Maximising value of electrical networks for wave energy converter arrays

Abstract

Currently there are the beginnings of a commercial wave energy industry and the ultimate ambition will be to deploy wave energy converters (WECs) in arrays, or wave farms, in a similar fashion to offshore wind. These arrays will require electrical networks to collect and export the generated electrical power to shore and onto the electrical grid. For large scale wind farms the inter-array and export electrical networks can represent more than 20% of the project’s capital expenditure. Submarine power cables account for a large proportion of this cost. This cost proportion is expected to be the same for WEC arrays.This paper investigates strategies to reduce the cost of WEC array electrical networks by maximising the value of the network. The paper explores the possibility of underrating and dynamically rating the electrical array and export cable systems for WEC arrays in order to assess the cost savings that can be made. This paper will also look at a simulated WEC array power output time series. The aim is to establish whether the electrical equipment, particularly submarine cables, will operate outside its design parameters if under-rated based on maximum continuous current. This paper also investigates the WEC capacity factor effect on the overall economics of the array electrical system.It is concluded that cost savings could be made in the electrical network by utilising one, or a combination of, the outlined strategies. Understanding the potential benefits and applications of these strategies will assist in delivering cost effective WEC arrays in the future.