PNNL

Abstract

This report presents a practical framework to co-design plant-level controls, storage, and market participation demonstrated for integrating large offshore wind farms to the onshore power grid. The approach links long-term sizing and scheduling decisions with fast dynamics so that reliability and economic value are improved together. We formulate multi-scale multi-stage stochastic optimization models to coordinate wind output, battery operation, and reserve policies under uncertainty. To verify dynamic performance, we conduct detailed time-domain simulations on a reduced Western Interconnection model. The study compares two operating modes: conventional maximum power point tracking and a de-loaded strategy that intentionally holds headroom for frequency support. Results show that the co-designed operating point closely matches steady-state targets before the event, maintains stability after the trip, and delivers a higher quality frequency response than purely maximizing energy. The de-loaded policy reduces the lowest frequency dip and moderates power ramp rates while preserving sufficient energy for recovery. On the market side, the framework highlights how coordinated bidding and storage dispatch can enhance revenues and mitigate risks in day-ahead and balancing markets, while accounting for battery wear. Overall, the report demonstrates an end-to-end methodology that connects design, control, markets, and grid code validation. It provides actionable guidance on selecting reserve levels, tuning supervisory controllers, and sizing storage to support dependable, profitable offshore wind integration. The workflow uses open-source modeling tools and scenario-based uncertainty representations, and is adaptable to hybrid plants. Findings inform planners, operators, and regulators seeking to balance performance, compliance, and cost effectively.