Tethys is an online knowledge management system that provides the marine renewable energy (MRE) and wind energy communities with access to information and scientific literature on the environmental effects of devices.[1] Named after the Greek titaness of the sea, the goal of the Tethys database is to promote environmental stewardship and the advancement of the wind and marine renewable energy communities. The website has been developed by the Pacific Northwest National Laboratory (PNNL) in support of the U.S. Department of Energy (DOE) Water Power Technologies Office and Wind Energy Technologies Office.[2][3] Tethys hosts information and activities associated with two international collaborations known as OES-Environmental and WREN, formed to examine the environmental effects of marine renewable energy projects and wind energy projects, respectively.