price scenarios. The novel approach combines PV system simulation, a large set of real electricity consumption data, and two electricity price estimation methods: linear regression and aggregated bidding curve modification. Nordic conditions with long summer days and low solar elevation angles enable the efficient use of different PV system designs, such as vertical bifacial PV, offering versatile production profiles. This study identifies how rapidly PV capacity growth cannibalizes the value of the different residential PV systems, what systems are resilient toward cannibalization, and how the national PV deployment strategy affects cannibalization in Finland. The results show that even 500 MW addition to the national PV production capacity in Finland compromises residential PV profitability in the worst-case scenario. Electricity-powered heating solutions make PV more profitable. Overall, maximizing self-consumption is crucial to maintaining the economic profitability of residential PV systems in different electricity price scenarios.