April 4, 2008

Peel-and-stick solar panels help power Phoenix Convention Centre

Phoenix

The simple idea that gave us stickers and budget floor tiles will help power the Phoenix Convention Centre.

Early this month, crews will install peel-and-stick solar panels on roughly a third of the West Building’s two-acre roof, according to a story in the Arizona Republic.

The panels will help supply power to the building, which was completed in 2006. How much of a dent that will put in its power consumption is unknown, but the amount is probably a small fraction of what the building will use, city officials say.

The important thing, says councilman Greg Stanton, is that the panels are a groundbreaking effort for Phoenix.

The US$850,000 project will be the biggest solar-panel installation on a downtown Phoenix building, and it’s the first time this type of solar-energy technology has been used by Phoenix, officials say.

Down the road, the technology could be used to provide a cheaper, easier, more attractive way to provide solar power to some existing buildings. Although other area cities have used the peel-and-stick solar panels, the convention-centre project is among the largest to date, officials say.

Using sun power will cut the center’s carbon-dioxide pollution by 95 metric tons each year, according to the city.

“Phoenix and other governmental entities should show leadership on this issue,” said Stanton, who oversees a city subcommittee on sustainability.

In general, conventional electricity usually costs about 8 to 10 cents per kilowatt-hour, and electricity generated by solar power costs about 20 to 30 cents per kilowatt-hour, said Arizona State University solar-power expert Govindasamy “Mani” Tamizh-Mani.

When crews roll out 732 solar panels on the roof, it should provide 150,000 kilowatt-hours of electricity annually, said Mark Holohan, president of Code Electric, the company doing the installation.

“High-rises are tough solar applications because there are lots of things that want to be on a small rooftop, like helipads, radio antennas and air-conditioning systems,” Holohan said.

Also, raised panels on high-rises could be blown off by wind. On smaller downtown buildings, shadows could make them less effective. But the thin, peel-and-stick panels are easier to use on the convention centre. They lie flat, and strong glue bonds them to the roof.

The solar-panel sheets are coated on one side with an ultrathin layer of amorphous silicon. The light-collecting layer is 1 per cent of the thickness of a human hair.

In the Phoenix area, the most common solar panels are made of silicon wafers covered in glass.

They are much heavier. Few projects use peel-and-stick panels, though they are less expensive and many feel they are better looking, said Tamizh-Mani, who is the director of Arizona State University’s Photovoltaic Testing Laboratory.

At the moment, from the market point of view, more than 90 per cent is the wafer technology, and probably this represents less than 5 per cent of the market,” he said.

Traditional silicon wafers are about 100 times thicker and soak up rays much more efficiently than thin sheets, he said.

So if a customer is looking to get the most power out of a small area, wafers often win out, Tamizh-Mani said.

Now firms are exploring ways to make the thin solar panels more efficient, he said.

Thin solar panels are appealing to city leaders because it would be easier to add them to existing buildings, Stanton said.

Similar panels have been installed on government buildings from Mesa to Glendale but on a smaller scale than the convention center.

Luke Air Force Base, however, has a larger system.

After the panels are installed, city officials will carefully note how much electricity they actually produce, said Larry Kraft, a capital-improvement manager for the convention center.

“It’s like when you buy a car,” he said. “You have to drive it to see what the actual miles per gallon are.”

DCN News Services

Print | Email | Comment