| Description: |
Climate change is impacting people, industries and economies to ever greater degrees. One of the rapidly growing industries impacted by climate change is offshore wind energy. Numerous studies have shown a wide range of climate change impacts on the offshore wind resource. However, other potential impacts of climate change are less understood. This thesis investigated climate change impacts on installation and maintenance of offshore wind farms. Installation and maintenance each account for 20-25% of offshore wind farm lifecycle costs, and these activities significantly depend on ocean wave conditions. Wave reanalysis datasets, like ERA5, are often used to assess long-term wave climate. This thesis assessed the accuracy of the ERA5 wave dataset as a source of global ground-truth significant wave height data. The author showed that ERA5 tends to underestimate significant wave height above 5 m. The ERA5 accuracy increases with the increasing distance to shore, and is higher in more recent years. These findings informed the use of the ERA5 wave data in combination with atmospheric data from eight CMIP6 climate models to train a neural network to produce wave climate projections. The large size of the dataset, which included global 3-hour data for five variables (including significant wave height), hindered learning of the feed-forward neural network. Since the neural network failed to produce acceptable wave climate projections, an ensemble of existing numerical projections was used to quantify impacts of climate change on accessibility - the fraction of time when the weather does not impede installation and maintenance of offshore structures. This ensemble consisted of 11 wave simulations from the COWCLIP project, where wave models were forced with atmospheric data from seven CMIP5 climate models. This study found that accessibility is projected to increase in the North Atlantic and Asia, but decrease in Central America and in some cases in Australia and on the western North American coast. Most of the ... |