As the wave and tidal industries mature and commercial scale projects reach the point of financial investment decision (FID), it is important that energy yield and uncertainty assessments are presented clearly and consistently to all parties involved.
It is likely that for each wave or tidal energy project reaching FID, more than one energy yield and uncertainty assessment will be prepared. Given the range of methodologies available for both wave and tidal, assessments for a single project may have material differences. These may include assumptions regarding technical losses used to derive net energy generation from gross energy generation. When both the definition of a loss and the value of the loss differ, direct comparisons are difficult to make. Compounding this challenge may be the use of different uncertainty categories and their definitions, making it difficult to interpret and compare the results of different reports at the various probability levels (P90, P95, etc.).
Energy yield and uncertainty assessment methodologies in wave and tidal are distinct in a number of ways; however, they do share a similar same fundamental approach. Both derive gross generation from a site’s long term resource and a marine energy convertor’s power performance data. Technical loss factors are then applied to derive expected net energy generation. An uncertainty analysis is then conducted to determine the probability distribution of net energy production.
However, without standard definitions for such loss factors and uncertainty categories, there is a risk that it will be difficult to compare studies prepared by different developers and consultants, even when using the same fundamental assessment methodologies. Standardised definitions are therefore proposed to facilitate direct comparison among different studies. In addition, these will lead to more productive dialogue and ultimately improved understanding of technical losses and uncertainties.
This document has been developed in collaboration with a wide range of industry stakeholders. These include independent consultancies, technology developers and project developers.