Lapping the Field: A Model Approach to Managing EV Adoption in Connecticut


Sales growth of plug-in vehicles well outpaced the auto industry as a whole over the first half of 2021 — just another piece of evidence that utilities and regulators must move quickly and thoughtfully to meet the fast-increasing demand for electric-vehicle infrastructure.

Now the Connecticut Public Utilities Regulatory Authority (PURA) has pulled to the front of the field with a new order, released earlier this month, that establishes a statewide zero-emissions electric vehicle program to be implemented by Connecticut’s two investor-owned utilities, Eversource and United Illuminating. PURA’s order covers most of the bases for proactive management of EV infrastructure, providing a model that other states could follow.

PURA has adopted a “make-ready” model for EV infrastructure, in which the utility owns the distribution infrastructure up to and including the meter, but the installer pays for the EV charger and station itself. The incentives, costs and benefits to build out more charging infrastructure are shared among the utilities and charger installers. The make-ready approach is favored because the alternatives either a) have utilities pay for everything, risking a shift cost to ratepayers with no incentive to control cost, or b) have charger owners pay the entire utility connection and charger costs, which would make chargers expensive for installers and also treat them unlike other installations that use make-ready service connections.

The EV order falls under the umbrella of PURA’s Framework for an Equitable Modern Grid, and Connecticut regulators see adoption of zero-emission vehicles as a key part of decarbonizing the economy in a way that benefits everyone. With that goal in mind, the order provides incentives for locating residential and workplace chargers in underserved communities. PURA has included a clear definition of what an underserved community in Connecticut is that will guide utilities and charger installers. There is also a particular focus on multi-unit dwellings, which the order notes are home to 10% of Connecticut residents. For chargers used by multiple tenants or homeowners, PURA intends to work further with the utilities to design an EV-only tariff; options explored in the order include a subscription model or deployment of technology to bill drivers directly.

As for single-family residences, they are already host to an estimated 13,800 non-networked Level 2 chargers throughout the state. To collect charging data from those without requiring that a second meter be installed, the order mandates a rebate program for purchase of a device that connects directly to the EV’s onboard diagnostic system. And Connecticut takes data collection seriously with mandated evaluation, monitoring and verification.

We know that EVs are a potential challenge to the grid if charging is managed poorly, on the other hand, EVs can be a beneficial flexible resource if charging is managed well. The Connecticut order includes automatic enrollment of EV chargers in demand-response programs (users can opt out). Direct participation in load management by a utility or third-party aggregator is an alternative, where the utility or the aggregator can reduce charging during pre-determined times of the day.

A notable area not resolved is whether to deploy another important tool in managing charging: rate design, specifically time-of-use (TOU) rates that incentivize charging off-peak when electricity is cheapest and the grid under least stress. The order notes that “an EV-only TOU rate for residential customers can be an effective tool for shifting customer charging behavior in order to minimize the grid-level impacts of transportation electrification.” But PURA decided not to mandate a TOU rate until after it has made a decision in a separate docket considering issues relating to advanced metering infrastructure. This is an area important to send customers the right price signals; otherwise, they will plug in when the grid is already most challenged.

A related challenge is commercial demand charges, which are potentially costly for owners of public charging stations and therefore a big issue for utility commissions across the country. While not making a definitive decision yet, the PURA order advances some modifications (EV rate riders as an interim option for the utilities) to set light-duty charging interim rates that vary on-peak and off-peak and go down as the charger utilization (measure in load factor of the charger) goes up. That’s a smart interim step to provide pricing that encourages off-peak charging and high-charger utilization during off-peak hours.

From a skybox perspective, the EV order puts Connecticut in the pole position for smart, thoughtful integration of the growing electric transportation sector with the electric utility sector. This is a PUC docket hopefully coming soon to a commission near you.