Assessing the contribution of demand side management to power system flexibility

The increasing penetration of renewable energy sources, particularly wind power, raises concerns about the level of flexibility needed to cope with the inherent variability and uncertainty affecting these sources of energy. Departing from the common conception of providing flexibility using fossil-fuelled generators with fast ramp rates, this paper explores the use of demand-side resources. A technique to optimize the balance between the flexibility provided by fast generating units and the flexibility achievable from demand side management (DSM) is presented. This methodology is based on an extended unit commitment optimization that considers both short- and long-term aspects, i.e. operational and investment costs. The methodology is applied to the IEEE RTS (RTS-96), using actual demand and wind profiles from central Scotland.