Impact of forecast error of photovoltaic power output on demand and supply operation in power systems

Increasing the proportion of power generation from renewable energy sources has become increasingly important in Japan since the nuclear accident caused by the 2011 Tohoku earthquake. Photovoltaic (PV) generation in particular has gained much attention in Japan. In general, the supply and demand of electricity are maintained by economic-load dispatching control (EDC), which refers to regulation of the output of conventional (thermal or hydro) power plants to minimize their operational costs. Using the PV generation forecast in EDC, which includes the unit commitment (UC) of conventional power plants, is essential to maintain the economy and reliability of the power system with large-scale integration of PV generation. In this study, we consider an EDC that determines the UC on the basis of the day-ahead PV generation forecast. The frequency and trend of outages and power surpluses due to the forecast errors of the PV power output are evaluated.