In late 2020, Roanoke Electric Cooperative, energy technology company Fermata Energy and a team of clean energy organizations, including Advanced Energy, launched a pilot project to explore the potential of electric vehicle (EV) “vehicle-to-X” (V2X) applications.
V2X is an example of EV vehicle-grid integration, which explores and deploys strategies that help EV charging benefit rather than strain the electric grid. V2X in particular refers to the ability to send energy stored in an EV’s battery back to the grid (V2G), to a building (V2B) or to a home (V2H) when the vehicle is parked and plugged in.
Roanoke Electric’s pilot evaluated the potential of V2B using a Nissan LEAF connected to a Fermata charger at Roanoke Electric’s headquarters in Aulander, North Carolina. Fermata’s V2X system is the first EV charging system equipment to meet the North American standard for two-way current as verified by UL.
The team studied three use cases. The first evaluated whether the technology could follow the load of Roanoke Electric’s headquarters and reduce its peak load in response to its highest measured monthly amount. Specifically, the V2X system would send energy in the LEAF’s battery back to the building as needed. Over a two-month period, Fermata reduced the headquarters’ peak billed demand by an average of 12.35 kilowatts (kW) and its demand charges by $234.65. Annual savings at this rate would be around $1,407.90. Importantly, Fermata noted that these outcomes were achieved in an application that had a lower-than-ideal peak load and relatively modest demand charges.
In the second use case, Roanoke Electric responded to a systemwide demand reduction call from the North Carolina Electric Membership Corporation (NCEMC) — Roanoke Electric’s generation and transmission cooperative. Used in this capacity, an EV can act like a smart thermostat or a grid-integrated water heater as a grid resource. However, in addition to reducing load like those technologies do (by limiting charging, similar to adjusting a thermostat’s setpoint temperature or delaying water heating, for example), V2X can also offset load by discharging energy from the vehicle’s battery at the appropriate time; it just needs to know how much load is available to offset and when to offset it.
Here’s how it worked in the pilot project: Usually a day in advance, NCEMC would deliver a signal to Roanoke Electric, who would inform Fermata. Fermata would then set up the V2X system to discharge at the anticipated peak period. Each scheduled request to reduce load lasted 2 to 3 hours, and Fermata’s charger could provide 15 kW of power both to and from the car. Critically, power was never sent back to the grid but rather just to the building, because the building’s baseload energy demand exceeded the charger’s 15-kW capacity and because Roanoke Electric chose settings for the charger that would have prevented it.
Early pilot results revealed that the V2X system reduced Roanoke Electric’s load by an average of 14.08 kW during the demand reduction calls. For Roanoke Electric’s actual billed system peak hour, the LEAF was discharging at almost 15.2 kW, which saved Roanoke Electric $238.79 in just one month. From this single activity, these findings suggest per-charger savings of approximately $2,653.97 per year.
In the third use case, which centered on grid resiliency, the V2X system followed and supported a diesel generator–based microgrid in an islanding event. In particular, Roanoke Electric’s headquarters isolated itself and ran primarily on the backup generator while the V2X system was able to transition into and out of the islanded state autonomously, providing supplemental power to the facility while separated.
The pilot project demonstrated V2X’s potential as a grid asset and its capacity to reduce and offset peak demand and save money. However, it also revealed challenges that will need to be overcome as the technology becomes more widespread. For example, two of the demonstrated use cases rely on predicting and communicating peak events ahead of time. If a peak period is predicted incorrectly or not communicated to the charger, the connected vehicle won’t properly respond. These issues are real-world obstacles revealed by this pilot, but greater experience in load-forecasting, combined with reliable communications protocols that work with V2X equipment, will resolve them and unlock significant demand reduction capabilities for utilities.
Overall, this collaborative effort has shown the potential value that V2X systems can have across cooperative service territories. Combining EVs and V2X could form a new demand response mechanism with tremendous benefits for electric cooperatives and their members.