It doesn't look like the leaves changing colors and piling up on the lawn, but a nature-inspired "artificial leaf" technology has taken a notable step toward the goal of producing storable and clean energy to power everything from factories to tablet computers.

The leaf is a silicon solar cell coated with catalytic materials on its side that, when placed in a container of water and exposed to sunlight, splits the H2O into bubbles of oxygen and hydrogen. The hydrogen can be stored and used as an energy source, for example to power a fuel cell.

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"The device both captures the solar energy and stores it in the chemical bonds of the hydrogen and oxygen that are produced from the water," Steven Reece, a research scientist with Sun Catalytix and lead author of a paper describing the breakthrough, told me Friday.

 

You can check out the device in action the video below.

The artificial leaf is made entirely with earth-abundant, inexpensive materials — mostly silicon, cobalt, and nickel — and it works in ordinary water. Other attempts have required more expensive catalysts such as platinum and/or extremely caustic water, noted Reece.

"What was really novel about our work is that we were able to integrate our earth-abundant catalysts with this commercial triple junction solar photovoltaic technology that would then operate under benign conditions without wires and a reasonable efficiency," he said

The breakthrough was led by Daniel Nocera at the Massachusetts Institute of Technology and was reported Thursday in the journal Science. Reece worked in Nocera's lab before moving to Sun Catalytix, which was started by Nocera to commercialize his solar energy inventions.

This new paper is the latest step in a process that has generated buzz over the years.

In 2008, the team reported on the cobalt part of the equation, which releases oxygen from water. They've now coated the other side of the silicon sheet with the nickel-molybdenum-zinc alloy, which releases hydrogen from water molecules.

"You just drop it in a glass of water, and it starts splitting it," Nocera said in a statement. 

He added that the device is not ready for commercial production as the systems to collect, store, and use the gases remain to be developed. "It's a step," he said. "It's heading in the right direction."

The collection and storage of the sun's energy as hydrogen fuel is a key step in overcoming one of the limitations of solar power — it generates energy when the sun is shining, but it needs to be stored somewhere to be useful at night and in cloudy weather. 

Batteries are one place to store the energy, but battery technology, while improving, is limited. Storing solar energy as hydrogen fuel could be an answer.

"Nobody disputes the beauty of the chemistry," reads a Nature News article about the technology. "But whether the system is actually useful will come down to how expensive the hydrogen is to make, and how efficiently the system can use the available energy from sunlight."

More on energy technology:

• Up a tree no more, a 'real' artificial leaf debuts
• Fuel cell breakthroughs reported
• Scientists develop self-healing solar cells
• Green energy ideas so crazy they just might work

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John Roach is a contributing writer for msnbc.com.

 

 

You might not think of electric cars as long-haul vehicles, but months of real-world driving reveal that they can be long-distance marathoners — under the right conditions. Chevrolet, for example, is reporting that the average Volt driver is going 1,000 miles between gasoline fill-ups. And for the most part, Nissan Leaf owners are perfectly happy to do without the gas tank altogether.

It's been six months since we first took to the highways for our first "Electric Road Trip," which is enough time for electric-car automakers to work out the bugs in the system. Nissan came across a software glitch that could keep the battery-powered Leaf from starting, but the main issue has been availability. Only 5,300 Leafs have been sold worldwide, including about 500 in the United States. But Nissan says it will be accelerating production and taking reservations again as of May 1.

Meanwhile, Chevrolet has sold about 1,500 Volts as of the end of March, and the company says sales will be going nationwide by the end of the year. The company has been keeping track of Volt driving patterns through its OnStar network, and the data suggest that Volt owners are getting savvier about maximizing battery use and minimizing use of the car's gasoline-powered "range extender." During March, the average mileage between fill-ups went from 800 to 1,000 miles, Chevrolet reported last week.

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Chevy pointed to two Volt owners in particular: Gary Davis of Greenville, S.C., said he went two months between gas purchases and figures his gasoline usage at 547 miles per gallon. Steve Wojtanek of Boca Raton, Fla., said that 2,225 of the 3,417 miles he recorded were driven on battery power, which works out to 122 mpg.

Those figures don't take the electricity expense into account. The Environmental Protection Agency's rating suggests that the Volt gets the equivalent of 93 mpg on electricity alone, 37 mpg when the gasoline engine is running, and 60 mpg for combined battery-gasoline power. The Leaf gets a combined EPA rating of 99 miles per gallon equivalent.

Your mileage may vary
When it comes to electric cars, that age-old saying — "Your mileage may vary" — never rang truer.

"It's almost a game to see what you can do to get the best mileage out of it," Wojtanek said of his Volt.

Wojtanek told me he's changed his driving style to boost the Volt's efficiency. Quick starts or stops are kept to a minimum. It also helps that most of his trips are short jaunts around Boca Raton, which provides plenty of opportunities for charging up between drives. Pretty much the only time the gas engine turns on is when the 55-year-old commercial actor (and retired airline pilot) takes a trip to Fort Lauderdale or Miami. The round trip to Miami is 98 miles, and generally the gas kicks in after about 40 miles of all-electric driving. "Forty-three miles is about the best I get on the battery," he said.

Wojtanek, who counts a Rolls-Royce and even a replica Batmobile among his past purchases, said the Volt ranks high on his list. "This is the first Chevy since I had a Corvette back in 1991. ... For my driving, this is the best," he said.

He acknowledged that if you consider economics alone, it'll take a long time to make up the difference between a standard gasoline-powered car and the Volt, which retails for more than $40,000 before tax breaks. "The question is, how long does it take to recoup the cost?" he observed. "Every time gas prices go up, the time to recoup gets shorter."

Getting smart about batteries
The Nissan Leaf is cheaper ($33,000 before tax breaks), and the fact that it doesn't use a single drop of gasoline is especially appealing for electric-car purists. But gasoline-free operation also means that the Leaf has a more limited range, and some have complained that the car can quickly run out of juice and leave a driver stranded.

"Some knowledge about lithium-ion batteries helps," Patrick Van Der Hyde, a Seattle-area Leaf owner, told me today.

When the Leaf's battery gets near the end, it can deplete quickly, depending on the driving conditions. "All sorts of things affect range, just like all sorts of things affect gas mileage," said Van Der Hyde, who works for an electric-grid management company. "We average about 10 trips a day in the car, and most of those drives are five miles or less."

Van Der Hyde said he can expect to get 70 miles of "straight-out freeway driving" from a full charge, or closer to 100 miles if the car is in Eco-mode and he sticks to roads where he can travel 40 to 50 mph.

In the five months since I put the Leaf through its paces, dozens of electric-vehicle charging stations have been added to the Department of Energy's list for the Seattle area, but Van Der Hyde said the Leaf will really come into its own when fast-charging DC electric stations are installed throughout the region. That will enable the car's owners to get a full charge in a half-hour, as opposed to about seven hours for a 220-volt home charging station or 16 hours for your standard 110-volt outlet. (Right now, the Department of Energy says the closest DC fast-charger is in Portland, Ore., which is more than 170 miles from Seattle.)

'Primary car' ... except for road trips
Van Der Hyde said his family uses the Leaf as the "primary car in the way we think about it," and keeps a Honda Odyssey around for road trips.

That's the same strategy followed by Jon Hoekstra, senior scientist with The Nature Conservancy, who was the Seattle area's first Leaf owner. He uses the Leaf for commuting, for the occasional trip to the airport (which has plug-in parking stalls meant for electric vehicles) and even quick jaunts out of town.

"It does everything we need our car to do with the exception of road trips — and that's OK, because we didn't expect that," Hoekstra told me today.

Hoekstra and his wife bought the Leaf back in December to reduce their carbon footprint, and their fuel bill as well. "It really doesn't take much juice," he said. "I think I figured it's 3 cents a mile."

As much as possible, he tries to treat the Leaf like a regular car. "I deliberately have tried not to be a 'hypermiler,'" he said. In the first four months of driving, there's been only one time when the family felt the fear of running out of power. Hoekstra said that happened because the car wasn't fully charged up before the trip, and because nasty weather reduced driving efficiency — all contributing to a perfect storm for range anxiety.

Fortunately, the Leaf made it back home before the electricity ran out. "Other than that one occasion, it's been great," Hoekstra siad.

Do you have electric-vehicle experiences to share? Are you on a waiting list, or are you waiting for other EVs such as the Ford Focus Electric or the plug-in Prius to make their appearance? Feel free to weigh in with your comments below.

More about electric vehicles:

• Nissan Leaf and Chevy Volt get top safety ratings
• Chevy Volt offers a taste of electric car's future
• Video: Get set for 'Revenge of the Electric Car'
• Toyota eyes magnesium batteries for EVs
• 10 electric cars you can buy in 2011

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