Evaluating the Self-Balancing Potential of Rooftop Photovoltaic Systems and its Impact on the Net Demand Profile

Abstract

This paper investigates the self-balancing potential of rooftop Photovoltaic (PV) systems in Finland by focusing on the characteristics of the net demand for the electricity network scenario of the year 2045. Four comparative cases are analyzed related to the PV panel orientations, including south facing panels, southeast-southwest facing panels, east-west facing panels, and PV panels aligned with the actual rooftop orientations i.e., with the roof pitch and roof azimuth. The findings indicate that east-west facing or actual rooftop facing PV systems reduce the average mid-day overgeneration by 38% and 44% respectively as compared to the south facing PV systems, thus minimizing the need for balancing. The study further reveals that despite the increase in frequency and uncertainty of the net demand ramping events associated with the integration of PV generation, orienting the PV panels towards east-west or actual rooftop orientations results in reduced ramp rates and ramp occurrences as compared to the south facing PV systems. The analysis also indicates that rooftop PV systems result in a 53% reduction and east-west facing PV systems result in an even higher reduction of 61% in the average magnitude of the evening ramp rates. The paper also analyses the interactions between PV and other non-dispatchable generation resources, such as wind power on the net demand profile to do a holistic assessment for balancing measures. The paper finally concludes that rooftop PV panel orientations and east-west PV panel orientations aid in shifting the generation towards the demand interval.