A Technology-Informed Accessibility Metric for Site Selection of Offshore Renewable Energy Systems: A Case Study in Europe

The selection of appropriate offshore renewable energy system sites is essential for their economic viability, given the uncertainties surrounding their potential. While current site selection approaches primarily focus on energy potential, the impact of operation and maintenance (O&M) factors on the site's location is also critical. Traditional accessibility assessment metrics are limited for detailed accessibility evaluations, requiring the development of a novel, technology-informed metric that considers crucial factors such as metocean conditions, visibility, system failures, and O&M logistics. For this study, data on wave heights, wind speed and fog were collected from the European Centre for Medium-Range Weather Forecasts (ECMWF) database for the years 1959 to 2021, and matched with failure rates, vessel types, required repair times and sunrise/sunset times according to predefined criteria. Available time frames were then marked and counted as accessible times. The accessibility metric is calculated as a weighted average, with weights obtained from the downtime characteristics of each O&M activity. The study conducted an accessibility analysis across five different locations in Europe, revealing that limited visibility significantly reduces accessibility, resulting in up to a 60% reduction, while sea fog has less significant impact, contributing only up to a 5% reduction. Intra-annual and inter-annual variability, as well as the impact of different visibility factors, were graphically illustrated. The study also found that accessibility is inversely proportional to energy potential in most locations. Therefore, site selection should consider both energy potential and accessibility assessments, which is feasible with the proposed technology-informed accessibility metric. The metric's specific calculation methodology and weight distribution for each factor were thoroughly explained. The study's findings highlight the importance of accounting for O&M factors and accessibility when selecting offshore renewable energy system sites. Future research should explore additional sources of data and expand the accessibility metric's application to other regions and renewable energy systems. Additionally, more research is needed to validate the proposed metric's effectiveness in guiding site selection decisions.