Electric Vehicle Charging Infrastructure Recommendations to Fairfax County

Plug-in vehicles feature prominently in the vision for a livable, sustainable Tysons Corner. They promise cleaner, quieter transportation that is less dependent on the political stability of other parts of the world, but they come at the price of being a fundamentally different way of powering the automobile fleet. Charging will largely be done over long periods of time at distributed locations, rather than at particular fueling stations. As Tysons Corner evolves from a suburban office park to an urban center, the evolution to an electric automotive fleet will affect urban layout, building design, and utility services.

Fairfax County is attempting to determine the effects of widespread plug-in vehicle adoption on infrastructure requirements and to determine design approaches that can be considered through the county's zoning process to encourage appropriate investment. MITRE, in support of the County's sustainability objectives, has considered the problem under Proffer #9, RZ 2008-PR- 011. This document is the result.

We present a background for plug-in vehicles, charging stations, and other estimates of plug-in vehicle market penetration. We emphasize the impossibility of a demonstrably accurate estimate of market penetration, the fact that vehicle charging will be done primarily at home, and that modifications to initial parking area construction can reduce the overall cost and risk of installing charging stations. Four primary recommendations result:

1. The County should strongly encourage developers to include the conduit infrastructure—space, conduit banks, conduit, and access points—for relatively easy and inexpensive installation of charging stations in the future. The County should encourage, but place less emphasis on, the full installation of electric vehicle supply equipment (EVSE)—the transformers, switches, wiring, and charging stations themselves—at the time of initial construction given the uncertainties surrounding electric charging station demand.
2. The fraction of parking slots for which the infrastructure should be included should represent a fully plug-in fleet for the groups of users that would use charging infrastructure at the facility. This means all parking spaces for a residential building (single- or multi-family). At commercial and retail facilities, this means the fraction of vehicles that arrive from locations geographically situated to require a charge before the return trip.
3. The County can most appropriately seed charging station supply by negotiating for the installation of full charging stations at the lowest expected adoption rate in the near future. Any supply seeding is best done at apartment buildings and should be limited to a maximum of 2% of all parking spaces.
4. The County should coordinate with its peer jurisdictions to encourage charging station manufacturers to form a standard defining the connection of the charging station to the facility in which it is installed. The standard should define both the electrical connection and physical mount with the purpose of making it possible to move charging stations to a new facility relatively easily and quickly.

The objective is to prepare Tysons Corner for widespread plug-in adoption, but to do so as inexpensively as possible so as to encourage the desired population and job growth that will sustain Tysons Corner as a livable urban center.