alternating current (ac) charging, (2) fast ac charging, (3) direct current (dc) charging in homes, and (4) ultrafast dc charging. Thus, a Combined Charging System could offer a single-port fast-charging system that still enables plug-in owners with vehicles designed for Level 1 or Level 2 to recharge at public stations. The companies endorsing this system include three U.S. DRIVE members: Chrysler Group LLC, Ford Motor Company, and General Motors Company. The ACEA has asserted that the Combined Charging System will become the standard for all European vehicles by 2017. However, other auto companies, notably Nissan and Mitsubishi, have protested the standard, and Tesla Motors (a U.S. DRIVE partner) has not adopted it.

The technology uncertainty concerns the rate at which the following might occur: (1) the Combined Charging System or some other widely accepted charging standard will be adopted, (2) a new generation of plug-in vehicles able to accept fast charging will appear in the marketplace, and (3) electric utility companies can upgrade transformers, substations, and distribution networks to accommodate the increased power demand.

At the same time, uncertainty exists over the pace of adoption of smart-grid technologies. On the utility side of the meter, smart-grid systems could prove more resilient to unanticipated changes in power demand brought about by fast charging. And on the customer side of the meter, smart micro-grids could manage the recharging of a plug-in vehicle in any prearranged manner. However, the rate of adoption of these technologies cannot be assured to match the rate of adoption of the vehicles.

Policy Uncertainty

The economic incentives for owners to charge their vehicles during times of low grid impact and for electric utility companies or unregulated entities to invest in charging infrastructure fall largely to the utility rate-making authorities in each state. This poses a challenge to achieving the uniformity of national (indeed, international) infrastructure required to support electric vehicle deployment. Here, DOE can exercise its national leadership capabilities to encourage a stable and productive policy environment. This, in turn, would likely reduce the other uncertainties in customer behavior, technology adoption, and infrastructure investment.

A DOE strategy that would exercise leadership from the national perspective will be essential for the prompt and efficient deployment of an electric charging infrastructure. The kind of leadership needed cannot be left to the grid interaction technical team alone. Effective leadership can help clarify the policy environment and lead to more uniform state policies for the build-out of charging infrastructure. Reducing policy uncertainty could, in turn, lower the anxiety felt by prospective plug-in vehicle owners about charging their vehicles in a cost-effective, timely, and environmentally friendly way.



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