Benefits of Stochastic Scheduling for Power Systems with Significant Installed Wind Power

Wind energy on a power system alters the unit commitment and dispatch problem, as it adds a stochastic element due to the uncertainty of wind power forecasts. By explicitly taking into account the stochastic nature of wind power, it is expected that better schedules should be produced, thereby reducing costs on the system. This paper compares a stochastically optimised unit commitment and dispatch solution with a deterministically optimised solution. These are also compared to a case where perfect forecasting of wind and load is assumed. Using a planning model for the Irish system, it is shown that the schedules produced by stochastically optimising give a system cost less than that produced by deterministically optimising, if the same forecasts are used. The solution obtained when perfect forecasting is assumed is used as a base case for comparison. By examining unit operation, as well as interconnector usage, the reasons for the reduction in cost can be seen. It is also shown that using stochastic optimisation produces solutions which are better at meeting load and reserve targets.