Fill 'er Up with Sunshine: Green Cities Spark Demand for Solar EV Chargers

It's known as the Windy City, but its vehicle fleet could someday be powered by the sun.

Chicago unveiled its first solar electric-vehicle charging station this month as part of a campaign to bolster the city's green cred in its bid to host the 2016 Olympics. The 2.4-kilowatt battery system is small, but it demonstrates how city vehicles might someday be powered by a completely carbon-free fuel source: the sun.

The station is among only a handful of solar-powered vehicle chargers in the United States, and perhaps the first in the Midwest. They're few in numbers in part because electric vehicles are still few in number. Solar-powered charging stations are also more expensive than stations that draw electricity from the grid.

But the solar-powered chargers make a powerful symbolic statement: These vehicles run on clean energy, not fossil fuels.

That's why progressive cities across the country are investing in the infrastructure today, so mayors and city councils can claim bragging rights to being the greenest in the nation.

"Right now, it's all policy driven," said Richard Lowenthal, CEO of Coulomb Technologies, which partnered with Carbon Day Automotive to build the Chicago facility.

"In the absences of many [plug-in] cars, there are progressive cities and businesses that are saying we want to make a statement about oil independence and clean air."

About half of Coulomb's sales are to cities that want to show they are welcoming to electric vehicles and green technology, Lowenthal said. The company is seeing sales typically in small quantities, but geographically spread. "Every city wants a few," he said. "We know when the [vehicles] come, these cities will be ready to expand."

President Obama has called for more than 1 million electric vehicles on the road by 2015. Automakers are expected to begin selling plug-in hybrids on a wider scale later this year, with all-electric vehicles hitting the market as soon as 2010. For every car shipped, Lowenthal believes there will be demand for at least two charging stations.

Electric-vehicle owners will want to charge their cars wherever they park for long periods of time: at home, at work, at the mall or restaurants.

Odds are good that some of those stations will be powered by the sun.

"I can see the synergy between vehicle charging providing shade and generating electricity with solar becoming more prominent in the future," said Tony Markel, a senior engineer at the U.S. Department of Energy's National Renewable Energy Laboratory who studies how electric vehicles interact with the electric grid.

Chicago's charging station is unusual – and limited – in that it is not tied to the electric grid. A set of solar panels during the daytime charges a battery, which is used to charge city fleet vehicles at night. The most common model feeds all of the solar-generated electricity onto the grid, using it as a sort of "virtual battery" when it's not in use.

Another option is to forgo putting solar panels on the charging station and instead offset the electricity use with a renewable energy source somewhere else on the grid.

There's growing demand, however, for stations that generate solar electricity on the spot, Lowenthal said. "We were a little skeptical," he said. "Economically, it's not the best idea, if you just go by dollars and cents ... but this is dollars and cents and policy that make these happen."

Installing solar panels on vehicle charging stations isn't purely cosmetic, argues Paul Scott, a co-founder of Plug-In America, a coalition that promotes electric and plug-in vehicles. Scott is also president of the Electric Vehicle Association of Southern California and a residential solar installer by trade.

If vehicles are being charged on a sunny afternoon, generating solar power on the spot can help lower the peak electricity demands on power plants.

"We have abundant sunlight. Even in cloudy areas, there's enough to power cars," Scott said.

Solar is a smart addition to charging stations where it's appropriate, Scott said. It wouldn't be wise to invest in solar panels for a station that's shaded between two tall buildings, but in areas with prime sunlight and good rebate programs, the added investment will often pay for itself.

Scott sees potential for entrepreneurial parking lot owners to cover their lots with solar canopies and sell the electricity to vehicle owners and electric utilities. "Whoever owns the parking lot will be making money two ways. It'll quickly pay for the solar system," Scott said. "It's going to be a few years yet, but it's going to happen very quickly."

Santa Monica has about half a dozen parking structures that are shaded by solar panels. The National Renewable Energy Laboratory has one, too.

Markel said the initial goal was to provide a shaded parking area. In the summer, parking in the shade can help greatly reduce energy use because the vehicle's air conditioner doesn't have to work as hard to cool the vehicle once it's running again.

"Why not make that canopy out of PV panels? You're kind of doing a dual purpose, shading the car, but also collecting energy from the sun," Markel said.

He also emphasizes that one of the best ways to reduce demand on power plants is to generate electricity where it will be used.

"If you co-locate your power and vehicle charging, you have the shortest path of delivery," Markel said.

Solar charging stations are likely to be one of several ways that people power their vehicles in the future, he said.

"We're seeing people becoming innovative about how to bring these pieces together, and we'll have many more examples of integrating technology with electric vehicles," Markel said. "This is just the beginning."

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