Monday, April 23, 2007

Building-integrated photovoltaic solar power


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"Utility rates are only heading one way -- up," says Brad Dougherty, a mechanical engineer working with BIPV solar cells at the National Institute of Standards and Technology.

Solar power systems cost about 90 percent less than they did in the 1970s, and prices have been dropping about 5 to 7 percent each year, according to the Solar Energy Industry Association. Solar power is a hedge against rising energy prices.


Story by Denise Trowbridge
April 16, 2007
BizRate.com

If you want free electricity from the sun but don't want rows of pool-table-sized solar panels destroying the lines of your roof, there's now an easier, more attractive solar option.

Building-integrated photovoltaic solar power, or BIPV, has taken the ugly and awkward out of residential solar power systems.

Simply put, BIPV is the mixing of solar power cells into materials you'd normally see on a building, such as roof shingles or the UV coating on a window or skylight.

It's most popular application is the solar shingle, where solar cells are glued or mounted to the surface of a common roofing material, such as slate, cement or asphalt. The shingles are then installed just like a traditional roof. The solar panels are no longer on the roof, they are the roof.

The technology has been around for about five years, but it's become more popular recently, thanks to declining prices, federal tax credits and state incentives for homeowners installing alternative energy systems.

Homeowners qualify for a tax credit of 30 percent of the cost of a solar power system, up to $2,000. The credit, which reduces the tax owed dollar-for-dollar, was set to expire in 2007 but has been extended through 2008. Most states offer additional incentives, including grants, low-interest loans and state tax deductions.

When combined, incentives can lower the upfront costs of installing a solar power system by 60 to 70 percent, says Noah Kaye, director of public affairs with the Solar Energy Industries Association.

The typical American household uses about 10,656 kilowatt-hours of electricity each year, or about 888 kwh per month, which means a 6 kw solar power system would be needed to cover all of that home's electricity needs.

A one-kilowatt BIPV solar roof system costs about $14,000 before incentives, says Art Rivera, marketing representative for Sunslates, a solar roof tile manufacturer in Sacramento, Calif. At that cost, the typical American family would have to spend $84,000 to generate all the electricity it uses.

That price tag is out of reach for many Americans, which is why most homeowners opt for a partial solar electricity system. Most install 2 to 3 kw systems, Rivera says, which can reduce electricity bills by 25 percent or more. Homeowners on a budget also have the option to increase the capacity of their system over time, as they can afford it. Most solar electricity systems are modular, so more solar panels or shingles can be added to the current system after it's installed.

Each 1 kw shingle system requires about 100 square feet of roof space and produces between 1,600 and 2,000 kilowatt-hours of electricity each year, depending on where you live. If electricity costs 10 cents per kilowatt-hour, each 1 kw of solar power would reduce your electricity bill by $160 to $225 each year for the life of the system. Solar shingles typically last 20 to 25 years, and are designed to withstand hail and tropical-storm force winds.

Lower utility bills for the future are a big part of the appeal.

"Utility rates are only heading one way -- up," says Brad Dougherty, a mechanical engineer working with BIPV solar cells at the National Institute of Standards and Technology.

Solar power is a hedge against rising energy prices.

"It's like buying a car that has 25 years of gas in the tank," Kaye says. "The fuel is free, so the upfront cost is the only cost."

Add in the environmental benefits, which include reduction of greenhouse gases linked to global warming, and it's a win for consumers.

It doesn't hurt that solar power systems can also boost the resale value of real estate.

"Homes with solar (power) sell for more," says Brad Collins, executive director of the American Solar Energy Society. "The resale value solar adds to a house is often more than the cost of the system."

That's music to homeowners' ears in a rocky housing market. It's also become a selling point for homebuilders.

Developments where BIPV solar roofs are standard issue are popping up all over California. About 30 neighborhoods there are using SunTiles, a BIPV roofing material, on all or most of the new homes built in those developments, including a 650-plot Lennar Homes project in Roseville, Calif., that claims to be the world's largest all solar-powered community.

But solar power isn't just for the Sunbelt. It can make just as much sense in Boston as in Albuquerque, N.M. "Photovoltaics produce 25 percent more power in Albuquerque, N.M., but Boston's electricity rates are much higher, so the savings are about the same," Kaye says.

Figuring out if it makes sense for your home can be complicated. The time it takes to recoup your investment in solar power varies by region, but some basic rules apply everywhere.

For instance, solar power does best on a south-facing roof. Electricity production falls about 15 percent if the roof is facing east or west. And the more you pay for electricity, the less time it will take to recoup your investment. There are online calculators to help you crunch the numbers for your neighborhood.

It may seem like common sense, but working solar into your home-improvement schedule can save money, too. If you need a new roof anyway, or if you're building an addition onto your home, installing BIPV instead of traditional roofing can be a good option, Dougherty says. The price tag is comparable.

"But if your existing roof is in good shape, it doesn't make sense to replace it," he says. If your roof has a few more years of life left, traditional rack-mounted solar panels might be a better choice.

Net-metering standards also come into play. Most solar roofs are net metered, meaning they are tied to the traditional electricity grid. Net metering allows homeowners to buy traditional electricity from the power company when their solar system isn't producing enough. When it's generating more than the homeowners need, they sell electricity back to the power company. Not all states allow net metering.

Installation costs vary as well, due to local labor costs. BIPV isn't quite a do-it-yourself project yet, but installation is simple. The pieces can be installed by just about any qualified roofer, and are then tied into the utility grid by an electrician.

If you're on the fence about solar power, it could pay to wait a year or two. In the near future, solar options might make more economic sense to more people. Solar power systems cost about 90 percent less than they did in the 1970s, and prices have been dropping about 5 to 7 percent each year, according to the Solar Energy Industry Association.



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