This research paper explores energy transition impacts on competitive power markets, finding every U.S. organized power market except ERCOT is oversupplied due to seven oversupply drivers. Oversupply slows decarbonization, but market operators and load serving entities have options to responsibly manage the power system through this transition. The full version of this paper was published in the March 2019 issue of Current Sustainable/Renewable Energy Reports, and is available upon request.