Amory Lovins claims that rather than supporting distressed nuclear plants, greater overall carbon savings could be had by allowing them to close and funding low-cost efficiency improvements instead (“Do Coal and Nuclear Generation Deserve Above-Market Prices?,” The Electricity Journal, July 2017). He errs in presenting the issue as a dichotomous choice in which we can either support nuclear plants or support efficiency, but not both. The magnitude of the decarbonization challenge means that many resource types, including both nuclear and efficiency, will be needed. Replacing nuclear plants with efficiency would require very large additional efficiency improvements on top of the significant progress that will occur in any case, pushing into a realm where the marginal efficiency opportunities are likely to have decreasing availability and increasing cost. Since any replacement could not be immediate, carbon emissions would increase substantially in the near term.