Best of Both Worlds: Home Solar Giving Electric Vehicle Owners Cleaner Charging

Battery electric vehicles produce zero tailpipe emissions. But a previous Design News article asked some questions about the “greenness” of plug-in electric vehicles and BEVs, noting that the big-picture lifecycle emissions ultimately depend on the fuel used to generate the electricity they use. From that lifecycle point of view, an electric car propelled by coal-generated electricity can be considered less clean than one powered by electricity produced by renewable energy.

Some Design News readers pointed out in the comments section of the article that it ignored a key scenario that supports the greenness of EVs: the increasing proliferation of home solar charging by EV owners. In fact, in an August survey of 10,000 EV owners by the Ford Motor Co., 83% of respondents said they either had or would like to have a solar system at home, suggesting a lifestyle correlation around low-carbon, low-emissions technologies.

(Source: ReVision Energy)

“People don't generally call specifically to say, 'I'm looking for a solar array for my car,'” said Phil Coupe, co-founder of Portland, Maine-based solar provider ReVision Energy, in an interview with Design News. “They're telling us, 'I'm looking for solar energy to power as much of my lifestyle as I can.' For more and more people, that lifestyle includes an electric car.”

The stars might be lining up for those with such a lifestyle. Costs are falling for the installation of rooftop photovoltaic (PV) solar power systems. “The drop in cost means solar is much more practical for a wider swath of the population,” Coupe told us.

[Learn more electronics trends and developments at Pacific Design & Manufacturing, Feb. 9-11, at the Anaheim Convention Center.]

The Union of Concerned Scientists estimates that, in the US, rooftop solar was powering 400,000 homes in 2013 and could reach anywhere from 900,000 to 3.8 million by 2020. The Solar Energy Industries Association (SEIA) calculates that the US market for residential PV solar systems grew 69% from 2014 to third-quarter 2015. PV system prices have declined by some 75% over the past decade. That decrease, together with government incentives, has provided impetus to the growth of PV systems. However, SEIA cautions that some of the recent surge in growth is due to incentives expected to expire in 2017.

Given the growth of both the BEV and home solar markets, and the lifestyle correlation indicated by the Ford survey, it's no surprise that the overlap among adopters of these technologies is growing as well.

Providers of residential solar systems have been responding by offering solar charging systems to EV owners. According to ReVisionEnergy, the two primary components needed are a solar electric system and a Level 2 EV charging station, i.e., a hardwired appliance that can deliver a 24 kWh charge in four to eight hours, which is faster than a 120V outlet charger.

READ MORE ELECTRIC VEHICLE ARTICLES ON DESIGN NEWS:

Skeptics might note that typical EV drivers are away from home during the day, meaning they won't be able to plug their cars into the charger when the sun is out. But Coupe points out that with a solar system tied into the public utility grid, a consumer will be able to generate power during the day and sell it into the grid, producing a credit that can be used to pay for a charge-up at night. “In essence, the grid becomes your storage battery,” he told us.

Besides the environmental benefits of driving a solar-charged EV, homeowners are attracted to the financial savings, said Coupe: “It costs about four cents a mile to drive an electric vehicle charged with solar, compared to about 15 cents per mile for a similar-sized gasoline-powered car.” The steadily falling prices of PV solar have made the upfront cost of a rooftop system more affordable (with the average installed cost now under $5 per watt in the US). Coupe said many homeowners now are saving on upfront costs by leasing both their solar systems and their EVs.

Al Bredenberg is a writer, analyst, consultant, and communicator. He writes about technology, design, innovation, management, and sustainable business, and specializes in investigating and explaining complex topics. He holds a master's degree in organization and management from Antioch University New England. He has served as an editor for print and online content and currently serves as senior analyst at the Institute for Innovation in Large Organizations.

Like reading Design News? Then have our content delivered to your inbox every day by registering with DesignNews.com and signing up for Design News Daily plus our other e-newsletters. Register here!