Improved photovoltaic self-consumption with appliance scheduling in 200 single-family buildings

Self-consumption of on-site photovoltaic (PV) electricity in buildings is gaining interest as a way to accommodate high PV penetrations in the power system. On markets where there is no substantial feed-in support for renewables, there is also an economic incentive for PV self-consumption, as selling prices for PV electricity are normally lower than retail electricity prices. One option for improved self-consumption is rescheduling of programmable appliances, typically washing machines, clothes dryers and dishwashers. This paper determines the potential to increase PV self-consumption through scheduling of these appliances in Swedish single-family buildings. Simulations of daily load scheduling were performed to match on-site PV power generation and recent (2008–2012) hourly electricity market prices, using a set of high-resolution (10-min) appliance load profiles from 200 monitored Swedish households. Since these data provide appliance ownership and daily appliance use patterns in a wide range of households, a realistic upper limit to the self-consumption potential is obtained. The conclusions are that load shifting can potentially increase PV self-consumption by around 200 kWh on average, corresponding to a few percent of the total PV power generation for the system sizes studied (3–9 kWp). The maximum economic benefit over the studied years was 20 EUR per year and household. For the larger PV system sizes that could inject critical peak powers to the distribution grid, the peak hourly PV surplus decreased less than a few percent. The main conclusion is that there is an overall low potential for improved self-consumption through optimal scheduling of the studied appliances, at least with the current Swedish market conditions.