An Offshore Wind Energy Geographic Information System (OWE-GIS) has been developed for the purpose of assessing the economically accessible offshore wind energy resource for the United Kingdom. The UK OWE-GIS estimates the costs of energy from an offshore wind farm taking account of the major capital components; development costs dependent on water depth and distance from nearest ports or grid connection points; the potential energy production dependent on annual average wind speed, potential array losses, and turbine availability; operations and maintenance costs; and financial parameters such as discount rate and project lifetime. A sensitivity analysis is presented to show the influence of discount rate, project lifetime, and assumptions about overall capital expenditure (CAPEX), availability, and annual mean wind speed. (C) 2015 Published by Elsevier Ltd.