Optimal operational state scheduling of wind turbines for lower battery capacity in renewable power systems in islands

To cover a large portion of annual electricity demand of an island with renewable power sources, battery capacity should be high because of temporal inconsistency between renewable power generation and power demand. But such high battery capacity is practically infeasible because battery forms the greatest part of the cost of the renewable power system. As an alternative solution, wind turbines can be in idle state when overall renewable power generation is high, to reduce the required battery capacity. This paper investigates the optimal operational state scheduling of wind turbines for battery capacity reduction and its effect to reduction of renewable power generation and cost. A Mixed-Integer Linear Programming problem is formulated for the scheduling. A case study shows that the decrease of renewable power generation due to idle state of wind turbines is small, even if the battery capacity becomes significantly lower.