From Hourly to Quarter-Hourly: Effects of Metering Intervals on Self-Consumption Ratios and Economic Viability of Solar Photovoltaic Systems in Finnish Residential Buildings

Abstract

The adoption of solar photovoltaic (PV) systems in Finnish residential buildings has significantly increased, reflecting broader global trends. A crucial element in the investment evaluation of these systems is the self-consumption ratio (SCR). Self-consumed energy reduces costs on energy purchases, taxes, and distribution system operator (DSO) fees, thus linking the SCR with profitability. This study explores the effects of transitioning from hourly to 15-minute metering intervals on SCR and the consequent financial outcomes. This research utilizes actual consumption data from 10 detached and 10 multi-dwelling buildings (MDB) in Finland and simulated production in 15-minute intervals to evaluate SCR impacts across various system sizes. Detached buildings (DB) were analyzed with system sizes of 3 kWp, 5 kWp, and 7 kWp, and MDBs with 10 kWp, 20 kWp, and 30 kWp. Results reveal SCR decreases from -0.60% to -4.52% across all DB’s PV system sizes, with corresponding financial benefits decreasing by - 1.02% to -3.67%. In MDBs, SCR decreases ranged from -0.01% to -4.61%, with financial impacts decreasing by -0.01% to - 3.41%. These findings underscore the variability of SCR influenced by metering intervals and site-specific factors such as production and consumption patterns, providing substantial data to the discourse on sustainable energy practices in residential settings.