Posters

Abstract

As sites are maturing there is an expected increase in operational expenditure (OpEx) due to the aging of assets and, as a result, an increase in major repairs and replacements requiring high-cost specialist vessels. This is then combined with the reality of post-subsidy operation. A shift to the energy market makes sites more vulnerable to curtailment and negative pricing periods. A decrease in income combined with an expected increase in O&M repair costs and expected prolonged periods of curtailment drives the need for an efficient and, most importantly, cost effective maintenance strategy. One such strategy, which has been gaining traction in recent years, is opportunistic maintenance (OM). It was found that the general definition of OM within the literature could be defined as “performing maintenance activities during periods of corrective maintenance and/or during periods of low production/wind speed”. This work provides an overview of existing maintenance strategies used within offshore wind including corrective, condition based, and preventive maintenance. A literature review was then conducted for OM focused specifically on offshore wind turbines. Based on the findings, a new proposed framework has been created to include the threat of negative pricing and curtailment. These market constraints present additional “opportunities” to perform scheduled maintenance activities. This has led to the proposal of the OM+ strategy. This strategy has been developed to contain the existing elements of OM, with the addition of “market” maintenance opportunities. Case studies using the US market show that these factors are likely to lead to a decrease in OpEx due to capitalising on “free” downtime. In addition to the OM+ process, this work also suggests a new definition for recording and reporting availability – moving from time/energy-based availability to market-based availability.