Impact on power factor by small scale renewable energy generation

Abstract

Domestic installations traditionally were believed to be resistive in nature and did not affect power factor much, if at all. With increasing affordability of air-conditioners, and replacement of electrical geysers with heat pumps, loads are becoming more inductive. Small-scale renewable energy generation through e.g. solar photo-voltaic (PV) panels are becoming more affordable and as such are connected to the grid - with or without the utility's knowledge and approval. The South African Grid Code requires that PV systems of categories A1 and A2 generate electricity at unity power factor. This implies that only real power is generated. Any reactive power, if not generated by the consumer, must be provided by the utility. In this paper, the impact on power factor control by small scale renewable energy generation is illustrated through practical examples. Small-scale renewable energy generation at unity power factor creates a burden on the utility for the provision of the required reactive power. This may result in the utility not being able to recover revenue for the provision of services and increased technical losses. Regulatory reform may be required to address this shortcoming. The paper also raises the question whether electricity must still be sold as kWh, or perhaps as kVAh.