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a buck a watt solar?

2007-12-21 16:41:18.492094+00 by Dan Lyke 11 comments

[ related topics: Cool Technology ]

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#Comment Re: made: 2007-12-21 18:12:21.203118+00 by: meuon

Methinks the convergence of needing a new roof, and affordable solar panels may be in the near future. :) Now all I need is a government research grant to pay for solaring our house and a hydrogen generator/storage/fuel cell system.. and.. and..

#Comment Re: made: 2007-12-21 18:44:08.191671+00 by: Dan Lyke

Don't get too excited, because even if they're around a quarter efficient the back of the envelope (1kW per square meter * .25 efficient * a buck per square foot / about 10 square feet in a square meter) says we're probably talking around twenty five bucks a square foot, and we know nothing about the longevity.

You'll probably also have to install them over a solid roof because the panels don't necessarily nest to create a large waterproof surface.

Personally I've got my eye on a neighborhood nuclear reactor.

#Comment Re: Calculations made: 2007-12-21 22:11:58.985791+00 by: m

I think your back of the envelope comes out to $40/kW of capacity, not $25/sqft. Current cell costs are more on the order of $2500-5000/kW, and about $7500/kW installed.

The current claims just sound way too good to be true. Almost, but not quite, on a par with the "real" 2nd law violation that ostensibly came out of Ireland a couple of months ago.

#Comment Re: made: 2007-12-21 22:27:01.19395+00 by: Dan Lyke

Uh... my numbers are all screwed up, I need to re-think that, but theirs are about $1k/kW ($1/w * 1000). I was figuring you get a kilowatt per square meter real, and 25% efficiency is a high ballpark for cells, so $250/square meter, about $25/square foot (rounding copiously and pulling numbers out of my butt all the way).

That's comparing it to roofing costs.

Yeah, we'll see how many panels they're really willing to supply at $1/kW, and how long a warranty they're willing to put on that...

#Comment Re: made: 2007-12-22 10:41:24.001502+00 by: meuon

Don't worry, I wasn't thinking it'd replace a roof. But, while re-roofing, I might want to make mountings for such things, or allow for them. It'll be this summer if something goes bad, or a couple more years if it holds up well.

Unlike bogus perpetual motion machines, solar power is real, works and can provide useful power levels. Issues are efficiency/cost and storage mediums (and their costs). I'd either like a small emergency system, enough to charge 4 deep cycle batteries (no big deal), or enough to actually sell power back to the power company when I was producing excess. As they currently 'buy' at more than they 'sell' at (this won't last) you theoretically can recoup some of your investment. I need to sit down and do some precise math and scenerio spreadsheets.

#Comment Re: made: 2007-12-23 15:41:16.242739+00 by: m

I was not claiming that solar power is not real or viable. But not at $1/sqft with a 25% conversion efficiency. I would be climbing on my roof now if that were the case. Not just for the dollar savings, but other reasons as well. It was the cost/benefit ratio that I was comparing to the bogus 2nd law violation, not the use of solar power.

#Comment Re: made: 2007-12-23 16:38:28.876456+00 by: TheSHAD0W

A 13KW standby generator runs about $3,000. The same in solar panels would cost $13,000 - but wouldn't burn any fuel. OTOH, it would only generate power for 8-12 hours per day in a sunny location. You'd need that battery system or some other power storage system, which wouldn't double the price but might come close.

Let's see:

Assume 10 hours per day, 70% utilization, that gives approx. 100 KwH per day. Let's also assume 10 cents per KwH, YMMV. $10 per day, $3,650 per year, $25K worth of electricity over 7 years, which would just about cover the cost of the system.

I'd say this technology is just about at the break-even point, depending on how much electricity runs you, and how much maintenance this system will require. It should kick ass in remote locations.

#Comment Re: made: 2007-12-23 20:52:36.492586+00 by: meuon

You need 13kw? (Which a good one, installed properly, is more than that. I've bought and installed a 30kw Generac propane genset before, and the current house has a 3.5kw Generac propane genset). At "idle" our house averages .03 kw/hr. With the oven, stove, heat pump, fridge, etc. all on, the peak is under 2kw/hr. In normal use, some lights, computers, TV about .07kw/hr. You need some extra juice for starting current for appliances, running welders, etc.. but my point is, I think we use a LOT less juice than most people, it's a small house (1300sqft?) with lots of natural light, solar heat load (winter), and passive ventilation (summer). I'll no for sure in a month or two, as we've been watching our power usage a lot because of both new toys (the real-time kw usage monitor) and my new business interest in smart meters, but just based on monthly average electric bills at about .08 per kwh (including base and other fees) of about $60/mth means we use 750kw, or 25kw per day. So a 5kw solar array should be plenty. At a $1 per watt that's $5000, plus batteries and inverters and such for storage, cutovers and such and if I scrounge that's another $5000-7000.

If I can either get a research grant, or given possible future business interests, call it a capital business expense, it might just be do-able out of pocket. Cost effective, maybe. A good investment for home resale: maybe, but doubtful, a good personal 'cause I want to' project: definately.

With upcoming tiered electrical rates, increases, and the ability of smart meters like the Echelon EM-1023 to measure forward and reverse (back to the utility) active and reactive power consumption, I think it'll start to make more sense soon.

#Comment Re: made: 2007-12-24 00:10:05.130429+00 by: TheSHAD0W

The math works out roughly the same, whatever capacity you use; payback in 7 years.

#Comment Re: made: 2007-12-29 15:33:30.011881+00 by: TheSHAD0W


Looks like the technology has the potential for being priced at 30 cents per watt.

#Comment Re: made: 2007-12-29 17:13:42.617032+00 by: Dan Lyke [edit history]

Yeah, I've seen all sorts of people claiming that they can get it down to some ridiculously cheap price per watt, it was the claim that they'd actually manufactured it below a buck a watt that caught me here.

But the other big unknown with this technology is life-span.