A Wider Horizon

U.S. energy system investment during the next 40 years is likely to exceed US S3 trillion plus the cost of transportation-related electrification. The magnitude of this cost and its importance to economic competitiveness and to climate change mitigation create the need for highly robust, rigorous, and informative energy system planning processes. We see a great need for new tools, an area that will require significant investment in associated research and development. Finally, we highlight the large amount of recent activity in the United States at the state and federal levels in regard to crafting production tax credits, investment tax credits, and renewable portfolio standards; future policies might also include emissions taxes or cap-and-trade mechanisms. Although such policies are intended to move society from a less desirable equilibrium to a more desirable one according to some particular set of criteria, the complexities of the energy systems they intend to influence make their actual effects unknown, and there are potential negative effects and unde sirable interactions with competing policies. Policy design and evaluation tools are needed to more completely assess and understand the full impacts of these complex issues. New analytic tools must be developed to accomplish this goal.