Strategically estimated CapEx: wave energy converter costs breakdown and parameterisation

Abstract

Abstract In wave renewable energy, the Capital Expenditure (CapEx) is often a fixed number or depends on a single variable (e.g. power or converter characteristic mass). Hence, it poorly highlights the CapEx dependency on the Wave Energy Converter (WEC) and Wave Energy Farm (WEF) design, which in turn depend on the site characteristics. As, most of CapEx components are accessible by wave companies nowadays, this article introduces the new generic CapEx method. This method is divided into three steps: (1) distinguishing WEC’s elements from the WEF’s; (2) defining the parameters characterising the WECs, WEFs, and site locations; and (3) estimating elements that affect WEC and WEF elements’ cost and translate them into factors using the parameters defined in step (2). The case study is based on Wavepiston because of its advanced stage and the availability of its WEC information and costs. The focus of this study is on the detailed application of step (1) and (2) to Wavepiston, to estimate the Wavepiston WEC cost using step (3). This study also illustrates how to handle complex and limited datasets of WEC configuration and site characteristics. Moreover, the results from the CapEx method were validated by manual estimations from Wavepiston. It was found for Wavepiston WEC, the site characteristics were the least affecting parameters in comparison to the WEC configuration parameters. This study also applies another parameterised cost calculation method based on the Froude law similitude as a simpler but more rigid alternative, for the CapEx method. It was shown that with appropriate scaling parameter, the Similitude method provided similar, although higher, estimations than the CapEx method’s within low ranges of WEC up-scaling. In high ranges of up-scaling, the Similitude method overestimated Wavepiston WEC cost.