Wave energy converters should be actively controlled to ensure maximum energy extraction from waves. However, it is important that the control objective is correctly posed, so that the control effort is directed towards economically advantageous actions.

The objective of this document is to set the context for the parametric structure of the performance function (PF) which will be used within WP5 of the LiftWEC project. Ideally, the performance structure will be based on a bulk economic performance indicator, such as Levelised Cost of Energy (LCoE) and that that performance indicator be expressible as a function of the control actions, so that the control actions can be optimised, maximising the economic performance of the LiftWEC. This ideal presents two difficulties: LCoE is very difficult to enumerate, especially with regard to operational costs, and it is virtually impossible to propagate the effect of control actions all the way through to LCoE. Therefore, this document will articulate the components which make up an idealised PF and examine the extent to which such components can be represented as functions of the control inputs.

In addition, the extent to which disparate performance function components (e.g. cost, power production) can be combined into a single monolithic PF is examined, opening the possibility for multi-criteria optimisation techniques in the determination of the optimal control signals.