Zero-emission vehicle (ZEV) targets set criteria for the minimum number or percentage of ZEVs that must be sold in a given year. ZEV policies should include interim targets, with a steady increase leading to the desired final year value. Because ZEVs are still an emerging technology, ZEV policies are often coupled with rebates or other incentives to encourage consumers to invest in the often more expensive upfront ZEV costs, though many electric vehicles are cheaper off the lot than gas cars from day one. Additionally, support for vehicle charging infrastructure is in important supporting policy.
The effectiveness of ZEV policies in reducing GHG emissions depends heavily on the composition of the electricity grid. In areas where the electric grid is made up primarily of fossil fuel sources, increased vehicle electrification can actually increase GHG emissions relative to the status quo. However, vehicle electrification will be important for meeting long-term goals for emissions reductions.
For passenger heavy duty vehicles (HDVs), these policies can either require a minimum proportion of the fleet be electrified, or can require that cities invest in infrastructure to electrify the bus fleet. For example, trolleybuses, which are common in many cities, draw power from electric lines place over streets. Because individual heavy duty vehicles are harder to electrify given their power and weight requirements, it may be necessary to have this infrastructure in place prior to achieving high levels of vehicle electrification.
For a more detailed discussion, see the applicable chapter of Designing Climate Solutions, our book on smart energy and climate policy design.