Posters

Abstract

Pre-construction (AEP) assessments remain a cornerstone of offshore wind project development, financing, and bankability. However, growing evidence from recent projects in the Baltic–Nordic region indicates a persistent gap between predicted and realized AEP, particularly for large-scale offshore wind farms being developed in cold-climate conditions. While current AEP validation frameworks focus primarily on wind resource assessment, wake effects, and turbine performance, they often lacs the importance of installation logistics, port infrastructure readiness, and seasonal constraints on commissioning timelines and early operational output. Paper presents how port infrastructure limitations and installation logistics directly affect realized AEP outcomes, and how these effects can be identified and mitigated at pre-construction stage. Analysis is based on a mixed-method PhD study combining a technical survey of 17 offshore wind developers active in the Baltic–Nordic region, quantitative engineering assessment of turbine and foundation dimensions, weights, and port handling requirements, and a detailed case study of a cold-climate industrial port preparing for offshore wind marshalling operations in Raahe FI. Survey results show that developers are planning (2025-2036) offshore wind projects with capacities from 700 MW to 9 GW, using next-generation turbines of 15–25 MW class. Turbines feature rotor diameters of 230-305 m, hub heights up to 185 m above sea level, and foundation types, including monopiles, jackets, and gravity-based foundations, reaching weights up to 7,500 tones. Engineering analysis shows that such scale-up imposes requirements on marshalling ports, including ground bearing capacities ≥40 t/m², water depths ≥10–14 m, heavy-lift cranes exceeding 1,000 tones, and laydown areas 25 ha per GW installed. Research finds that insufficient port readiness and constrained installation windows, particularly in ice-affected regions where offshore operations are effectively limited to the May–September period, can delay installation and commissioning by several months. These constraints are further reinforced in the Baltic Sea, which functions as a semi-enclosed sea with limited access routes, draft restrictions, and seasonal ice conditions for vessels, making offshore installation planning significantly more time and cost-sensitive than in open-ocean regions. Such delays shift early production into periods with less favorable wind conditions, alter expected seasonal energy output profiles, and lead to discrepancies between predicted and actual AEP. These deviations are typically directed to turbine underperformance, however, they primarily result from infrastructure and installation constraints that fall outside the scope of conventional pre-construction AEP models. Paper presents that improving AEP validation requires extending the system boundary beyond turbine and wind resource modelling to include logistics-adjusted commissioning timelines and port capability indicators. Based on survey evidence and engineering calculations, it proposes a set of port readiness and installation logistics parameters, such as: ground-bearing capacity, storage availability, heavy-lift feasibility, seasonal timing, and the implementation of green operations and electrification, as inputs for refining pre-construction AEP assumptions. It underlines importance of early-stage cooperation between authorities, developers, ports, and service providers, helping infrastructure investments and logistical planning to be aligned with project-specific AEP expectations. By integrating port readiness into AEP validation, developers can reduce forecast uncertainty, improve risk allocation, and achieve more realistic performance results.