Solar roof tiles and shingles, also known as Building Integrated Photovoltaic (BIPV) panels, could become the standard for solar roofing in years to come, displacing traditional solar modules on rooftops, for two reasons: they produce about the same amount of power and, unlike those modules, they are installed flush with roofing shingles or tiles. For a roofer, that equates to a more straightforward installation.
Currently, BIPV tiles and shingles are installed by solar consultants and qualified electricians to ensure the shingles are wired correctly to invertors. But experts say there is no reason why roofers can't install BIPVs with the supervision of electricians. MARK CUGLIETTA, director of projects at Conergy and a solar photovoltaic design consultant, suggests roofers start familiarizing themselves with the innovative tiles and shingles.
Conergy has been involved in the installation of solar tiles on three homes in Edmonton. Made by GE Energy, the 1.5-foot by 5-foot PV tiles (called Geko) were installed in tandem with concrete roof tiles, says Cuglietta. "We have, surprisingly, seen some growth in this industry in Alberta." He says it "is a bit shocking" considering there are no government grants or incentive programs for solar roof installations and power is "relatively cheap."
The tiles, which fit neatly into the profile of the concrete tiles, cost little more than conventional solar modules that protrude above the roofline, says Cuglietta. An average-sized solar tile roof producing about 2,500 watts of power will cost a homeowner about $23,000. Geko tiles come with a 25-year power warranty, but he believes they should last up to 40 years.
Solar roofs are not economical in Canada, partly because electricity is cheap, making it unprofitable to sell power produced by solar back to the utility company. In Germany and Japan, however, where electricity is expensive and government grants are available, solar roofs are not uncommon.
States such as California are also solar-friendly. California-based Open Energy Corp., a PV tile manufacturer, recently supplied its tiles for a NetZero home in Red Deer, Alberta. Composed of a glass laminate with a silicon cell secured to a polycarbonate frame, each PV tile is simply screwed down in four places to the roof battens. The bulk of the roof is made up of concrete tiles. To allow for expansion and contraction resulting from changes in temperature, some concrete tiles are left floating (unnailed), says TIM SCHULHAUSER, photovoltaic technician at Sedmek Inc. and solar consultant of the job.
The grid of solar tiles is wired, normally in series, to an invertor where direct electrical current produced is converted to alternating current. The invertor matches the phase, voltage and frequency of the grid and the power is then directed into the home's electrical panel, he explains. Typically, a block of solar tiles or shingles is installed on the south facing pitch and covers less than 50 per cent of the total roof area.
Called the Avalon Discovery Three, the Red Deer home is being built by Avalon Master Builder as a NetZero home through Canada Mortgage and Housing Corporation's EQuilibrium sustainable housing program. The photovoltaic tiles used on the Avalon are three-feet by one-foot and come with pre-wired leads. Each tile generates 34 watts of electricity on sunny days. That's enough to power two compact fluorescent light bulbs, says Schulhauser.
DAVE KELLY, also of Sedmek, says roofers should be aware that a BIPV roof will take two to three times longer to put up than conventional roofing.
While photovoltaic modules have been around for 50 years, solar tiles and shingles are new to the market. Solar tiles cost slightly more than traditional solar modules, but they can produce up to half a home's annual power requirements.
Some observers believe that the market for PV panels, shingles and tiles will remain, at best, a niche market for at least another five years or until product prices drop and subsidies on the cost of electricity are lifted.
Given these conditions, could solar roofs take off in Canada? Schulhauser thinks so, provided that the federal and provincial governments offer grants and incentive programs for homeowners and builders. "It is happening in other countries. I think it will eventually happen here."
But solar tile and shingle manufacturers have a big hurdle yet: convincing the market their products are as good as conventional solar modules. ANDREW PRIDE, vice president of the Minto Green Team of Minto Development Inc., says the developer chose the conventional product over BIPVs for its NetZero home in Ottawa because photovoltaic shingles and tiles haven't stood the test of time. One of his concerns is how well the tiles or shingles will shed snow buildup. Conventional solar panels melt snow through heat they generate. "It's possible that they will work wonderfully well, but we wanted to go with something that was known to be reliable."