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October 20, 2005

CO2 Emissions from Nuclear Power Plants.

David Lowry, writing in today’s Guardian, tells us that nuclear power is not in fact free from CO2 emissions and that it is thus not a green alternative.

Thus life-cycle analyses are essential to assess the true impact of the entire processes. A number of such studies have examined CO2 emissions - commonly expressed as CO2 equivalents per kWh - for different methods of producing electricity. The most comprehensive model has been created by the Öko Institut, which advises the German environment ministry, and by Professors Smith and Van Leeuwen at the University of Groningen, in the Netherlands.

Read "most comprehensive" as "the one which proves my point".

Using sensible assumptions, Professors Smith and Van Leeuwen determined that nuclear generation produced about a third as much CO2 per kWh as conventional mid-sized gas-fired electricity generation.

Gosh, really? The reason why this is so depends upon this one highly suspect part of the calculation:

As several papers made clear when presented to the World Nuclear Association's annual symposium last month, the industry will increasingly have to rely on poorer-quality uranium ores, and thus CO2 emissions from the nuclear cycle will increase.

Is this in fact true, that we will in fact have to be using low grade ores? Over to the World Nuclear Association....the people quoted above (yes, I know, an industry body wrote the actual paper but when quoting from "several papers" one might indicate that there is a touch of controversy over the claim?):

Studies of the carbon dioxide emissions from the nuclear fuel cycle under the different circumstances prevailing in two different countries show that these emissions are in the region of 0.5% to 4% of the emissions from the equivalent coal- fired generating capacity.                   Assertions that nuclear power could indirectly produce significant  quantities of CO2 depend on a highly improbable scenario.

They specifically reject the contention that there will need to be a move to low grade ores in the coming decades. It might also be worth noting this:

A review of studies of CO2 emissions from the nuclear fuel cycle has been undertaken. An estimate of CO2 from the CANDU fuel cycle based on actual Canadian experience with mining and refining of uranium ores and separation of heavy water has been presented. An upper bound estimate based on the assumption all energy input comes from high carbon fossil fuels is calculated for comparison.

Over one hundred times as much CO2 is avoided by deployment of the CANDU fuel cycle in place of coal plants in Canada than is released by CANDU construction, the fuel production process, and decommissioning. The electrical energy output per unit of CO2 released overwhelms that from the direct use of fossil fuel for electrical energy.

That latter paper also includes some wonderful numbers on concrete used in different power systems etc. Did you know that wind power uses two times more than nuclear?

Now, some people tell usthat nuclear creates, over the whole cycle, 0.5% to 4% of the CO2 of the equivalent volume of old coal technology. David Lowry tells us that nuclear emits about a third of a gas fired station, basing his idea on his assumption (refuted by others) that there will have to be a move to low grade ores.

No, I don’t know whether 0.5% to 4% of coal emissions is the same as a third of gas fired plant but I’m willing to take a guess.

Mr. Lowry is spouting crap.

(BTW, one might note that if we reduced our emissions by 66% (more if we replace coal with nuclear) by ditching gas fired and having only nuclear then we’d be pretty happy boys really, wouldn’t we?)

October 20, 2005 in Nuclear | Permalink

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Comments

If we're talking "total, lifetime carbon cost" here let's look at the process.

Building a nuclear teakettle vs building a coal fired one. Two thumping great lumps of concrete and metalwork. Some carbon cost, but probably about the same in total and very small in the bigger scheme of things. Nil-nil game so far.

Getting the fuel. This means mining. Uranium fuel rods are quite small compared to the quantities of coal needed, but you need to mine a lot to get enough uranium to make one. Lets be generous to the coal miners and say that kWh for kWh the carbon cost of mining coal and mining uranium is equal. At half time the scores are still level.

Running the power station for thirty years. From my basic knowledge of chemistry and the periodic table uranium is an element with absolutely no connection to carbon. The radioactive decay of uranium cannot, does not and never will release carbon dioxide. Coal on the other hand is carbon. Burning it creates three things aside from heat: Ash, carbon dioxide and, if the furnace isn't working properly, carbon monoxide. Since coal fired stations burn a lot of coal each day this means a lot of ash, CO2 and CO over the thirty years. Late in the second half coal has leapt ahead of nuclear by several hundreds of orders of magnitude.

Finally decommissioning. Breaking up those thumping great lumps of concrete and metalwork.
OK, dismembering an irradiated nuke is likely to be more costly than breaking down a coal fired station. Let's say one hundred times more carbon costly. I'll bet that the total, lifetime carbon cost of coal fired stations is light years ahead of an equivalent nuke.

Final score: Nukes - not much carbon. Coal fired - quite a lot actually.

Can anyone show me otherwise?

RM

Tim adds: Given the amount of thorium in coal there’s probably more radioactivity released by hte coal plant as well.

Posted by: Remittance Man | Oct 20, 2005 12:32:35 PM

I'd like some more specifics on "equivalent coal-fired production". Coal-fired power stations differ wildly in their CO2 efficiency and I suspect that the nuclear industry would not necessarily have chosen the most efficient coal technology as comparator. The Norwegians have said that they mean a "mid-sized" gas station which is a bit better but not much.

Remittance Man: since the actual numbers (0.5%-4%) are given above, what benefit is it to talk about "light years", "a little", "not much" etc here?

Worth noting also that nuclear power stations in general have to be stationed a bit further away from the sorts of places where you actually need the electricity, so I would also prefer to see the comparison made per kw/H consumed rather than produced. (They're also - or at least the ones that I lived next to twenty years ago were - less flexible in their output than gas, which has its own cost; the Dinorwic pump-storage system ought to be counted as part of the carbon cost of the Wylfa and Trawsfynydd nuclear stations).

I do wish that the whole carbon-emissions debate would have a moratorium upon blahing on about power stations for about ten years though. It's pretty plain that while we're all driving round with extremely inefficient small internal combustion engines, we can't pretend we're taking the whole subject seriously just by putting up a few wind farms or whatever.

Posted by: dsquared | Oct 20, 2005 2:13:15 PM

My colleagues David Bradish and Clifton Farrell have done lots of work debunking these projections.

Posted by: Eric McErlain | Oct 20, 2005 2:43:44 PM

Tim,

A couple of months back we at the Nuclear Energy Institute took a good look at these life-cycle emissions claims. Here's a link to a previous blog posted by us and at the end of it is another link addressing uranium supply:

http://neinuclearnotes.blogspot.com/2005/07/nuclear-energy-and-total-life-cycle.html

"Nuclear power plants do not emit criteria pollutants such as SO2 and NOx or greenhouse gases during operations. This is a well known fact, but it hasn't stopped some anti-nuclear groups from making misleading statements regarding nuclear power.

One of the most common claims heard is that nuclear power emits greenhouse gases during its entire life-cycle. This is true, just as it is true of renewable generation..."

Many opponents of nuclear reference the two groups you mentioned above. They are always slamming on nuclear and trying to lump it in the same category as fossil fuels with regards to emissions.

The thing that gets to be annoying is that we never hear of groups performing as much a comprehensive and scrutinous life-cycle emissions study on wind, solar or other "green" technologies. Why? Because the results come out to be pretty much the same as nuclear. And I'll show you.

In the blog I referenced above there's a link to NEI's website to a specific page on life-cycle emissions. There are four tables from four different sources showing life-cycle emissions of most every technology.

http://www.nei.org/index.asp?catnum=2&catid=260

We'll let you guys decide whether our claims are more realistic or the anti's claims.

Posted by: David Bradish | Oct 20, 2005 3:06:23 PM

D2

I'm a strategic planner so talking actual numbers is professional suicide.

Besides it's fun tweaking tails sometimes, no?

RM

Posted by: Remittance Man | Oct 20, 2005 3:18:34 PM

OK, in all seriousness, I should have used the numbers available - bad Remittance Man. But commenting from work with the boss popping in and out of the office all the time doesn't always make for coherent thought.

I'm still convinced nukes are better when it comes to greenhouse gas emmissions which does seem to be the big issue at the moment. As to their other environmental problems, I'll leave that to the experts.

RM

Posted by: Remittance Man | Oct 20, 2005 3:57:34 PM

If CO2 emisson is so low why USA has not put up any power plant based on Nuclear Energy
after 1980?

Is t true that 3000sq. mile area gets destroyed in case of any mistake?

P.J.LAKHAPATE

Posted by: Prakash Lakhapate | Aug 1, 2008 9:17:56 AM