Optimizing Offshore Wind Integration through Multi-Terminal DC Grids: A Market-Based OPF Framework for the North Sea Interconnectors
Bernardo Castro Valerio, Vinícius Albernaz Lacerda, Marc Cheah-Mañe, Pieter Gebraad, Oriol Gomis-Bellmunt
TL;DR
This work addresses offshore wind integration in a multi-terminal HVDC grid by developing a market-based non-linear AC/DC OPF that explicitly models inter-zone exchanges and price-zone constraints. The methodology ties day-ahead market pricing, a quadratic generation cost CG(P_N) with price $\rho=2\alpha P_N+\beta$, and an AC/DC OPF that includes curtailment and inter-zone limits, enabling realistic simulations of price-maker versus price-taker dynamics. The North Sea case demonstrates how price-zone constraints and wind availability influence prices, curtailment, and inter-zone power flows, highlighting that PN-based constraints alone are insufficient and must be complemented by price-cost relationships. The approach offers a pathway to more accurate planning and operation of hybrid AC/DC grids and can inform transmission expansion decisions in offshore wind hubs. The results underscore the practical impact of integrating market dynamics into grid optimization for offshore wind-rich regions.
Abstract
Interconnecting price zones and remote renewable energy sources has emerged as a key solution to achieving climate goals. The objective of this work is to present a formulation that extends the base optimal power flow model with price zones constraints to forecast the operations of upcoming offshore wind developments integrated into a multi-terminal DC grid. A case study based on the 2030 development of the North Sea is used to exemplify the utilization of the formulation. Here, three cases are presented, one with the price as a parameter and the other two with the price as a variable dependent on power flows between price zones. The paper demonstrates that, for large power flows, it is necessary to include additional constraints beyond line limitations to accurately capture the effects of price zone exchanges.