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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...

Replacing a significant portion of the nation's light vehicle fleet with plug-in hybrid electric vehicles (PHEVs) offers the potential of reducing our dependence on petroleum fuels together with important economic and environmental benefits. The electric power grid is built to support peak loads and, as a consequence, suffers from low asset utilization rates in off-peak periods. In principle, this under-utilized capacity could effectively power a national fleet of PHEVs with little need to increase the energy delivery capacity of the existing grid infrastructure. In practice, this ideal opportunity may be compromised by several factors including the size and distribution of the PHEV fleet, and the timing of vehicle charging activity. This report documents work conducted by Pacific Northwest National Laboratory (PNNL) for the Department of Energy (DOE) to address three basic questions concerning how typical existing electrical distribution systems would be impacted by the addition of PHEVs to residential loads. These questions are:  How many vehicles could the existing power delivery system support in the near future?  What time of day would PHEVs be charged?  Where would the vehicles be charged? The present study complements other research being performed for the DOE by the University of Michigan (UM) in collaboration with PNNL on various issues relating PHEV adoption and marketability. The primary focus of this study was to estimate impacts of PHEV charging on the components of residential feeders. The first part of the analysis was designed to study PHEV charging impacts on the distribution system as a whole. A load flow study was performed for various PHEV penetrations to observe whether any principal components of main feeders exceed their capacity because of PHEV charging. The second part of the analysis focused on the potential impact of the additional load on the distribution transformers serving each individual residence. In both parts of the study computerized modeling of feeder-level load flow compared the existing loading profile and component-specific loads with those created by the superimposition of a hypothetical PHEV load distribution. Three electric utilities: Franklin PUD, Snohomish PUD and Puget Sound Energy (PSE) collaborated with this study by providing information that allowed system-specific feeder modeling. A principal conclusion drawn from this study is that the addition of PHEV load at an individual residence may or may not have noticeable impacts on the existing distribution system depending on the overall penetration level and charging strategy used. The distribution utility's system planning philosophy used to size distribution transformers and the backbone feeder system also plays a large part in determining whether or not, or when in the future, additional PHEV load would impact the system. Acronyms EV electric vehicle PHEV plug-in hybrid electric vehicle LDV light-duty vehicles

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...