April 15, 2010

The photovoltaic solar panels proposed for Ontario brownfield sites are typically mounted about three feet off the ground.

FOCUS | Demolition & environmental engineering

Solar panels a temporary solution for brownfield projects

IAN HARVEY

correspondent

The obstacles to remediating thousands of acres of brownfields and former landfill sites are really a massive opportunity to turn a cash drain into cash flow, says the Canadian Brownfields Association.

It is lobbying the Ontario Power Authority to support construction of large photovoltaic solar panel arrays on those sites to generate revenue while the owners work at remediating the ground.

While this is still considered a new use for brownfields and landfills in Canada, it has already been tried and tested in the United States and Europe.

CBA member and leading proponent of the concept ArcStar Energy Limited says the key to turning on the power is the level of Feed-In Tariff (FIT) the Ontario Power Authority sets for such ground-based solar panels. The company has been lobbying for a rate of about 44 cents a kilowatt hour. The FIT rates for small micro solar power panels is currently up to 80 cents per kWh.

“Current PV solar panels are about 17 per cent efficient (at turning available energy into electricity),” says Robert Willes, a partner in ArcStar.

“So, from about five acres, you can produce one megawatt of power.”

That’s enough, he says, to provide investors with a reasonable rate of return over 20 years and entice them to pay for installing the solar farms.

“The big thing is that the location has to be close enough to the grid to feed in and, of course, that we get a FIT contract for a defined period,” says Willes.

The photovoltaic solar panels are typically mounted about three feet off the ground and reach a height of about 10 feet, with a 30 degree incline facing south. They have black faces and follow the contour of the ground, appearing as low-profile back ribbons which may make them more acceptable to communities than larger, more visually intrusive wind turbines.

ArcStar’s role is to match investors with brownfield owners, to either buy the land out or partner with them in the venture.

Willes says one successful example of the concept is in Houston, Texas, where a 300-acre former landfill is part of an Environmental Protection Agency project that will become operational this year.

It is projected to generate 12.5 million kilowatt hours annually, about one percent of Houston’s demand and is designed to last 30 years.

Germany also has several brownfields generating sustainable energy.

ArcStar is exploring three potential sites in Ontario and 160 sites in the U.S., says Willes.

Part of the appeal of the design, says Willes, is that the panels are anchored not by concrete footings but through an engineered system that drills a “screw” device into the ground similar to guy-wires.

The “screw” is tailored to the type of soil, from soft ground to rock.

“The panels are mounted on a system from Germany which is like a tripod and can be adjusted even if the ground settles, which is common in landfills and brownfields,” he says.

As such, he says, there’s good scope for construction companies to bid on installation contracts when they go up for tender.

“There’s no specialized equipment and very little in the way of additional skills training needed,” he says. “Basically we put them in with a bobcat.”

Wiring is also required along with grid hook-up and construction of “huts” to house electrical equipment and power inverters.

Soil remediation or ground capping is expensive, observes Willes, adding that generating income over a period of years allows for bio-remediation of contaminated soil, an often slow process that can take up to a decade to complete.

If excavation or capping is required, the work can continue on those sections and the panels added later, with the panels taken down as needed and then reinstalled.

“They’re relatively easy to take up and put down,” says Willes.

“And so when the soil is cleaned up and the owner wants to construct a building, they can do that and simply move the panels and then when the structure is complete, put them on the roof and continue to earn revenue.”

ArcStar is also in talks with the Ontario Ministry of Transportation about placing panels on the slopped shoulders of highway cloverleafs and along the 400 series highways.

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