IEC TS 62600-101:2015(E) establishes a system for estimating, analysing and reporting the wave energy resource at sites potentially suitable for the installation of Wave Energy Converters (WECs). This Technical Specification is to be applied at all stages of site assessment from initial investigations to detailed project design. In conjunction with IEC TS 62600-100 (WEC performance) it enables an estimate of the annual energy production of a WEC or WEC array to be calculated.