Transportation Researchers Present Findings and Recommendations on Electric Vehicles and the Grid to California Policymakers

Sac Briefing - Tim, Gil, and Austin Speaking to Group

Kicking off a series of Capitol briefings on transportation issues, last week, researchers from the Institute of Transportation Studies at UC Davis and at UC Berkeley (ITS-Davis & ITS-Berkeley) met with members of the legislative staff, transit agencies, non-governmental organizations, regulatory agencies, and the public. The briefing, organized by the California Senate Office of Research and UC Institute of Transportation Studies, was held to inform policy makers on current progress and potential future policies that can help California simultaneously achieve its goals for electric vehicle (EV) adoption and sustainable energy.

Gil Tal, Director of the Plug-In Hybrid and Electric Vehicle Research Center at ITS-Davis reviewed the current EV market and vehicle charging behavior. Tim Lipman, Co-Director of the Transportation Sustainability Research Center at ITS-Berkeley, proposed how EV-charging could be managed so that it uses more renewable energy. He also suggested tools to help utility customers charge EVs but avoid brief, sharp increases in their electricity use that lead to expensive “demand charges.” Austin Brown, Executive Director of the Policy Institute for Energy, Environment and the Economy at UC Davis, moderated the discussion and highlighted policy implications.

The presenters fielded a number of questions from the attendees, addressing issues such as whether it would be possible to manage charging times for large fleets, like electric buses, in addition to private single-vehicle owners; and whether remote control of vehicle settings or controlling the charger would be the better way to manage when a plugged-in EV is charged.

Following the briefing, Randy Chinn, Chief Consultant for the Senate Transportation Committee reflected: “These briefings are very useful, and this is a good time of year for them. It gives us in the Legislature time to digest the information before we are swamped in the next few months with legislative analysis and hearings.”

Key Take-Away Messages

  • 5 million EVs(the 2030 goal for California) will need 1-1.5 million “while-at-work” chargers and some DC fast chargers
  • Free charging is good for selling EVs but is not sustainable over the long-term and will lead to congestion at chargers.
  • Almost all (92-95%) of charging occurs at the origin or destination of a trip and not in between; so, we do not need many fast chargers to function like mid-trip gas stations.
  • Most EV charging occurs at home from 6 pm–midnight, which places the greatest demand on non-renewable sources of energy, while renewable sources (like solar) that are abundant during the day can sometimes go to waste.
  • We can change where and when people charge with pricing and charger availability, especially free vs. paid. (Smaller differences in the charge per kW-hour does not usually affect charging behavior.)
  • The widespread development and use of vehicle-to-grid interaction—where car charging patterns can be shifted both at a given location and between locations—can greatly increase the use of renewable energy.
  • Tesla still dominates the new EV market. (In 2019, 51% of new EVs sold in California were Teslas.)

Policy Implications and Recommendations:

  • Change our thinking and terminology on chargers from “home vs. work-place chargers” to “while-at-home vs. while-at-work.” This will foster policy thinking and infrastructure planning that will achieve greater socioeconomic equity, cleaner energy use, and reduced vehicle miles traveled. For example, using the terms “while-at-work” rather than “work-place” chargers opens our thinking, planning, and subsidizing to include chargers at commuter rail stops, public parking lots, and locations other than employers’ property. A while-at-home charger expands the discussion to encompass chargers available to multi-unit residences, not simply single-family residences.
  • Make while-at-work charging easier and less expensive for more people–i.e., facilitate a shift away from free work-place charging used on a first-come-first-served basis by very few EV owners with select employers.
  • Change timing mechanisms so that vehicle owners specify when they need the charge to be completed by (departure time) rather than when to start the charging.
  • Encourage EV owners to plug-in frequently and allow experts at car manufacturers or utility groups to control the time of charging through remote vehicle controllers or charger controllers. A pilot project showed that these methods can make the entire system more efficient and reduce the loss of renewable energy.

Three more briefings on other transportation topics are scheduled for March 6, 11, and 20. For more information, please visit:

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