A Dynamic Look at EV managed charging and grid resource potential

Opinion Dynamics conducted a technology field test with two vendors that control chargers directly (ChargePoint® and Enel X®) and one vendor that leverages vehicle telematics to control EV charging (Geotab Energy®). The vendors responded to events called during the California peak period of 4:00-9:00 p.m. and the overnight period from 12:00 a.m. to 5:00 a.m., when most EV drivers charge their vehicles.

The field test revealed vehicle telematics and EV charger controls are both effective strategies for curtailing EV charging during DR events with minimal impact on participants. All vendors were able to successfully curtail most of the EVs under their control for each event.

We leveraged the EV charging load shapes from 71,000 EV owners in PG&E service territory to identify clusters of similar customer charging behaviors and common charging trends to further understand load management resource potential associated with scaling EV DR technologies to all EV owners in PG&E service territory.

The peak demand associated with EV charging PG&E service territory is greatest overnight (140 MW). As EV penetration increases, there is a growing risk that utility distribution systems may not be able to handle the increased capacity requirements for communities with exceptionally large clusters of EV owners that begin to charge at the same time.

EV ADR charging controls technology holds promise for mitigating these overnight peaks. Our analysis revealed the greatest EV DR load resource potential is between 12:00 a.m. and 4:00 a.m. (with a maximum resource potential of between 31 MW and 40 MW when extrapolated to the current population of 366,000 PG&E EV owners).

The study also examined EV charging during California’s system peak period of 4:00 p.m.–9:00 p.m. while the peak period resource potential is considerably lower than the overnight potential, 9–13 MW of EV load management resource potential is available during this period.

Our clustering analysis further revealed that 28% of EV owners are “overnight chargers,” who could be targeted to mitigate distribution system impacts in areas with high EV adoption (clusters 1, 2, 4 and 5). An additional 20% of EV owners are “peak period chargers” and would be good targets for DR efforts designed to curtail consumption during the peak period 4:00 p.m. to 9:00 p.m. window (clusters 3 and 6). Furthermore, 52% of EV owners are “variable and low-level chargers” and would be poor targets for EV DR programs (cluster 0).

Given these results, partnering with EV ADR charging controls vendors to stagger overnight charging could provide a low-cost alternative to investing in distribution system upgrades to mitigate the effects of increased penetration of overnight EV charging in coming years.

Load patterns also reveal there are opportunities to encourage EV owners to charge in the middle of the day when solar energy is readily available in California. Furthermore, our study results suggest that EV owners may be more amenable to charging during the middle of the day as they are more likely to be working from home in comparison to before the pandemic.

EV sales soared in 2021, nearly doubling 2020 sales numbers. With over 20 new EV models expected to hit showroom floors in 2022, analysts predict another surge in EV sales this year which makes understanding the impacts of the EV boom imperative to improve resilience and address emerging grid needs.

The projected exponential growth for EV adoption creates immense load management challenges and opportunities for utilities and grid planners.

Results from this study, which reveal the charging patterns of EV owners in the PG&E service territory – which comprise 20% of the EV owners in the US- can help utilities and resource planners across the US better understand and prepare for future EV grid impacts and the associated opportunities to manage these impacts.

Dive Deeper into the data
and findings

Our clients face unique challenges, and our staff at Opinion Dynamics are always looking for unique ways to tackle these challenges and be at the forefront of problem-solving solutions. Our resident experts, Hilary Polis and Jordan Folks offer deeper insight with their companion pieces spotlighted below. The full report is also available via PDF download.


You already have my thermostat, now you want my car too? By Hilary Polis


Designing EV DR Incentives. Presentation by Jordan Folks

Companion Post

Insights Highlighted: A dynamic look at customers’ perceptions of EV managed charging