Wind Power Providing Flexible Ramp Product

The deepening penetration of renewables in power systems has contributed to the increasing need for generation flexibility. Specifically, for short-term operations, flexibility here indicates that sufficient ramp capacity is available to respond to the varying load and intermittent generation. To address the growing needs for ramp capacity, markets for ramp products have been launched in practice such as those in California ISO and Midcontinent ISO. Sometimes, expensive fast-start units must be committed in real time to guarantee sufficient ramp capacity. Occasionally even worse, inadequate ramp capacity from the given generation portfolio might lead to curtailment of renewable generation or load shedding. Therefore, more supplies of ramp capacity are required. In fact, wind power producers (WPPs) are physically capable of offering ramp services, which gives us a potential option. In this paper, we attempt to explore the mechanism and economic impacts of including WPPs as ramp capacity providers. To conduct the analyses, a two-stage stochastic real-time unit commitment model considering ramp capacity adequacy is formulated. Case studies indicate that both the system and the WPPs can benefit in the proposed framework.