September 14, 2008
Companies Sell Photovoltaic Roof Shingles
The idea of building solar photovoltaic shingles has been dreamed about for a long time. Installation of the roof would amount to installation of the PV with little added effort. But attempts to achieve commercial success in this endeavor haven't succeeded commercially so far. Now a couple of companies have teamed up to sell thin film photovoltaic shingles.
In an effort to promote the adoption of solar technology, United Solar Ovonic of Auburn Hills, MI, has teamed with a major roofing company to create a metal roof system that generates electricity from sunlight. The partnership offers seven different prefabricated systems, ranging in capacity from 3 to 120 kilowatts. Tests show that the solar roof panels are rugged and can withstand winds in excess of 160 miles per hour.
The article does not mention cost as compared to other approaches. But in theory this approach ought to be able to hit lower price points since it reduces materials needs and simplifies installation.
They claim the pay-back can be as low as 10 years. That's probably in California which has both high electric power prices and lots of sun. In Washington state with cheap hydro power and a whole lot less sun the economics are probably pretty abysmal.
Centria designs and assembles the solar roof systems using United Solar's adhesive thin films, which can simply be peeled off of their backings and stuck to the roofing materials. The company then distributes the final product through small metal-roofing manufacturers that do the installations for building owners and architects. EnergyPeak comes with a 20-year warranty and, depending on the state in which the solar roof is installed, could pay for itself in less than 10 years, Centria says.
The trend in solar has been toward large PV and concentrating solar power facilities out in deserts. Home PV doesn't capture economies of scale that the big facilities can achieve. But some day PV shingles will become cheap enough that they'll become standard on most new housing construction.
Good metal roofs are warrantied for perhaps 50 years; If these photovoltaic metal roofs are only guaranteed for ten, and expected to last 20, then a price comparison based on a standard metal roof is illegitimate.
warrantied 20 years, repay themselves 10years. what metal roof does that?
Photovoltaic roof shingles are a non-event for any hurricane or other re-occurring natural disaster area (e.g.Mid-west Twisters).
The economics of PV shingles v. standard roof + solar panels will sort itself out. No need to worry about facts.
I expect PV shingles (I prefer the word tiles) will be chosen for high-end or custom homes; they look nicer than solar panels. And appearance trumps money in the homes of the rich. And PV shingles will be less subject to wind or other natural damage.
OTOH should PV shingles fail they will be more expensive to replace or repair than panels. And, face facts, solar collection is going to become a lot more efficient. That means today's panels, even if they still work, will be replaced with upgrades in a decade of so. Upgrades will be made for appearance, or less area, or more power from the same area.
Ten year old cars work too, yet they get replaced if the owner has enough money.
For economic return I wouldn't touch solar for a couple more years. But we are not the mindless rational robots that economists imagine as minimizing every cost. Personal satisfaction is important too.
The warranty is probably for the PV part of the roof. I doubt that putting the PV on the metal will shorten the useful life of a metal roof. So after 20 years you recoat the metal with newer PV. Though probably you will want to do that in 10 years because 10 years from now the efficiency of conversion will have doubled.
In Germany the power companies have to buy, at an inflated price, electricity generated from renewable sources for twenty years. Why are we not all doing the same?
In the United States we have at least 2 forms (are there more) of solar power market intervention from governments in the US:
1) Tax credits.
2) Renewable energy requirements put on electric power utilities by state governments.
We pay either way, just by different routes.
Germany's formula for subsidizing solar electric is pretty dumb. The cost paid is (if memory serves) 46 cents/kwh or maybe 46 euro pennies per kwh. That's hugely expensive.
Now the year is 2010,in September.Some pictures I have seen show indivudal solar shingles that are nailed down like asphalt shingles.each shingle requires a small hole to be drilled and has an electric wire lead that goes through the hole.On the Demo video that I watched Bob Villa assisted the installer who blended in 6 or 12 of these PV tiles into a roof that was being installed.The wires from each tile were collected into a junction box,tied together and I believe run to a battery.From the battery there was an inverter to change the D.C. current into A.C. and an outlet box designed to receive 110 volt plugs from "small" devices like battery chargers for laptops or flashlight batteries.
the video said about Five dolars a watt($5/watt) for the shingles.Also said in an southwest PV installation where many more shingles were used it cost about $14,000 or fourteen thousand dollars for 2000 watts.