EVs Powered by the Sun
A panel and a Tesla. Photo courtesy Zan Dubin Scott.
For electric vehicle (EV) advocates, there is nothing more appealing than opportunities to charge EVs on completely emissions-free solar power. There are challenges associated with wide-spread adoption of solar-powered EVs, but exciting solutions and innovations are beginning to emerge –- for both individuals and institutions. Recently, I had the chance to talk with Christof Demont-Heinrich, the creator and editor of SolarChargedDriving.com. He said that before the Chevy Volt and Nissan Leaf came on the market last December, it was estimated that about 50 percent of EV drivers also had solar panels on their roofs, and that at least 1,000 people are currently charging their EVs with solar.
Demont-Heinrich said that about 1.5-3 kilowatts of solar power are needed to charge an EV. Additionally, one would need about 5-7 kilowatts for the electricity needs of the house, with a total of 7-10 kilowatts for home + EV. If someone already has five kilowatts of solar power generation on his or her roof and wants to add more to accommodate the EV charging, Demont-Heinrich said that the ease or difficulty of that project would depend on whether one had installed a solar inverter that can handle another "string" of solar panels. He said that micro inverter systems may be one type of system well-equipped for this type of upgrade.
Most people, even those with solar panels on their roofs, draw from the electricity grid, and that grid is not always reliant on one's solar panels –- particularly at night or on cloudy days. And night-time is when most EV advocates want to encourage people to charge their EVs –- when there is less strain on the grid and when there are greater opportunities to rely on wind power. This is no reason to give up on the idea of solar-powered driving, said Demont-Heinrich. He argues that with solar panels, you're doing a significant amount of EV charging off the sun, and you're cleaning up the grid overall when your excess solar power feeds back into the grid.
Meanwhile, off-grid solar EV charging options are beginning to emerge. At the Wheeler Army Airfield in Honolulu, Hawaii, the US Army recently installed the Smart-Charging Micro Grid system, a photovoltaic upgraded carport that provides 25 kilowatts of solar power and 200 kilowatt-hours of battery storage. It will power four plug-in electric vehicles. The buildings are independent of the commercial power grid and are part of a pilot program that will help the army reduce the amount of fuel it transports over supply lines throughout the world.
The Brooklyn Bridge Park recently announced that the renewable energy company Beautiful Earth Group was installing New York City's first solar-powered EV charging station. The station will be able to charge five electric park service vehicles and a full-size electric car. It is estimated that the station will save more than $200,000 in gasoline and tens of thousands of dollars in electricity over the 25-year lifetime of the project. An estimated 530 tons of CO2 would have been emitted during this period if traditional service vehicles had been used.
In a blog article last November, Sierra Club's Brian Foley interviewed Envision Solar's President and COO Desmond Wheatley about the company's partnership with General Motors to build solar trees that will charge Chevy Volts at GM's headquarters and dealerships. More recently, Ford Motor Company launched a solar energy system to help generate electricity at its Wayne, Michigan assembly plant. Through 10 EV charging stations, the renewable energy from the system will be used to help power and test the new plug-in electric version of the Ford Focus, the C-MAX Energi plug-in hybrid, and electric switcher trucks that transport vehicle parts at the manufacturing site. Additionally, Ford will test how electric vehicle batteries can be reused as stationary power storage devices after their life in the vehicles has been exhausted. When the plant is inactive, the collected solar energy will be stored and can be used to help power the plant when there is insufficient sunlight.
-- Gina Coplon-Newfield, Sierra Club Senior Campaign Representative for Electric Vehicles