When the committee examined prior attempts to project even simple things like total demand, it found that most estimates had missed the mark. For this reason, it did not try to predict what the system will look like several decades in the future. Instead, the committee identified a number of driving forces— social, technical, economic—that are likely to alter the landscape of the U.S. power system. These include the following: 1. Possible large growth in future demand for electricity. 2. Efforts to decarbonize the U.S. economy, and eliminate the emission of conventional pollutants, both by transitioning power generation to low or zero-emission sources and by making much greater use of decarbonized electricity as a substitute for fossil fuels in transportation, buildings and industry. 3. Developments at the edge of the grid such as distributed generation, storage, microgrids, energymanagement resources, and energy efficiency measures. 4. Grid stability challenges arising as a result of high penetrations of nondispatchable sources of generation such as wind and solar. 5. A desire to reduce social inequities. 6. Concerns about the impacts of the energy transition on employment. 7. A changing international environment including powerful market forces arising from globalization, shifts in the locus of electricity-relevant innovation, and growing concerns about state-sponsored competition and disruption.