Optimal Predictive Maintenance Policy for an Ocean Wave Farm

Abstract

The levelized cost of electricity for wave energy converters (WECs) is high and one important way to reduce this cost is to employ strategies that minimize the cost of maintenance of WECs in a wave farm. In this paper, an optimal maintenance strategy is proposed for a group of WECs, resulting in an adaptive scheduling of the time of repair, based on the state of the entire farm. The state-based maintenance strategy seeks to find an optimal tradeoff between the moderate revenue generated from a farm with some devices being in a deteriorated or failed state, and the high repair cost that typifies ocean wave farm maintenance practices. The formulation uses a Markov decision process approach to devise an optimal policy, which is based on the count of WECs in different operational states. The effectiveness of the proposed approach is computationally demonstrated on the maintenance of an ocean farm consisting of 30 WECs.