Effects of Variable Renewable Energy Sources (VRES) Integration to the Unit Commitment of Dispatchable Thermal Generators

Abstract

Variable renewable energy sources, such as photovoltaic (PV) and wind generator, would create the need for more flexibility to the existing power system. Concerning the unit commitment of dispatchable generators, the start-stop frequency of generators would increase if more PV or wind generation integrates in the power system. This paper discusses how much increment of the start-stop frequency is expected due to PV and wind power integration by using real data of the demand, the PV power, and the wind power in the north-east area of Japan for seven years (2008-2014 fiscal years). Two different types of approach, ‘the simulation method’ and ‘the demand wrinkle stretching method’ are used for evaluating the start-stop frequency of dispatchable generators, and results are around 30% increment of start-stop frequency for the 30% PV integration and around 40% increment for the 20% wind power integration.