Letters to the Editor
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You just haven't been listening
I always offer constructive advice, and educational content. Not even Descartes could teach rocks.
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... associated with electricity generation ...
Watch out, this statement is a little too carefully worded: "At least 89 percent of air emissions associated with electricity generation could be prevented...".
Does the report address toxic emissions associated solely with solar production? Someone who makes the equipment that PV manufacturers use told me that a big problem is that they use nasty chemicals. That adds to the difficulty of starting a PV manufacturing facility in the U.S. The good news is that there is supposedly some kind of revolution going on, and soon (maybe now) they will be much cleaner.
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No One runs on solar
...must have storage batteries (that need replacing every few years), DC to AC inverters, switches, boxes, gaskets, etc...
Although I'm happily surprised that the ecological "footprint" of the solar cells themselves is much better than I expected, someone's gonna have to drive a series of diesel-powered trucks to deliver them from the factory to the installer to my house.
So what's the TOTAL ecological impact (total cost, "out the door" as they say) of installing and maintaining solar at my residence?
Has such a study been done?
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Electro Robot
... I know Descartes, and you're no Descartes. Snarky is yoru normal. But evidently, that is not the whole bookshelf.
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A couple of caveats
As an environmental reporter, I have studied solar fairly extensively. The figure I hear from industry insiders is that it takes about five years of operation for a typical solar panel to generate enough energy to cover the embedded energy of its manufacture and shipping. Also, the head of a solar manufacturing company in Wales told me that cadmium telluride technology contains carcinogenic material, a significant concern in a product that is supposed to be "clean and green." The expected lifespan of a solar system is 25 years, so it's not unreasonable that five years should be spent working off the energy debt. They can also last beyond that. I think solar is a positive development; let's just be accurate when we talk about it so we know what we're dealing with.
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Some comments
Mike Labonte, Comfortable, and Ecoeek:
The unique aspect of this study is that it looks at emissions, including CO2 and heavy metals.
This is quite different than looking at energy payback. This is important, too; depending on the PV technology it typically comes out from 2 - 5 years which is very good for a product with a 25 year life.
You all might be interested to know that the biggest factor in the energy payback is if the PV has an aluminum frame or not. People like to point out that manufacturing silicon solar cells is very energy intensive. This is true, but because the wafers are extremely thin (less than 200 microns) there is very little silicon in even monocrystalline silicon PV modules (and even less in the less efficient, amorphous silicon variety) and thus this is not the most important factor. Conversely, aluminum frames account for a significant amount of material mass. Aluminum is effectively congealed electricity as the smelting process must be done in electrically heated furnaces. This is the primary reason why Boeing is located in Seattle - proximity to cheap and abundant hydroelectric power. Glass, a significant amount of which is used in nearly all PV modules regardless of technology, also contains a very large amount of embodied energy. Summarizing, I would guess that the glass and aluminum (and their upstream production processes) are actually responsible for the majority of lifetime emissions in a PV module, with the cell technology itself in third place.
By looking at life-cycle emissions, this study goes beyond embodied energy to also capture emissions of toxic substances - such as carcinogenic heavy metals in CdTe technology. This has been a black mark against this particular technology, so it is interesting to see it that actually come out on top in this study; it may use bad stuff, but uses so little of it that it balances out the embodied energy (emissions) of the other technologies.
Mike, your point is well taken, but this study does in fact take into account the emissions generated from manufacturing the panels (and upstream to primary energy and other resource extraction). If it didn't do so, the overall emissions profile for PV would be virtually zero. To your other point, there actually is PV manufacturing in the US, from polysilicon production (the dirtiest part of the process) through ingot growing, cell production, module manufacturing and system assembly. It is true that a lot of this does happen "offshore" but that has a lot more to do with the cost of labor in the US. You can hire about 10 highly motivated, degreed engineers in the Philippines or Malaysia who speak fluent English at (locally) very good wages for the cost of one high school educated union factory worker in the US. Perhaps a bummer, but true. As far as emissions go, certainly toxic and dangerous chemicals are involved in certain steps. However, as the industry on the whole is very sensitive to the fact that they are first and foremost environmentally oriented companies, emission controls and material recycling is strictly employed wherever it is that the plants happen to be located.
Comfortable, the specific PV systems studied were large, ground-mounted powerplant arrays in Europe. The study includes what is known in the biz as the Balance of System (BOS) which includes the inverters (DC to AC conversion), mounting structures, wiring, and so on. While this would come out somewhat differently for a household sized system, likely not dramatically so. Inverters last about 10 years and so are not exactly consumables. The rest of the system basically consists of copper wiring and a couple of disconnect switches, nothing dramatic. You are incorrect about the systems needing battery replacements. There are no batteries used in these powerplant systems, or in the vast majority of home systems. See a previous comment I made. In any event, maintainance is negligible.
Hope this helps clarify some of these issues.
Best,
A solar industry "insider"