Submission 306
Cost Surfaces for Joint Export-Technology and Substation-Position Decisions in Offshore Wind
57 GIW26-306
Presented by: Stephen Hardy
Enersynt BV. Geldenaaksevest 2, 3000 Leuven, Belgium., Belgium
The techno-economics of the inter-array and export system of an offshore wind power plant carry several coupled decisions: the collection voltage, the export technology, and the offshore substation (OSS) position. Typically, industry takes them in sequence, comparing technologies at a few fixed OSS positions near the array centroid. Yet the OSS optimum sits where two opposing forces balance, and their strengths depend on the choices being compared. The export pull towards the point of common coupling is strong and stepped for HVAC, as reactive charging current claims ampacity, but weak for HVDC, which carries none. The inter-array pull towards the centroid is strong at 66 kV and eases at 132 kV. On a 2.1 GW test case, we evaluate the complete design over a surface of candidate OSS positions, for HVAC and HVDC at 66 and 132 kV. We show the optima do not coincide, and within the single concession the cheaper technology and the preferred collection voltage flip with OSS position. With hundreds of millions of euros at stake, the entire concession, not a few points, should be evaluated. Optimisation software makes this routine, and with 132 kV collection arriving, the time to make it standard practice is now.