It’s an interesting discussion. He’s not arguing with my numbers. I’m not arguing with his. Both of us support deployment of nuclear and renewable technologies.
The disagreement appears to be based on whether the land use issue for solar is even an issue.
The context knife cuts both ways on that one.
Naam puts the land use required for a solar United States in the context of the area of the whole United States, coming to a figure of 0.6 %.
This figure is low because Naam uses (as did I) average electricity output per unit land for a system with no storage. It was suitable for my comparison of one facility with another. It is not suitable in a comparison of powering the entire US. In that case, average output and no storage is irrelevant. The worst possible period of output will govern the size and economics of the solar thermal requirements. As Naam says he doesn’t believe 100 % solar is going to happen. Nonetheless, it pays to understand this as many commentators expect a big role from solar with storage.
In the same article, Naam reminds the reader that agriculture roughly uses 30 % of the land of the United States, the built environment is using 166 % of the area that would be required for solar and coal mines are using about the same area as would be required for solar (an interesting quantification, to be sure, which I won’t dispute). National defence areas are raised as another example, and one could go on and on.
There is a serious flaw in this reasoning.
The point was never that the world is literally too small for solar. The point was that land is scarce in the economic definition of the word: it is subject to many competing uses and demands and it must be allocated efficiently. The use that most often gets shafted in our human civilisation is biodiversity. Put another way, we get amazing biodiversity outcomes when we make land near-valueless to humans for anything else. For example Naam highlights disused farm land in the US to assert that the size required for solar is relatively small. The interesting question, surely, is what should we do with this disused land? Give it over to energy production of some form like energy cropping? I would hope not. I would hope it might be returned to habitat as has been the case for New England forests.
Lurching from one land-intensive energy supply to another does not further the land-sparing outcome. The way coal consumes country is horrible as I pointed out in this video. Naam asserts that solar uses the same amount of space, with lesser disturbance. I regard that as faint praise.
Solar thermal won’t work on just any old land. Naam acknowledges that the efficiencies of the system matter. A first-order consideration for economic output from solar is the right area with the best solar resource.
That’s why Ivanpah is in the Mojave Desert, where it displaced an endangered species, not on disused farmland in the eastern United States. Naam’s quantification that a solar USA would require half the Mojave is getting closer to the point. That’s also the reasons why it is on a flat area, not the mountainous Mojave terrain which is much of the terrain. Again, the suitable area is constrained and the relative pressure rises for scarce space.
Pointing out the other (often destructive) ways humans have used land, and the amazing scale of this use, is an argument for constraining our footprint in everything we do from here: agriculture, human habitat and energy to name the big three. Leveraging it to say “therefore this impact doesn’t matter”, well… that’s the sort of corporate, environmental impact assessment logic which time and time again drives the death of a thousand cuts of one area after the next. When an option for massively smaller disturbance is available, as there is in the comparison of nuclear with solar thermal, we should take it. To assert the difference doesn’t matter is a blind spot.