EV owners more likely to install rooftop solar

Owners of EVs are more likely to add solar panels to their homes, according to a new behavioral study analysis from the US Department of Energy’s NREL.

The study, funded by the Department of Energy’s Vehicle Technologies Office, was based on a survey of 869 households in the San Francisco Bay area, first in 2018 and then again in 2022. It found that around about one-quarter of EV owners also own PV systems, while only 8% of people who do not own EVs have adopted distributed solar.

EV owners might have a tendency to also install solar since solar panels could help offset the energy costs of charging their vehicles at home, said Shivam Sharda, a computational research scientist at NREL’s Center for Integrated Mobility Sciences, and lead author of the study.

“Both EVs and PVs have a complementary nature, which might play a pivotal role in energy systems resiliency, addressing concerns regarding grid stability and power management strategies,” added Sharda.

On the flip side, the researchers found that owning solar panels could also influence whether homeowners buy EVs, although that correlation is not as strong.

Two aspects that could encourage a consumer to adopt either solar or EVs, or both include being aware of the technologies, and being social enough to ask about them, the study determined. For instance, if someone has a friend or family member who owns a rooftop solar panel or EV, they become more educated about the technology and its pros and cons, thereby influencing their decisions, said Sharda.

From a policy perspective, while governments currently incentivize the adoption of both EVs and rooftop solar, the study recommended implementing strategies that could accelerate the deployment of the two technologies jointly.

“Because EV owners are inclined to use PV anyway, such incentives might provide a push for EV owners to adopt solar technology much earlier than what is currently observed,” NREL said. “How soon a household adopts cross-sectoral sustainable technologies will play an important role in achieving decarbonization goals.”

The study also highlighted the need for additional holistic surveys to better understand the nexus of transportation and residential energy use.

A 2021 consumer report from SolarReviews found that an EV would cost about  $1,058 per year when using a public charger, but that costs drop to as little as $415 annually with home solar – compared to the $1,260 a year it costs to fuel a traditional, gas-powered car. The report compared a gas-powered Hyundai Kona with an all-electric one, and found that during a 13,500-mile year, the former would cost $1,260 to fuel, while the latter, when charged at home, could cost around $662 per year in California and $450 annually in a state like Florida. In fact, over a 25-year period, charging an EV with home solar could save the owner some $16,250, the study concluded.