Emissions Impacts and Benefits of Plug-In Hybrid Electric Vehicles and Vehicle-to-Grid Services

Abstract

Plug-in hybrid electric vehicles (PHEVs) have been promoted as a potential technology to reduce emissions of greenhouse gases and other pollutants by using electricity instead of petroleum, and byimproving electric system efficiency by providing vehicle-to-grid (V2G) services. We use an electric power system model to explicitly evaluate the change in generator dispatches resulting from PHEV deployment in the Texas grid, and apply fixed and non-parametric estimates of generator emissions rates, to estimate the resulting changes in generation emissions. We find that by using the flexibility of when vehicles may be charged, generator efficiency can be increased substantially. By changing generator dispatch, a PHEVfleet of up to 15% of light-duty vehicles can actually decrease net generator NOx emissions during the ozone season, despite the additional charging load. By adding V2G services, such as spinning reserves and energy storage, CO2, SO2, and NOx emissions can be reduced even further.

Electric vehicles in imperfect electricity markets: The case of Germany

“…Andersson et al (2010) find that providing regulating power with PIEV fleets in Germany and Sweden may be an economically viable strategy. Sioshansi and Denholm (2009) demonstrate that the provision of spinning reserves by electric vehicles could increase the efficiency of thermal electricity generation, which in turn decreases emissions. In a more general analysis, Sioshansi and Denholm (2010) analyze the value of plug-in hybrid electric vehicles as flexible grid resources, considering unit commitment and ramping constraints.…”

A spatially and temporally resolved model of the electricity grid – Economic vs environmental dispatch

“…While other dispatch models have been developed, the results are not spatially resolved and thus do not count for transmission constraints [53][54][55]. Very few studies are spatially resolved and amenable to air quality analyses [5,44,51].…”

Emissions impacts of plug-in hybrid electric vehicle deployment on the U.S. western grid

“…A number of existing studies have found that plug-in hybrid electric vehicles (PHEVs) have emissions benefits over hybrid electric vehicles (HEV) and conventional vehicles even when accounting for grid emissions [1][2][3][4]. It has also been shown that the charge requirements of a conversion of a large portion of existing light duty auto fleets to PHEVs can be supported by existing grid infrastructure with minimal increases in annual energy demand [2,[5][6][7][8].…”

“…One of the most important conclusions from prior studies is that emissions impacts of PHEVs are sensitive to the generation mix of a particular region [3,5]. While included as part of a previous study estimating percentages of light duty vehicle stock that could be supported by existing infrastructure in sub regions of the U.S. power grid [7], California has yet to be the subject of a comprehensive and detailed grid impact analysis covering emissions, operations, and the integration of a PHEV future.…”

“…Prior grid scenario analyses and PHEVgrid interaction studies have used either grid models based on least cost unit commitment [2,3,9], the assumption that vehicle charging is provided by a single electricity generator technology [4], or an average regional or national grid mix [3,6,7,10,11]. The methodology presented herein is based on a correlation between system load and resource capacity factors identified in historical data that capture the complexity of resource dispatch without consideration of price signals, markets, and regulations that exist in the real system.…”