This report articulates nine mechanisms by which the smart grid can reduce energy use and carbon impacts associated with electricity generation and delivery. The quantitative estimates of potential reductions in electricity sector energy and associated CO 2 emissions presented are based on a survey of published results and simple analyses. This report does not attempt to justify the cost effectiveness of the smart grid, which to date has been based primarily upon the twin pillars of cost-effective operation and improved reliability. Rather, it attempts to quantify the additional energy and CO 2 emission benefits inherent in the smart grid's potential contribution to the nation's goal of mitigating climate change by reducing the carbon footprint of the electric power system. v SummaryThis report provides an assessment of nine mechanisms by which the smart grid can reduce energy use and carbon impacts associated with electricity generation and delivery. To the extent possible, the associated reductions in electricity and CO 2 emissions were quantified to illustrate the benefits inherent in the smart grid's potential contribution to the nation's goal of mitigating climate change from reducing the carbon footprint of the electric power system. Environmental impacts to air and water quality and land use were not considered, nor were impacts on end users that rely upon natural gas as their energy source.The reductions in electric utility electricity and CO 2 emissions in 2030 attributable to the nine mechanisms by direct and indirect effect are shown in Table S.1. The direct reductions were calculated for the mechanisms that affected electricity and CO 2 emissions directly through implementation of the smart grid technologies. Indirect reductions are derived by translating the estimated cost savings in energy and/or capacity into their energy and carbon equivalents through purchase of additional costeffective energy efficiency. This can represent a policy decision to reinvest the savings to purchase additional more cost effective energy efficiency and renewable resources. (a) Assumes 100% penetration of the smart grid technologies.The estimates in Table S.1 are based on the annual electricity supplied to the U.S. grid and the associated CO 2 emissions in 2030, as forecast by the U.S. Energy Information Agency. They represent the percentage reduction in the annual U.S. electrical energy production and resulting CO 2 reductions, based on the emissions of average U.S. generating power plant. This allows the percentage reductions to be placed in context with RPSs for their electric system that have been already adopted by many states, typically 20% or more over a period of one or two decades. viThe uncertainties in these estimates are relatively high, based on the range of estimates provided by the studies drawn upon for this report, and the judgment of the authors. While the individual reduction estimates are typically judged to be uncertain in a range of ±50%, and in some cases larger, the variety inherent in t...