Part 4: EV Charging Solutions

Managed Charging 101

Managed charging is the key to maximizing benefits to the utility, the grid, and the environment. It provides tools for utilities to manage charging behavior and move loads from peak to off-peak times or times of excess renewable generation when wholesale power is inexpensive or renewables are curtailed.

Managing this new load is essential to avoid potential issues on the utility’s distribution system and costs associated with higher coincident peaks. It is also far easier to begin a customer’s (or a fleet’s) electric vehicle journey with managed charging rather than disrupting established behaviors down the road. The utility can once again act as a trusted source to help reduce costs for the general public and fleet customers by harnessing EVs as a grid asset rather than a potential liability if charging is unmanaged.

EV benefits climb dramatically when charging is managed. An E3 study in the Pacific Northwest from 2019 found that moving charging to light load hours can roughly double an EV’s net economic benefits for the ratepayer. Depending on the utility, their load profile, and demand charges from the G&T, there may be times where active managed charging might move charging to heavy load hours to reduce demand charges from the G&T. Regardless of when it is most advantageous for vehicles to charge, managed charging is the key enabling this flexible load.

Managed Charging Programs

Rate structures play an important role in designing any type of managed charging program. The differential between peak and off-peak times is the key to incentivizing passive or active managed charging programs. Advantageous off-peak rates can help speed EV adoption, especially for fleets, by lowering total cost of ownership (TCO) for vehicles and reducing payback times for potential cost differentials between ICE and electric vehicles.

It is important to provide an excellent customer experience by prioritizing customer driving needs where customers can select their desired state of charge by a given time of day (i.e., 80% SOC by 7am) or easily opt-out some days.

Passive Managed Charging programs rely upon shaping customer behavior to affect charging patterns (also called behavioral load control). Education campaigns, apps, or fleet telemetry tools may help utility customers voluntarily shift charging behavior. The peak/off-peak differential is key when developing managed charging programs to effectively move when charging occurs by passing on savings to customers (from residential to commercial).

Active Managed Charging is the most robust form of managed charging that gives the utility (or a third party) the ability to control either when a vehicle charges or how much power a vehicle draws from the grid. Utilities or aggregators use dispatch signals via communications sent to vehicles, EVSE or smart panels etc.

Unidirectional controlled charging (V1G) is currently the most common form of active managed charging. V1G technologies can help balance the grid and support large-scale EV charging needs by selecting optimal times for charging and adjusting power levels based on grid conditions. This load balancing helps to reduce peak loads. By shifting and flattening load peaks, a utility can reduce peak power costs and make greater use of its generation assets, especially renewables. V1G can also reduce stress on customer circuits, transformers, and distribution substations — which helps avoid the need for costly infrastructure upgrades by both customer and utility.

Load control is primarily managed through EVSE wireless connections or by automaker telematics via onboard API software. Some are exploring smart circuits or smart electrical panels. Recent advances may soon allow utilities to leverage advanced metering (AMI) with demand response protocols (DERMS). The use of open standards like the Open Charge Point Protocol (OCPP) will help future-proof active managed charging investments and prevent stranded assets.

Bidirectional vehicle-to-grid (V2G) is the next level of charge control, in which electric vehicles can send power back to the grid. EV batteries can act as portable power stations by dispatching power when needed during periods of constrained capacity and drawing power during periods of abundant energy supply and low wholesale prices. Some distribution utilities are negotiating for exposure to wholesale prices in order to maximize V2G benefits. This need for revised power contracts will grow as V2G scales.

Pilots are growing in scale to demonstrate the true power of this technology, including many pilot projects underway with electric school buses. They are an ideal use case with large batteries, long idle times to recharge overnight, and a tendency to be idle during evening and summer peak demands. Bidirectional vehicle-to-anything (V2X) technology is evolving rapidly. It is important to begin planning and deploying pilots in order to be prepared for this exciting opportunity as it goes mainstream. Open standards including ISO 15118 and OCPP are key to future-proofing.