In fulfilling its jurisdictional responsibilities under the Energy Policy Act of 2005 (EPAct), the Outer Continental Shelf Lands Act and the National Environmental Policy Act, the Department of the Interior’s Bureau of Ocean Energy Management (BOEM) is actively involved in evaluating environmental impacts related to the development and operation of offshore renewable energy. BOEM continues to develop best management practices (BMPs) and guidelines for monitoring and mitigation of conflicts and impacts related to construction and operations of renewable energy development on the Outer Continental Shelf (OCS). The lighting of offshore wind facilities is a primary concern for avian resources, important for aviation and navigational safety, and also of concern for visual impacts to onshore areas adjacent to renewable energy development. Earlier research on many of the issues pertaining to offshore lighting was initiated by BOEM in 2012 and resulted in the OCS Study BOEM Report 20130116 Evaluation of Lighting Schemes for Offshore Wind Facilities and Impacts to Local Environment (OCS Study 2013-0116). While the Federal Aviation Administration (FAA) has jurisdiction over how wind turbines should be marked and lit in order to maintain safe airspace for pilots, their jurisdiction applies only out to the 12 Nautical Mile (NM) limit of the territorial sea. BOEM has issued a number of commercial leases for renewable energy development for submerged lands on the OCS that extend beyond 12 NM from shore, and has jurisdiction for the development of those areas, including the marking and lighting of proposed wind turbine structures located beyond 12 NM from shore. With no wind turbines currently installed beyond 12 NM, BOEM at this time has the opportunity to evaluate whether to adopt the FAA Guidance (Advisory Circular 70/7460-1L) for installations beyond 12 NM, or to develop their own alternative guidance that could reduce or avoid impacts to birds and/or to visual onshore receptors while still maintaining pilot safety in an area with significantly less low-level aviation activity then areas closer to shore. In their efforts to provide clarity, direction, and standardization to the offshore wind industry in advance of the first turbines being installed beyond 12 NM, BOEM has contracted with ESS Group Inc. (ESS) to evaluate the adoption of FAA guidance beyond 12 NM, and to propose alternative guidance that would address aviation safety and environmental concerns including effects on birds and visual impacts to shoreline users. ESS, supported by teaming partner Garrad Hassan America (DNV GL), evaluated the FAA guidance for marking and lighting wind turbines and conducted additional research on other available lighting guidance, offshore lighting impacts to birds, visual impacts, and technical capabilities of various lighting and control technologies in order to help inform the preparation of alternative guidance. The draft alternative guidance is presented as Appendix A of this report. This report will provide an overview of the research conducted and the findings used to justify the alternative guidance presented in Appendix A.