Dynamic operating reserve strategies for wind power integration

Several research efforts are conducted towards the impact of wind power variability on the operating reserve requirements of power systems. In most systems, reserve capacity is determined by means of a heuristic or statistical analysis of the different drivers for system imbalances. This contribution puts forward a dynamic reserve approach in which the operating reserve capacity is modified on hourly basis, based on expected wind power conditions. This would improve the current methodologies where the capacity is fixed for longer periods, avoiding expensive overestimations. By means of a decentralised approach, the suggested methodology conforms with an unbundled and liberalised market framework. Results show how the average upward and downward capacity reductions are reduced with at least 36% and 16%, compared to the corresponding static reserve strategy. System simulations integrating this dynamic reserve strategy reveal substantial reductions in operational costs. The average cost of withholding reserve capacity is observed to decrease from 4.5, 5.1, 17.1 and 51.2 to 3.1, 4.8, 7.9 and 14.6 €/MWh wind energy injected, respectively, for an installed capacity representing 6, 12, 18 and 24% of the annual electricity demand. In conclusion, the results of this contribution encourage transmission system operators to evolve towards dynamic reserve strategies.