Spring 2014

Close to Home | Solar Power Makes Electric Cars Shine

Solar Power Makes Electric Cars Shine

With electricity and transportation being the two greatest contributors to global warming (generating 61 percent of total U.S. heat-trapping emissions in 2009), environmental impact has been a main driving force behind growing sales of solar photovoltaic (PV) panels and electric vehicles (EVs). But advances in design and manufacturing, along with smart policies, have also made these technologies attractive to consumers for budgetary reasons. For example, UCS members Jeff Pector and Shelley Coppock of Oakland, CA (below), view their 3.7 kilowatt solar array and two Nissan Leafs as “sound economic investments whose long-term financial benefits far outweigh the up-front costs.”

UCS research shows that, no matter where you live, EVs charged from the electricity grid produce lower global warming emissions than the average new gasoline-powered compact car with a fuel economy of 29 miles per gallon (mpg). Nearly half of Americans live in regions where EVs are cleaner than a gasoline vehicle rated at 50 mpg—topping even the most fuel-efficient hybrids. And as more renewable energy gets added to the grid, our electricity system becomes cleaner overall, reducing emissions from EVs even further.

While charging an EV does increase your electricity consumption, you will likely end up saving money overall. For example, if you drive 12,000 miles a year, charging a Nissan Leaf costs less than $500 per year on average, versus nearly $1,500 in fuel costs for a 29 mpg gasoline-powered car. EVs, which have fewer moving parts that wear out and fluids that need replacing, also have lower maintenance costs.

What about When It’s Dark?

As Jeff and Shelley have learned, it’s not necessarily better for the environment to charge their EVs only when their solar panels are generating electricity. During the summer, peak electricity demand (driven by air conditioning needs) largely coincides with peak solar panel output. Adding excess solar power to the grid from home owners like Jeff and Shelley reduces the need to turn on “peaking” power plants that are more expensive and often less efficient than plants that deliver steady (“baseload”) power. And because California, like most states, has a “net metering” program, Jeff and Shelley receive credit on their electricity bill for the excess power they generate.

Their utility, like many others, also has "time-of-use" pricing that varies based on demand. So by charging their EVs and using energy-intensive appliances like a dishwasher or clothes dryer during non-peak hours, they take advantage of lower prices; conversely, the utility offers a higher price for the power they generate during peak hours. Jeff and Shelley ultimately pay nothing for the electricity they use. “We may be hard-core environmentalists,” Jeff says, “but the cost savings are our biggest solar benefit each year.”

To help defray the up-front costs of solar panels and EVs, federal tax credits are available: up to $7,500 on EVs and 30 percent of the total purchase and installation costs for solar panels. Additional incentives such as rebates, property tax exemptions, and discounted electricity rates for dedicated EV chargers may be available from your state or utility; visit www.pluginamerica.org/incentives and www.dsireusa.org for a list of incentives in your state.

Even if you can’t install solar panels, you can still invest in clean electricity to help charge your EV by enrolling in a utility’s “green power” program or buying renewable energy credits. Visit www.green-e.org for a list of options in your state.

Also in this issue of Earthwise:

Ask the Scientist

Does eating fish caught off the U.S. West Coast pose a risk due to radioactivity from the Fukushima nuclear accident?