Green Tech Media
I Was Wrong About the Limits of Solar. PV Is Becoming Dirt Cheap
by David Keith
Although quite upbeat about solar PV (and I'm also a big fan of solar PV), this article generated almost 300 comments because it was also frank about the limits of solar PV, and wind, and to make matters worse, he concluded the article with the following statement:
My view is that only two forms of energy -- solar and nuclear power -- can plausibly supply tens of terawatts without a huge environmental impact.This is tantamount to blasphemy in most green (whatever exactly that means) technology websites. Which explains much of the action in the comment field but one comment in particular by Susan Kraemer caught my attention. She feels that CSP (concentrated solar power) with molten salt for heat storage is the answer to solar intermittency. I found this interesting because she had recently written an article at Earth Techling titled How a Hotter Climate Destroys Thermal Electricity Generation. CSP is thermal electricity generation (spins turbines with hot gases and must dump waste heat). The irony (is that the right word?) is that I had explained this to her in a comment under her article:
Thermal power simply becomes less efficient. It will be no more "destroyed" than solar photo voltaic:...you can lead a horse to water.
"As part of Power System Program of the International Energy Agency (EIA), a study was conducted to analyze data from 18 grid connected PV plants located on different geographic locations and it showed a direct relation between temperature and PV module efficiency. The plants were located in Austria, German, Italy, Japan and Switzerland. The study concluded that 17 out of the 18 systems showed annual losses in efficiency due to temperature changes by 1.7% to 11.3%."
Also, solar thermal power plants have the same efficiency loss as any other thermal power source.
So, that leaves wind. Nobody is planning to run civilization only on wind. The future will be some mix of wind, solar, hydro, and nuclear with just enough natural gas to stitch them all together. The fact that higher temperatures will reduce efficiency is just something engineers will compensate for, and the lower efficiency would, all things being equal, result in higher prices, but I suspect the price difference will be negligible.
But the the study she wrote about also pointed out that hydro, the undisputed king of renewable energy, is going to be in a world of hurt. There are a lot of environmental bloggers out there without any kind of engineering background who write about energy issues, and the fact that they don't always understand the engineering principles behind what they write is obvious, at least to an engineer.
VOX
VOX doesn't allow comment under its articles. I try to make it a policy not to provide links for (or usually even read) articles without comment fields under them. Comment fields go a long way to keep blog authors honest. Would you buy stuff on Amazon from a retailer that does not allow reviews of their products? Me either. Why should you have to buy what an author says without seeing what reviewers think? I'm making an exception in this case because I'm essentially providing a comment field for these articles and anyone is welcome to participate.
Two articles by Dave Roberts caught my attention.
