Models of the U.S. electricity sector are relied upon by sector stakeholders and decision makers, but the recent surge in variable renewable energy (VRE), such as wind and solar, led a team of modeling experts to examine how these models would represent scenarios with high penetrations of VRE. Four agencies, including the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), hosted two workshops that led to a new report where the teams identified areas of importance for modeling VRE, performed experiments to determine key assumptions, and compiled a set of recommendations for future research in this area.