Are solar cells dirty to make?

Hi. A news item about California debating a law that would put solar cells on millions of homes got me thinking. A long time ago in a debate class the instructor mentioned a cite, which no one could dig up, indicating that the process of making solar cells (photovoltaic ??) was so dirty that moving the U.S. to solar power would be a disaster. The cite was from the '70s, IIRC, and would be quite out of date today, I’m sure. Nevertheless, my question has been thus prompted:

Are photovoltaic cells dirty to make, or cost effective on a large scale?

Please keep this as GQ as possible. (Pleasepleasepleaseplease!!!)

Thanks.

There are some really nasty chemicals that go into the production of semiconductors, but it’s possible to build factories in such a way that you keep all of the nasty stuff under control and don’t just dump it in the nearby river. In fact, EPA regulations have forced the folks who make semiconductors and other electronic things like PCBs and components to really clean up their act in the past few decades. Of course, making a clean factoy costs more than making a dirty factory, so gives the folks overseas who don’t have to worry about the EPA an advantage. Ignoring the economic side of things though, yeah, it’s quite possible to mass produce solar cells and not completely muck up the environment.

It’s the economic side of things that gets you though. Even when solar cells are manufactured in places where they don’t much care if you toss the nasty stuff in the river, the solar cells aren’t cheap enough to compete with other forms of power generation.

Solar cells in the 70’s were ungodly expensive. These days the cost is down to the point where it’s at least in the same ballpark as other forms of energy. There are some folks (mostly rich folks like movie stars) who have converted their houses to solar energy and haven’t gone broke doing it.

Another problem with solar that you didn’t mention is the fact that it doesn’t work so good when the sun isn’t out. This probably isn’t much of a problem for california, but the folks up in washington state are going to be ticked off when they’ve had a week straight of rain and all of their batteries are dead. If the price of oil keeps shooting up, you may see a lot more solar power being used in the next couple of decades, but you’re not going to see it universally accepted througout the US just because of the sunlight issue.

      • Ages ago I read an article that said that in order for a common photovoltaic cell to recover all the energy used in making it, the cell would need to be exposed to direct full sunlight for almost 11 years.
        ~

I was about to ask a question similar to this. Does anyone have a cite (or calculations based on cites) for how long it would take a photovoltaic cell to recover the energy it took to make it in one of the “relatively clean” plants? I’d be perfectly happy with the result if you have to choose some particular city to use in the calculation, but would love to see it for, say, Seattle vs. LA (or, more on point for me, Austin :slight_smile: )

Going digging to see if I can answer my own question…

The National Renewable Energy Lab says the payback is 1-4 years.

http://www.nrel.gov/docs/fy05osti/37322.pdf

If this is too great a hijack, please ignore, but if I understand what I’ve read, the better strategy is not to use solar power to generate electricity, but to use it simply for heating (and cooling, somehow?) - no?

I’m unclear about what push there is for this photovoltaic idea, rather than simply reducing extra demand for electricity, but this perhaps falls outside of GQ -?

Solar cells and panels, like pretty much anything else, are getting better and better. Here’s one that makes 170 watts, pretty powerful. 1-3 years @170 watts seems like a lot of power to manufacture a solar panel, even during daylight hours. Not cheap, either at nearly $800.

Even if it takes more energy to manufacture a photovoltaic cell than it ever produces in its lifetime, it still can be beneficial since the cells can be produced where nuclear power is plentifull and is not legislated out of existence, and used somewhere like California, where building a new nuclear power plant is equivalent to a political suicide.

California is particularly sensitive to envornmental issues and the 2001 experience.

PV production is often greatest when electrical demand is, so PVs are a partial
defense against high peak energyc prices. The peak prices reached ludicrous
proportions, at one point a plant demanded and the gird administration agreed, to pay $3,880 per MW, that would be $3.88 per kilowatt wholesale!

Well, they DO require the blood of gentile children for their manufacture, but…

oh wait…I’m thinking of Passover Matzohs…

Never mind.

Don’t we already have a nationwide power grid that “transports” electrical power?

Unless you’re advocating importing PV cells from France and Japan…

We have a national grid, or rather a interlinked net of regional grids. However tranmission losses make it impractical to send electricity more that ~600 miles.

That’s one reason a hydrogen-based energy system would be so great if it could be done practically and affordably. Gas can be piped nationwide, so energy surpluses could be shipped to energy shortage regions. Another huge plus is that hydrogen could hypothetically make it possible to store large amounts of electrical energy, making intermittent sources like solar and wind much more attractive.

(All of the above presume the solving of enormous technical and engineering challenges, such as building truly efficient fuel cells, and so forth).

You can buy kits for your water heater, that route the incoming water through a solar collector on the roof that preheats the water so you use less electricity/gas to heat the water up. I’ve alos seen houses that have large tanks of water lining one or more of the walls. In the winter time, you drop the outer wall, so that the tanks pick up solar heat during the day, then at night, you close up the outer wall, and the tanks radiate their heat into the house. In the summer time, you reverse this, and its supposed to keep your house cool during the day. Unfortunately, its only practical in certain parts of the world. You couldn’t do it in Alaska, I’m sure.

I’ve read that if you live just a few miles off the grid, its now cheaper to use solar panels for your electrical needs than it is to have powerlines ran to your property.

I would think that with the sort of initiative that CA is talking about, you’d have the panels simply hooked into the grid. If they’re generating more power than the house is using, the meter runs backwards, if they’re not, the house can draw off the grid same as always. Then you don’t need batteries - they can just crank the coal or gas plants up a bit when you get too many clouds.

Unfortunately, proponents of nuclear/fossil fuels and renewable energy make a lot of half-truths and complete fabrications about each other and themselves. The toxic chemicals used in manufacturing photovoltaic panels is one of those, as discussed above. Another is that photovoltaic panels or nuclear energy will decrease dependence on imported oil. It won’t because we don’t use electric, solar or nuclear-fueled cars, yet, and oil is only used to make a small amount of electricity (oil-fueled plants burn the left-over stuff no one else wants).

FYI—

Here are some working papers on the pollution-haven issue. (If that doesn’t work, go here and do a search.)

Incidental information from this site. This is from 2001.

“An energy sink is any substance or
process which consumes significantly
more old energy than it is capable of
delivering new. Corn ethanol under
American Farm economy conditions
is an energy sink because it takes the
energy in three gallons of gasoline to
produce one new gallon of ethanol.
Ethanol today is neither renewable or
sustainable.
Photovoltaic Solar is still an energy
sink because not one net watt hour
of pv solar energy has ever gotten
generated. While the latest of panels
sometimes are able to return more
than their energy used to build them,
they cannot yet amortize most fully
burdened total solar systems.”

I don’t know if this is true or not.