New program bundles solar panels, electric cars and hope for a greener grid


On Wednesday, three seemingly unassociated organizations announced a partnership they say will help consumers save money and cut back on carbon emissions, while also supporting an environmental advocacy group.

Under the “Drive Green for Life” program, shoppers who purchase or lease a Ford Motors electric vehicle will receive a $750 discount on the lease or purchase of a home solar electric system from SunPower Corp., with SunPower donating an additional $500 to the Sierra Club for each purchase. Experts say that linking electric vehicles and the solar panels that could potentially power them could help pave the way to truly low-emission motoring.

Jesse Simons, Sierra Club chief of staff. (Photo courtesy of Sierra Club)

Jesse Simons, Sierra Club chief of staff. (Photo courtesy of Sierra Club)

Electric vehicles are a small but growing segment of the automobile market. These “EVs” don’t emit exhaust, making them popular with drivers seeking to decrease their impact on air quality and the climate. But with two-thirds of electricity in the U.S. coming from carbon-emitting coal and natural gas power plants, critics say that EVs often just shift their pollution elsewhere.

To make electric vehicles cleaner, their owners need a clean electricity source as well. The new initiative seeks to close that gap by streamlining the co-leasing or co-purchasing of the EV and a clean power source. “It sounds like a great idea,” said San Francisco resident Spencer Fleischer, who already owns an EV and a home solar system. “I wish I had known before I spent the money.”

The new program follows a 2013 agreement that gives Honda owners a $400 rebate with the solar energy company SolarCity. But that deal isn’t tied to the purchase of an EV. “The [other] new twist this week is that a major environmental organization is getting engaged and encouraging their members to join the clean energy revolution,” said Sierra Club Chief of Staff Jesse Simons. Those members – there are about 150,000 in California alone – will be helping to support the environmental group in the process.

Homeowners who take advantage of the program will have two parts of a clean-driving system. But they’ll still be missing a crucial link. There is no direct connection from the solar panels to the electric vehicle battery. Due to the way that the energy grid is set up, the electricity production from solar panels re-enters the greater energy grid.

But that might not actually be such a bad thing, as appealing as a direct cable from panels to car might seem. First, solar panels aren’t much good at night, when cars are most typically parked at home. Second, charging EV batteries directly from solar panels essentially turns them into storage for solar power – and that could cut their useful life short.

“Batteries are the most expensive part of the electric vehicle,” said Jim Sweeney, director of Stanford’s Precourt Energy Efficiency Center. “They do not have a lot of charge cycle lives,” Sweeney said. “By using the battery of the car for energy storage, you are using up the most expensive part.” It’s a phenomenon familiar to anyone who has watched in frustration as a cell phone or laptop battery stops holding a charge after a few years of use and too many charges.

Still, even though the solar panels won’t directly charge the owner’s EV, the new program will still generate advantages. More clean electricity will be available to the power grid because of the solar panels, and owners will get discounted electricity bills as a result – program participants may see prices as low as $5 to “fill,” or fully charge, their car.

But scholars see potential for such programs to do more than transform the daily commute. They foresee a future “smart grid,” in which a modernized electrical grid uses digital information and communication technology to improve grid efficiency by getting more energy coming from homes into the grid, rather than going the other way.

This smarter grid would help reap the full benefits of both solar panels and electric vehicles. “Another important element is deciding when to charge the battery,” Sweeney said. The electricity that homeowners receive from the grid has different prices and emissions associated with it at any point in time. This is because not all power plants run all the time. There are base load power plants that are constantly producing power, and there are “peakers,” which are only turned on when demand is at its peak.

Currently, energy pricing is not always dynamic, meaning consumers pay a fixed hourly rate for their electricity, no matter how much or little it actually cost the electric utility to produce it. With more grid-to-vehicle communication, people could take advantage of real-time energy pricing reflecting the true price of energy – and save money and help keep the peakers turned off, by charging car batteries when the prices are lower.

That smart grid is still in the planning stages. But for now, the ability to co-lease a solar photovoltaic system and an electric car is a modest but real step in that direction. A small discount and the chance to support an environmental advocacy group at the same time will likely encourage more people to take that step now.