Saturday, March 28, 2009

Mojo ain't workin'

It is only my second post, and already it seems clear that I could probably fill this blog with daily entries about the nonsense published.

Mother Jones is a magazine of hard-hitting investigative journalism. So when I added its RSS feed to my Google Reader yesterday, I was surprised to find this article, which claims things about photovoltaics that simply aren't true.

The author is a certain Julia Whitty, and she apparently claimed last year that, "In recent years new photovoltaic technologies have nearly doubled the efficiency of solar cells". Unfortunately, the efficiency -- the amount of sunlight that the cells can actually turn into electricity -- did not change much at all from, say, 2005-2008, at least if we are talking about the polycrystalline and monocrystalline cells that make up around 90 percent of the market. And if we are talking about thin-film cells, then efficiency has increased, though not by nearly 100 percent for any of the technologies.

I can only guess that she is talking about something else, such as perhaps wafer thickness; since the beginning of the millennium, solar wafers have thinned out from 300 to around 180 microns, so perhaps Ms Whitty meant that we can make nearly twice as many cells from the same amount of silicon. But the industry speaks of wafer thickness here, not efficiency.

In her recent article, Ms Whitty harkens back to a long disproven misconception when she writes, "the ratio of energy the panel produces over its useful lifespan compared to the energy required to manufacture it sucks" (her emphasis). Solar panels once faced criticism that it took more power to make them than they ever output. Nowadays, even Wikipedia knows that solar panels, which generally have warranties of 25 years these days and are expected to run longer than that, provide an energy payback within just two or three years. Perhaps that still "sucks" (since Ms Whitty does not tell us what the energy payback is in numbers, we just have to take her at her word), but it's a lot better than the energy payback of roofs without solar, especially the black shingles on most American homes, which heat up the attic considerably in the summer, thereby drastically increasing the need for air-conditioning.

The other misleading claims are more nitpicky -- for instance, the MIT study she refers to does not seem to be in any way the "first," but perhaps Ms Whitty is not aware of the plethora of literature in German on the production processes for solar cells. As someone who translates this material every day, I would agree that the industry sees all kinds of potential ways to streamline production processes. But saying that current efficiency levels "suck" doesn't seem to do the subject justice.

Ms Whitty closes with an admonition: "Take heed bright green environmentalists." One can only hope she will start to get her facts right at some point.

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