Abstract
Wave energy device availability, defined as the proportion of time a device is fully operational and capable of generating energy, depends on the reliability of device components and the downtime between component failure and repair. The time to repair depends on several factors, including potential waiting times for an extended period of benign metocean conditions to allow device access and maintenance activities to proceed. In this study, a weather window analysis is conducted for two candidate sites identified for potential deployment of the Wavepiston wave energy converter using ocean climate reanalysis data. The weather window analysis focuses on how waiting times between weather windows and site accessibility vary with operating thresholds for operations and maintenance (O&M) vessels, e.g significant wave height limits, and minimum weather window durations. In addition to exploring seasonal variations in waiting times and access levels, the effect of daylight-hour restrictions on maintenance activities is also considered. Furthermore, the impact of waiting times and access levels, as proxies for time to repair, on device availability is assessed using a Monte Carlo simulation based on nominal device reliability. The availability study demonstrates how uncertainty in waiting times and access can be propagated into estimates of device downtime and availability, thus providing a more complete picture of the impact of O&M strategies, e.g. daylight only restrictions on maintenance, on energy generation potential.