Economic Optimization of PV System Orientation under Evolving Electricity Price Profiles in Nordic Detached Houses

Abstract

The rapid growth of photovoltaic (PV) systems has altered electricity market dynamics through increasing midday price depressions associated with the so-called “duck curve” phenomenon. Consequently, the economic performance of PV systems depends increasingly on the temporal alignment between production, consumption, and electricity prices. This study examines how evolving hourly electricity price profiles have influenced the economically optimal orientation of residential PV systems in Finnish detached houses. The analysis combines measured hourly electricity consumption data from 22 households with simulated PV production profiles derived from PVGIS data (2012–2023) and historical electricity prices from 2020 to 2025. PV production was simulated for system orientations ranging from 45° east to 45° west in 5° increments for four typical system sizes (3–12 kWp), and annual savings were calculated by combining hourly production, consumption, and spot price data. The results indicate a gradual eastward shift in the economically optimal orientation, particularly in 2025, reflecting increasing price differences between morning and midday hours, although the economic impact remains limited (below 0.3%).