Refining long-term operation of large hydro–photovoltaic–wind hybrid systems by nesting response functions

Abstract

The traditional long-term operation models of hydro–photovoltaic (PV)–wind hybrid systems (HPWHSs) were formulated on the basis of monthly or ten-day time-scale, and they failed to describe intraday stochastic and fluctuating features of the PV and wind power, resulting in sub-optimal operating rules. To address this issue, we proposed an effective method to refine long-term operating rules for the large HPWHS by nesting a set of response functions. These response functions were derived based on numerous daily operation results, characterizing relationships between long-term hydropower output and residual load, operational risk, and electricity curtailment metrics, respectively. A large HPWHS located in the upper Yellow River basin, Qinghai province, China was selected as a case study. Results showed that the refined operating rules could decrease curtailment rate of the new energy from 17.5% to 9% compared with a standard operation policy. Meanwhile, energy production of the HPWHS and its generation guaranteed rate were increased by 7.7% and 72.7%, respectively, and the residual load fluctuation and operational risk rate were reduced by 35.6% and 23.3%, respectively. Therefore, the proposed long-term operation method is effective for guiding the complementary management of the large HPWHS.