Comments on: Solar tiles that offer style

Building-integrated photovoltaics won't make your inner architecture critic wince, but you may have to make a trade-off on efficiency.

[mishmash0101]

50% less efficient? Throw them into the junk pile where they belong and let's move on...

[texaslabrat]

It's short-sighted to look at the overall efficiency on a watts/area basis. You also have to look at dollars/watt and the aesthetic issues as well...and in this area these seem to be competing quite well.

[squished]

Disagree. These have potential given their aesthetics (they're not perfectly out of site but a far cry better than ugly panels) and the other advantages listed at the end by their marketing director. Granted her opinion is biased but her argument makes sense.

[sdf0013]

That's pretty interesting, and especially the time of day effectiviness. Has there been any news story about well any of these things hold up in storms; especially like hail storms.

[Harlan879]

I wonder what the lifetime cost is. That's the cost of the tiles, plus installation, plus the cost of integrating the electricity into the house's power system and the grid, minus the cost of terra cotta tiles (amortized), minus the cost of terra cotta installation (amortized), minus the cost of the offset electricity. (I'm guessing that these will probably have to be replaced before the standard terra cotta tiles will...) Hopefully that number is less than 0, otherwise these aren't ready for prime time yet.

[texaslabrat]

don't forget tax incentives

[Joe Real]

This data is WRONG! Physically impossible. You can't possibly get more than what you put in. Please redo your numbers:

"SRS Energy's statistics say the average homeowner with Solé Power Tiles can get 860 kilowatt hours per square foot annually living in an area with "5.8 peak sun hours" per day."

1 square foot is 0.09290304 square meters. One square meter perpendicular to the sun typically receives 1,000 watts of radiation power. Let us assume that we have 100% conversion efficiency for simplicity's sake:

The total maximum power that you can get for one year from one square foot of area tilted in the optimum way to get 5.8 equivalent direct sunshine hours would be

0.09290304 m2/ft2 x 1000 W/m2 x 5.8 hrs/day x 365.25 days/year x 1kW/1000 watts = 196.81 kWH/ft2/year at 100% conversion efficiency!

AND THEY GOT 860 KWH/sq ft/year!!!

[texaslabrat]

Yep...those numbers are trash...SRS Energy's spokesperson responsible for them needs to lay off the crack pipe.

[fromthedeskof]

It's 860 kwh per SQUARE per year. A SQUARE of roofing material is 100 square feet. So SRS' tiles will produce 860 kwh per year per 100 square feet. I think that significantly less than the total maximum at the optimum conversion rate of 100 percent.

[mherzfeld]

A more accurate estimate may be calculated by knowing the number of photovoltaic source circuits, module specifications, the number of inverters, module orientation, and other things.

Besides, there is a difference between solar modules being used as a "fixture" or "materials" If solar modules are used as "materials" they may at least contribute to the energy requirements. For instance, "no one expects a payback from their conventional roof and it never contributes to the energy needs ..."

Also there is a park lot shown next to the building. Parking structures with the use of conventional Crystalline and Multicrystalline Silicon Modules should be an option. A parking structure may be able to increase the available area an further contribute to the energy requirements of the structure and provide other features.

[ecdfan]

Ok, where to begin?

This story is patently false, and reveals the dangerous ignorance (or intent to deceive) by the Director of Marketing of SRS and the author of this unfortunate article.

1. The tiles efficiency is nowhere near 8% to 10%. The best Unisolar can do on panel level is 6.7%, and only for a portion of their production. Most of the production results in 6.3% efficiency on tile level.

http://ecdfan.blogspot.com/2009/06/unisolar-efficiencies-mystery-of-pvl.html

2. In the real world, there is no advantage that will allow these tiles to get 10 to 15 percent more output in terms of a KWh per KW vs crystalline cells. In fact, given the curvature, they won't be tilted optimally, and thus will generate less electricity per KW than regular crystalline modules. All this talk about waking up earlier,. the light spectrum, etc is a total fabrication. Five documented real-world studies demonstrate beyond a reasonable doubt that the alleged KWH/KW is a myth. See here:

http://ecdfan.blogspot.com/2009/06/thin-film-solar-installation-revisited.html
http://ecdfan.blogspot.com/2009/05/kwhkw-myth-part-iv.html
http://ecdfan.blogspot.com/2009/05/kwhkw-myth-part-iii.html
http://ecdfan.blogspot.com/2009/05/kwhkw-myth-part-ii.html
http://ecdfan.blogspot.com/2009/05/kwhkw-myth-part-i.html

3. Commenter Joe Real is correct. It is physically impossible for modern non-concentrated PV system to generate 860 kilowatt hours per square foot. The SRS tiles will generate just 7 kilowatt hours per square foot on an annual basis (calculated as 5.8 W/sq ft * 1200 KWH/KW), at best, in Pennsylvania. That is 99.2% less than what the author claims.

4. texaslabrat & squished will be disappointed, especially since these things will be twice the cost of regular rooftop PV, will NOT be eligible for incentives (Unisolar-based products are not eligible for incentives in California starting July 1st), and will be a fire hazard. As far as lifetime costs are concerned (to answer commenter Harlan879), those will be horrible (no, the SOLAR tiles will never pay off). The original Unisolar shingles, SHR-17 (now taken off the market), also carried a supposed 20-year, 80%-rated-power warranty, but no longer carry the UL certificartion and were shown to degrade in likely violation of their warranty (and then Unisolar simply stopped disclosing degradation data):

See here:

http://ecdfan.blogspot.com/2009/06/unisolar-eligible-for-incentives-in-ca.html
http://ecdfan.blogspot.com/2009/06/certification-of-safety.html

5. Solar modules obviously cannot be roofing materials (as they cost 10-30x the price of roofing materials per sq ft). The shingles described here are normal shingles with the PV material glued on top of them. Over time, that typically leads to delamination given the different thermal expansion coefficients, and these things will fall apart (become just shingles) well before the 20 years are over. In other words, you pay $35 per sq ft for the solar tiles (just solar tiles, no inverter, installation, etc) before incentives (if any!), and you end up with a $2 per sq ft spanish tile. Not a good prospect!

[texaslabrat]

Thanks for your concern on item #4..but I'm not disappointed at all as they WILL be covered under federal incentives as well as the utility-based incentives for the area in which I live (I'll defer to you on California-specific things but newsflash: California isn't the whole country). I, for one, don't plan on actually purchasing said tiles..but that's beside the point I was making in my prior post. As for "twice the cost"...as I pointed out...aesthetics count for a LOT for many people due to HOA's and the like, and therefore it's short-sighted to discount that from the value equation. There are many places where you simply can't put up traditional solar panels due to HOA regs...but the tiles would definitely be good to go. Perhaps Uni-Solar hasn't had the best rep in the industry thusfar, but you're drawing a pretty far-reaching conclusion on all future products and their performance based on some rather old products in an industry that has had a breathtaking pace of innovation over the past few years. Just sayin'.

[BtmnHatesRbn]

Sign me up. I can use any breaks in my power bill where I live (middle of the Nevada desert).

[mherzfeld]

A more accurate estimate, for instance, a solar site shading analysis tool and software for an accurate solar and shade data estimate - with other various data and the zipcode. Although a rough estimate may derived with the power loss equation for the balance of systems (BOS), should include additional derate factors such as Light Induced Degradation (LID), ...and other factors.

Other mounting options, may including an awning attached to the structure with conventional Crystalline and Multicrystalline Silicon Modules.

[ecdfan]

The blatant and massive marketing fraud perpetrated by the company featured in this article has been exposed here:

http://ecdfan.blogspot.com/2009/06/marketing-of-solar-tile.html

CNET should strengthen their editorial control and issue a retraction.

[dragon_lady_jade]

great looking home, I live in Texas and it has been hot over here. We got a little rain today. I am trying to save engery. in our 3 bedroom home and two bathroom. what more can I do to save more energy. Thank you.

[dragon_lady_jade]

It will not hold when Hail hits.

[dragon_lady_jade]

We all want to save engery, on our homes, and there are things you can do one if you can go to sleep early like around 9.00pm. do everything early when you get up at 5.00am . and only run you're AC when it hit's when it get's to the 80's. that is one way to save money. last month our light bill was $125.00, this month it is $147.00 , also it helps to have celling fan's in you're home .

[nylonnek]

Thank you ecdfan. To underscore everything you said....I looked for product specs and finding none on SRS or US Tiles site I wonder if any exist. I can only assume that since the specs are hidden the hope is the marketing hype will suffice. Likely not.