Impact of residential electricity tariffs with variable energy prices on low voltage grids with photovoltaic generation

• The impact of different tariffs on low voltage grid stability is modelled.
• Different levels of photovoltaic generation are considered in the analysis.
• Metered data is used to reflect residential demand response to electricity prices.
• The tariff setup is crucial to avoid aggravation of critical grid situations.
• Central market signals alone may not be sufficient to support local grid stability.

This paper presents an approach integrating simulation models for residential electricity demand with price elasticity and electricity generation from photovoltaic systems as well as for load flow analysis using Monte Carlo simulation in low voltage distribution grids. The price elasticity model, using metering data collected within a field test including approximately 1100 households, and the application of the approach for analysing the impact of alternative electricity tariffs on grid utilisation for different use cases constitute the main contribution. We compare a tariff using constant prices with tariffs using variable prices, one of which is directly derived from the central wholesale market, while another one is subject to sales-driven rules and regional renewable electricity availability. The results reveal that generation peaks lead to power flow reversions and an exceedance of the limit for voltage deviation in several hours for high photovoltaic installation rates and thus to more critical situations than demand peaks for the considered low voltage grid. While the considered tariffs can, generally, support grid stability, several drawbacks should be reduced in future tariff design: the considered sales-driven tariff may aggravate critical grid situations during demand peaks while a tariff, solely deriving its variable prices from a central wholesale market, may not be suitable to relieve critical grid situations during distributed generation peaks.