Although substantial progress has been made in understanding the environmental impacts of electric vehicles (EVs) under deep deployment scenarios, there remain major gaps in our knowledge. In future scenarios where EVs demand a double-digit share of available electric power, marginal CO2 intensity during (off-peak) EV charging times will typically be higher than annual average CO2 rates from the bulk power grid, upon which many current studies base their projections. The NCST EVALUATE (Electric Vehicle Assessment and Leveraging of Unified models toward AbatemenT of Emissions) project (Phase I) has explored this risk of diminishing returns and developed a series of tools to evaluate future marginal (i.e., next increment) CO2 intensity in the Southeast U.S. as a function of both season and time-of-day. This modeling capability offers the potential for decision makers and system operators to create a kind of “Goldilocks” condition for intermediate term EV deployment. That is, to take advantage of excess capacity at low CO2 intensity while avoiding EV charging at times of high marginal emissions. Phase II focuses on: 1) a case study using these tools to determine the location/characteristics of EV charging devices (i.e., Level 2 and 3 EVSEs) within an urban area (Atlanta, GA) to optimize EV charging while minimizing marginal emissions; 2) developing guidance and tools to assist others in adapting these tools to other regions; 3) technology transfer activities to get these NCST developed tools into the hands of practitioners and decision makers to maximize the effectiveness of public and private-investments in charging infrastructure.
