The rapid growth of renewable energy (RE) is disrupting and transforming the global energy system, especially the electricity industry. As a result, supporters of the politically powerful incumbent industries and others are critiquing the feasibility of large-scale electricity generating systems based predominantly on RE. Part of this opposition is manifest in the publication of incorrect myths about renewable electricity (RElec) in scholarly journals, popular articles, media, websites, blogs and statements by politicians. The aim of the present article is to use current scientific and engineering theory and practice to refute the principal myths. It does this by showing that large-scale electricity systems that are 100% renewable (100RElec), including those whose renewable sources are predominantly variable (e.g. wind and solar PV), can be readily designed to meet the key requirements of reliability, security and affordability. It also argues that transition to 100RElec could occur much more rapidly than suggested by historical energy transitions. It finds that the main critiques published in scholarly articles and books contain factual errors, questionable assumptions, important omissions, internal inconsistencies, exaggerations of limitations and irrelevant arguments. Some widely publicised critiques select criteria that are inappropriate and/or irrelevant to the assessment of energy technologies, ignore studies whose results contradict arguments in the critiques, and fail to assess the sum total of knowledge provided collectively by the published studies on 100RElec, but instead demand that each individual study address all the critiques’ inappropriate criteria. We find that the principal barriers to 100RElec are neither technological nor economic, but instead are primarily political, institutional and cultural.