This paper assesses the impact of inter-annual resource data variability on the techno-economic performance assessment of the WaveStar and Pelamis P1 wave energy devices. Accessing sufficient quantity of resource data has always been a problem for techno-economic studies. Often studies have only one year of wave energy data available. Recent studies have indicated that the variability of resource climate for a location can change inter-annually as well as inter-decade. The alteration in wave energy available will naturally have a significant impact on financial performance of the device and its profit in wave farms. This paper used an extensive library of 16 years consecutive modelled wave energy data for the Belmullet test site off the west coast of Ireland. A full analysis of the variation in energy outputs for the WaveStar and the Pelamis P1 is presented as well as a financial analysis reporting on cost of electricity, net present value and internal rate of return for the device. Finally, the paper examined the impact of using individual yearly energy output values in the cash flow analysis instead of the normal method of using one average value, as well as moving average impacts.
