Saturday, April 21, 2018

Photovoltaics? Who in the world would want to spend money on such a silly idea?

The "Solar Roadways" plant in Idaho in an image from the "EmphaseEnergy" site. The performance of this expensive plant is abysmally low and, with the best of good will, I can't see it as anything but a propaganda stunt to denigrate renewable energy. Not the only example of this strategy.

I have to confess to you one of my darkest sins: I read the unnameable blog by Anthony Whatever "What's down with this" and, occasionally, I even enjoy it. Probably, this sin of mine is condemning me to Hell, where I will be punished by having to spend eternity trying to teach thermodynamics to an audience of neoclassical economists.

Sometimes, however, the unnameable blog is worth reading. For instance, in a recent post, Will Eschenbach engages in an all-out attack against the "solar roads" plant in Idaho. The post is appropriately titled, "The Road to Hell is Paved with Solar Panels" and, in it, Mr. Eschenbach criticizes the plant mainly in terms of the cost of the energy produced. He says that it produced 246 kWh in one year. Comparing with the total cost of the plant, said to be more than 4 million dollars, then, clearly, it is a bad deal.

Eschenbach has a point here, although, for fairness, we must note that the plant was never conceived as a commercial plant, it is a prototype or a demonstrator which involved a cost in terms of the development of special panels for a specific task. It is unfair to pretend from a prototype to generate a profit. The question is, rather, is the performance of the prototype good enough to be worth reproducing it at a commercial scale?

Clearly, the people of solar roadways have grand plans. In their site, they speak of paving all the roads in the 48 contiguous states and produce something like 15,847 Billion Kilowatt-hours per year, which is three times the total consumed today. There is a little problem, though: how efficiently could that be done? In their site, nowhere you can find the rated power and the actual performance of the prototype system. But, with some work, we can estimate these parameters.

First if all, they say that they installed 30 panels of 44 W each, The number is confirmed by counting the panels on the pictures of the plant. So, that makes a total rated power of 1.3 kW. Then, the data at tell us that a zero-tilt, 1.3 kW fixed solar plant in Idaho is expected to produce about 1600 kWh/year.

Comparing this result with the 246 kWh reported by Eschenbach, we see that the plant has big problems: it produces less than 20% of what it should produce. There are various reasons that may explain the poor performance of a PV plant. In this case, it seems reasonable to me that a plant located in the middle of a parking lot - with people walking on it - produces much less than a standard plant would do.

So, Eschenbach is correct in noting the poor performance of the plant - nobody would ever want to use these devices for anything more than an expensive toy in a parking lot. But, in the end, that's not so much the point. The point is that the idea of "solar roadways" just makes no sense. Do you really want trucks to run over solar cells? I mean, think about that for two seconds and you can realize how silly the idea is.

This is not the only case I know of badly overpriced and poorly conceived solar plants. In the picture, here, you can see the "solar diamond," another high-cost PV installation built by ENEL in 2009 in Italy. (BTW, it stands close to where I live!)

Maybe you could find this object aesthetically pleasing, but the shape is wrong for a PV plant and its performance is abysmally low. You may also be interested to know that the cost of the whole plant, which includes a fancy hydrogen storage system, was about a million Euros for a total rated power of 13 kW. A better ratio of cost to power than the "solar road" in Idaho and, at least, this one is not supposed to have trucks running on it. But a big waste of money anyway.

So, how come that people engage in these silly ideas? Hard to say, there surely holds the principle that Eschenbach paraphrased in the title of his post "The road to hell is paved with good intentions." But, in addition to that, I can't avoid thinking that the people who promoted the idea and financed these plants did that with the specific idea to pass the message that PV is expensive and useless (*). As usual, propaganda rules the world.

(*) Note: this statement doesn't imply that the people behind the Idaho plant (Scott and Julie Brusaw) are evil or trolls paid by the fossil fuel industry. They may well be true believers in solar roads. Ufortunately, their work is being exploited by the enemies of renewable energy and they are helping to disparage the ideas that they try to promote. Propaganda is an opportunistic beast, extremely dangerous and always hungry.


Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)