The marine renewable industry is primarily focussed on delivering electrical energy at a utility scale from waves and tides. Energy production estimates (EPEs) for projects require associated confidence levels, in order for banks and management boards to arrive at financial close and to allow project construction to commence. This paper considers confidence levels in wind energy project EPEs, and explores how they may be applied to marine energy projects. Confidence in a marine energy EPE is essentially a measure of resource and energy loss uncertainties associated with this EPE. A framework for categorising uncertainties is applied and these categories are discussed qualitatively, with a grading of various uncertainties in order of significance. The P90/P50 ratio in a marine EPE is related to overall uncertainty, and an upper bound is derived for this overall EPE uncertainty for initial assessments of commercial marine energy projects.
