To no one's surprise, the New York Times prefers Barack Obama's energy policies to those of John McCain. I have no quarrel with that, of course. But I would like to nit pick one little phrase in its editorial of Oct. 11, the one in which both candidates are positively reviewed for their inclusion of nuclear power in an energy portfolio of the future. While I could go on again at length about the inadequacies of generating electricity from uranium decay, this time I'll just focus on to little words: "carbon neutral."
The editorialist wrote "Both candidates agree that because nuclear power is carbon-neutral it has to be part of any serious effort to reduce global warming." I'm not aware that either Obama or McCain have ever explicitly stated that carbon neutrality is a reason not to reject expansion of the industry, but even if they have, we have to take a close look at that claim.
And the closer we look, the shakier it gets. We don't have to conduct exhaustive cradle-to-grave analyses of the process of exploring for, mining, milling and transporting uranium to know that nuclear power can't actually be carbon neutral. Not unless all the mobile machinery involved is fueled by biodiesel and everything else draws electricity from solar arrays or wind farms. That's just blindingly obvious. And then there's the power-plant construction process, involving as it does enormous amounts of concrete, and the CO2 emissions associated with that particular building material
But a look at some of the studies that have been by professionals and published in peer-reviewed journals confirms just how far from neutral we're talking about.
One of the more recent appeared this past April in Environmental Science & Technology. In Sustainability of Uranium Mining and Milling: Toward Quantifying Resources and Eco-Efficiency, Gavin Mudd and Mark Diesendorf, Australian researchers at the Institute for Monash University and the University of New South Wales, try to get a grip on the kind of impact just the mining process has on nuclear power's environmental impact. They conclude, and again we are not too surprised, that it depends on how the mining is carried out.
Some mines require a lot more energy, and therefore produce more CO2 emissions, to get at the uranium oxide they're seeking. The quality of the ore also has a big effect on much energy is required at the milling stage to turn it into usable fuel pellets.
Here are the essentials: Since the advent of the first nuclear power plant six decades ago, the world's mining industries have produced about 2.25 megatonnes of uranium oxide. Doesn't sound like much, but there are only 439 or so reactors in operation today and they don't go through uranium too quickly, which is why proponents of the technology think it's such a great idea.
But consider that mining each tonne or uranium oxide can generate as much as 400 tonnes of CO2. The higher grade the ore, the lower the associated emissions, of course. In fact, it can be as low as 10 or 20 tonnes of CO2 per tonne of uranium oxide. The point is, it varies enormously and even in the best case, there is simply no way to honestly round hundreds of million of tonnes of CO2 down to zero. Which is what carbon neutrality would require.
More worrisome is the logical conclusion that average ore grade quality is unlikely to rise as the mining life cycle plays out. It will fall, as it does with every ore, until it drops below some point below which it no longer makes economic sense to dig. So nuclear power is only going to be farther and farther from carbon neutral as time goes on.
Let's kill this little meme while we have the chance. Before the new president starts signing executive orders.
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Gavin M. Mudd, Mark Diesendorf (2008). Sustainability of Uranium Mining and Milling: Toward Quantifying Resources and Eco-Efficiency Environmental Science & Technology, 42 (7), 2624-2630 DOI: 10.1021/es702249v
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You can make nuclear power carbon-neutral. Just use a part of its electricity to capture and store carbon. Possibly using it to synthesize methane.
This is plain silly. 1 ton UO2 is basically one ton U metal, which in a light-water reactor (LWR) (the most common kind) is the thermal energy equivalent of - what, ten thousand tons of coal?
http://en.wikipedia.org/wiki/Energy_density#Energy_density_in_energy_st…
So that max. 400 tons of CO2 from UO2 mining displaces some 14,000 tons of coal, which when burned will emit 51,000 tons (reasoning, coal is mostly carbon, and each gram C goes to 44/12 g CO2.) Less than 1% - and that's using the highest numbers mentioned. I'm implicitly assuming the thermodynamic efficiencies of conversion are the same, which is reasonable.
Of course, the whole premise of this analysis is wrong to begin with! The major resource consumption of nuclear power is not raw fuel: nuclear reactors are extremely energy efficient on a mass basis - as I pointed out, even current-generation, non-breeding, thermal reactors use four orders of magnitude less fuel than coal. If you want to look at the lifecycle energy consumption, you will need to look at the power plants themselves: the hundreds of tons of steel and concrete, the manufacturing costs of sophisticated equipment, etc. Good luck!
While it's not the full resource consumption, I think it's fair to point out that nuclear reactors consume an order of magnitude less steel and concrete than wind turbines:
http://www.nuc.berkeley.edu/news/CEC/CEC_Nuclear_Wksp_Slides_PFP_8=05.p…
(slide 4)
And one more observation: the whole validity of lifecycle carbon emissions is based on the premise that the CO2 intensity of the energy sources is constant. This is only useful at the margin: in the macro picture, if the carbon intensity of the entire economy goes down, then the lifecycle emissions of most processes will go down. Basically, clean energy runs the raw manufacturing processes that are used... to create more clean energy capacity. So yes, I'm also challenging the validity of the very question we're asking.
addendum: The blog's database server is very ill, it is giving me an error message during comment preview.
Well, by that standard nothing is carbon-neutral. Not even sailing ships because, by golly, they are made of wood which will eventually rot away, releasing carbon into the atmosphere.
Ok, so that's a bad example - obviously the boat hull is not made out of fossil fuel.
But the power tools that shaped it and the power looms that made the canvas sail probably did use some.
Point is - when you drag absolutely everything into a "total cost", ultimately it takes the whole of our civilisation to build a modern sailboat. The problem is that this is double-counting.
Yes, the processes to mine uranium (or anything) currently use a lot of fossil fuel. But they don't nessesarily have to - the day someone works out how to make an efficient engine that doesn't rely on pertoleum. The uranium-to-power process does not in itself produce carbon. It just produces radioactive slag that we have to store safely for millions of years, or all get cancer and die.
My personal dream is that someone will invent some sort of substrate which, when you run carbonated water over it will use sunlight to generate booze far more efficiently than chlorophyll does (I mean, think about how many chemical reactions are involved in making ethanol from sunlight, via sugar-cane). Then we can pave the outback with the stuff and what ethanol we don't drink, we can sell. We'll all be as rich as arabs, forever.
Uranium ore must also be transported via most likely diesel truck or cargo ship to the processing plant and then to the reactor. I don't know of any reactor situated next to the mining site. Even if that were the case, would the waste then be left at the site? Probably not. So that too would have to be trucked or shipped out.
Man, I hope people read the comments, because, as has already been pointed out, this post is way off base. Nothing can be 100% carbon neutral. You can see this even for biofuels, supposedly the very definition of carbon neutral. Nuclear power is extremely high bang for your carbon buck, over the lifetime of a plant, plain and simple.
I think y'all are missing the point. It is theoretically possible for some forms of electricity generation to be carbon neutral, so long as the energy used in building it is generated cleanly. That's practically impossible for most sources now, but nuclear poses particular challenges because we're talking about mining and refining ore, which at the moment can only be done with fossil-fuel inputs.
Solar and wind and geothermal aren't carbon neutral either, but it takes a lot less imagination to see how they could approach carbon neutrality. Their parts can be made from recycled materials, for example.
"nuclear poses particular challenges"
I disagree. The sheer volume of solar panels and wind turbines that have to be erected, connected and maintained, along with the creation of all the support buildings, batteries, trenching and other infrastructure required to replace current fossil fuel production is enormous, and, with so many many installations, would require a tremendous amount of ongoing maintenance - lots of vehicles, lots of people, constant repairs, etc, etc, etc.
There's a pretty freakin' huge amount of CO2 involved in that power production as well, if you want to compare apples to apples.
And there's also the cost of building and erecting these devices. And given how many orders of magnitude more of them you'd have to create, you'd only be able to make a tiny fraction from recycled materials - windmills aren't made of aluminum cans, and high-efficiency solar panels will require all sorts of novel components.
On one hand, we have the ability to reduce electricity-related carbon emissions by 90% using well-known technology that is proven to work (nuclear power). This is even before we consider the potential of breeder reactors and other, even more efficient technologically advanced reactor designs.
On the other hand, we have the theoretical idea of generating electricity from as-yet-undefined massive solar and wind farms, using unknown technology, at an unknown cost, with an unknown CO2 footprint from all the infrastructure and maintenance.
Which one do you support? The second one. Sounds more like the "Island of Credulity" to me.
As some others have already posted here, the arguments in the original post are shaky. I mostly really enjoy your blog, and even if I agree with your sentiment, your stated reasons for being against nuclear power don't fly. The peripheral CO2 problem is exactly the same for all the other viable alternative energies, and for most of them it is worse. Semiconductor plants are far worse for the environment than people realize. I guess people think that solar cells are created magically?
Stupid liberals are against anything that remotely smells of common sense. That's why they are against nukes. But all for chasing windmills.