The objective of this rebuttal letter is to provide a critical analysis of the article entitled "Spatial planning to estimate the offshore wind energy potential in coastal regions and islands. Practical case: The Canary Islands" [Energy 143 (2018) 91-103], mainly in relation to its methodology, suitable marine areas and electricity production costs. The absence of basic considerations about the characteristics of the insular power grids, the composition of the electricity costs in the Canary Islands, and the lack of rigor in some assumptions related to visibility constraints, offshore costs, integration costs, the mixing of data from different time periods and the references used, provides unrealistic and useless results for a necessary debate about the potential of offshore wind energy in the Canary Islands. In this rebuttal letter we will also demonstrate that the potential offshore wind capacity calculated by the authors is much lower. Moreover, the assertion that the electricity cost from offshore wind calculated by the authors is lower than the current electricity cost is wrong and, in fact, the cost of electricity from offshore wind is higher in the time period when the analysis was made, and also at present. (C) 2018 Elsevier Ltd. All rights reserved.