Establishing 100 % clean electricity goals is currently in vogue.11The term “clean” energy includes all resources that do not emit greenhouse gases (GHG). To-date in the United States (US), 19 large utilities, nearly 210 cities, and 150 corporations have established such an ambitious target.22S. Ptacek with A. Levin, “Race to 100% Clean”, Natural Resources Defense Council (NRDC), December 2, 2020, available at:https://www.nrdc.org/resources/race-100-clean. The authors are very supportive of the concept for addressing climate change. But with possibly only a few unique exceptions of which the authors are not aware, such a goal is currently physically and economically impossible unless certain policies and practices are changed.The term “Useful” clean energy refers to that amount of hourly clean energy supply that matches hourly customer electric load. In that regard, electric utility planners seeking 100 % clean energy are between a proverbial rock and a hard place. The rock is the fact that renewable energy is intermittent and non-dispatchable. The hard place is customer load, which, but for marginal adjustments with utility demand management, happens when customers want it to happen. Neither are sufficiently controllable by the utility to assure that supply exactly meets demand as required.Every utility has a hypothetical “inflection point” where increasing high levels of renewables begin to exceed hourly load and must be turned down or otherwise curtailed. Doing this wastes renewables investment. Further increases in renewable energy installations within or near the utility, whether grid-level or distributed, only increase this mismatch. As a result, diminishing returns for Useful energy increase as renewables increase.This article provides examples for four electric utilities in the Midcontinent Independent System Operator (MISO) market. All of them have inflection points. All of them would “stall out” in Useful energy when renewable energy reach levels at about 60 %–80 % of their annual load (equivalent to a Renewable Energy Standard (RES) or Renewable Portfolio Standard (RPS)).The cost of attaining levels of renewable energy higher than the “inflection point” gets very expensive for the utility retail customers as more local renewables are added. In addition to illustrating the issue, the authors propose potential solutions.