An investigation into the financial impact of residential Rooftop PV on Stellenbosch Municipality

[摘要] ENGLISH SUMMARY : Worldwide, electricity utilities are recognising and responding to the threat that a large uptake of rooftop photovoltaic (PV) solar installations might have on their traditional business model, based on volumetric sales. Likewise, in South Africa there is a concern that the trend of households investing in rooftop PV might have significant impact on the business model of electricity delivery services by Eskom and local governments. Since South African municipalities are responsible for managing electricity distribution, they face similar challenges to traditional energyutilities across the world. Historically, South African municipalities served as localdistributors of electricity and many municipalities relied on the revenue generated from electricity sales to cross-subsidise other services that wereunderfunded. If thenumber of rooftop PV installations continues to rise in South Africa, this might have anegative impact on the financial balance of South African municipalities. Thisresearch investigates the financial impact that increasing installations of gridconnectedrooftop PV at a household level might have on local governments, usingStellenbosch Municipality as a case study. An extreme-case scenario approach isused to measure the financial impact. Assumed in this scenario is that the absolutemaximum of installed embedded generated electricity, as set by NRS standard, willbe channeled back to the grid by households. The NRS standard provides a guide asto how much maximum installed embedded generated electricity can be fed to thegrid before an in-depth grid study needs to be conducted. The research looksspecifically at the residential areas in Stellenbosch with high electricity use,determined by an examination of the electricity use in the different suburbs.Moreover, criteria are set to determine which households from these high electricityuse suburbs may be regarded as potential investors in solar rooftop PV. If thesecriteria are applied, it means 541 households could (each) potentially connect a 3 kWp rooftop PV system. This leads to an annual reduction of approximately ZAR 1.3million in the municipality's expenditure for the electricity supply from Eskom. It alsoleads to a loss in income of ZAR 3.7 million by the municipality as a result ofelectricity sales reduction, resulting in a net loss of ZAR 2.4 million. The net losswould be equivalent to a 0.6% financial reduction on the total electricity revenue ofZAR 413.7 million for the municipal financial year 2013/2014. If the maximum gridcapacity approach were practised, this would mean 2 255 households would be ableto connect a 3 kWp solar system to the grid. This would result in a loss in income ofZAR 15.3 million and a saving of ZAR 5.5 million. The net loss would be ZAR 9.8million, which would be equivalent to a 2.4% reduction on the total electricity revenueof ZAR 413.7 million for the municipal financial year 2013/2014.

[发布机构] Stellenbosch University