Development and Release of the Open-source Wave Climate Environment Assessment Tool Snl-swan

INTRODUCTION Accurately assessing potential far-field environmental impacts due to wave energy converter (WEC) arrays is needed for commercialization of wave energy. One of the barriers to development is how to assess environmental concerns related to the potential effects these arrays will have on the nearand farfield wave climate. In order for projects in the United States to be approved, regulatory agencies must perform an Environmental Assessment proving little to no environmental impact. However, little is known about the environmental impacts of such wave farms as utility-scale WEC arrays have not yet made it to the market. As a result, the environmental impacts of wave farms are largely determined by numerical wave models capable of modeling large areas (i.e., spectral wave models). Therefore a validated, publicly available wave model that accurately predicts the effects due to WEC-arrays is crucial to WEC commercialization Existing spectral wave models are limited in their ability to model WECs. They typically model WECs as obstacles with a constant amount of energy absorption across all frequencies. This approach does not accurately account for the WEC’s performance, which is often tuned maximize energy capture for certain periods or sea states. Sandia National Laboratories has modified the open source spectral wave model Simulation WAves Nearshore [1] (SWAN), to include a validated WEC Module that more realistically models the frequency and sea state dependent energy absorption of WECs. SNL-SWAN is an open source code available for download and use by developers, licensing agencies, and other interested parties. This extended abstract will provide an update on code developments since the initial release of SNL-SWAN v1.0 in Oct, 2014. It will focus on the new model features and modifications that are incorporated in SNL-SWAN v1.1 (planned to be released Fall 2015). The significant modifications for SNL-SWAN Version 1.1 include the following:  An output file for power absorbed by each WEC obstacle  Directional dependent WEC power extraction  Incorporation of a frequency dependent reflection coefficient term  An update to transmission coefficients determined by WEC power matrix