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The numbers I have are quite different in some of the issues (I hope you will not know if I am for or against it, I just want to check the numbers).

Regarding CO2 production of a nuclear power station (from mining, installation and functioning) I have read a couple of analysis and the numbers range from 1 to 5 % typically (10% in the  worst-case scenario).

Regarding the reserves of high quality Uranium I understood 100 years at present consumption and with present resources. Doubling productions so that all the planet could have the same level of nuclear would reduce it to 50 years roughly.

The number of nuclear fuel with the left-over of Uranium (plutonium and other low-quality fuel) are too diverse and not too serious enough to be taken into account. Numbers range from 50 to 500 years so a proper analysis should be performed (any serious, no-doubt-about-it input here? it will be wellcomed).

Regarding the needs for primary energy, all analysis show that increasing the renewables and reducing consumption is far enough. Nuclear, coal and hydro kept at present levels, the gas  substituted by wind and sun (the increase of power output also coming from wind) and the consumption reduced by 10-20% would produce a world without any primary energy problems in a cnetury easily.

Another completely different issue is transport and private car. There is absolutely no way that wind and sun can produce the energy for a huge mass transport system (necessary if we forbid the car). This is, if we want to get rid of oil (well at least half so that we have foranother couple of centuries) we need electricity to  run trains or generate hydrogen or power the batteries. In this situation, the only sources we have are nuclear and coal. We would have to multiply the present primary energy output two-fold with mass public system (forbidding the car) and three-fold if we alow th presence of private cars (I take into account the development of China, India, South-America, east Europe and their new fleets of fairly efficient cars).
On the other hand coal and nuclear would be able to do it and for, at least, 50 years (three-fold) to 100 years (two-fold).

These are my numbers. Please if I am wrong in any of these numbers, someone please tell me. It is very important to have the basic numbers right.

I am not defending any option, just numbers.

A pleasure.

I therefore claim to show, not how men think in myths, but how myths operate in men's minds without their being aware of the fact. Levi-Strauss, Claude

by kcurie on Tue Oct 18th, 2005 at 06:01:54 PM EST
It's important to keep straight the difference between "cannot ever supply X" and "cannot supply X at today's prices."

For example, solar photovoltaic electricity could easily provide base and demand load generation--IF you can afford the solar cells and are willing to use up big chunks of desert. So could wind, IF you don't restrict where the turbines are placed and have an adequate network.

The big problem with fossil fuel is the CO2. If a CO2 sequestration program was successful, it could eliminate this problem. So, a practical solution to the global energy crisis is to continue with a mix of fossil and renewable energy, and to develop a CO2 sequestration program to counteract the global climate change problem.

by asdf on Tue Oct 18th, 2005 at 06:32:34 PM EST
[ Parent ]
.. even with high prices. The limits comes from a  question of scale. Doubling the total primary energy with wind means multiplying by factor 100 (or more) the present output of wind energy. This is impossible in the next 15 years. It is a question of building factories, mineral resources, input energy. Not space or price.

Sun is even more impossible since the factor is around 10000 and there is a huge initial investment in energy (you need the solar roof working for seven years to recover the enrgy invested).

So right now they are not possible alternatives for doubling primary energy.

Wind with very high prices and after 20 more years of research and capacity building, it would be possible. Not in the next fifteen years.

At least, this is the number I have. I would love to be wrong, believe me. With huge investment and all the resources available I just can see a 10-fold increase  for the next 15 years in the production of wind. This would be more than enough to cover for gas and oil in primary energy.

Please, any input that would show how to make the 100-fold increase with present technology, please give me a link. I really want to be wrong

A pleasure

I therefore claim to show, not how men think in myths, but how myths operate in men's minds without their being aware of the fact. Levi-Strauss, Claude

by kcurie on Wed Oct 19th, 2005 at 12:33:11 PM EST
[ Parent ]
Me too.  This is bogus.  Japan did a study and found that carbon emissions from nuclear power there were even lower than those from wind power.

You can find an interesting analysis of the dubious claims Friends of the Earth are making at the following site:

http://www.world-nuclear.org/co2&nfc.htm

The paper gives a history of where this claim originated and its basis. Frankly I found the paper somewhat confusing. The argument seems to be this -- it takes energy to produce uranium fuel, primarily required for enrichment. If one assumes coal is used to produce the electricity powering the diffusion plant, a German analysis showed (Table 1) that 38,300 tons of carbon would be emitted annually for a 1300 MWe LWR.

Using 2000 data from DOE (available at their eia.doe.gov website), you can calculate that annual carbon emissions based on 1999 numbers for an equivalent sized coal plant would be 8.6 million metric tons per year. Thus a nuclear fuel cycle under these assumptions would produce .5% of the carbon emissions per year that would be produced from an equivalent coal plant.

For another well-reasoned refutation of that FOE claim from a UN organization, see this pdf:

http://www.iaea.org/OurWork/ST/NE/Pess/assets/03-01708_Rognerspeech.pdf

Now the fun stuff -- from the paper at the above site, the Friends of the Earth evidently argued that low grade uranium will required once we "run out of" high grade uranium ore meaning more energy to produce enriched uranium fuel, thus releasing even more carbon annually. The problem I have with this -- I can't find the FOE paper --  but I can't conceive of a situation where even low grade ores would change this ratio substantially. Even if the grade were 1% of the quality of high grade ore, the annual CO2 emissions would increase the contribution by mining by 100 fold -- from 9100 tons per year (in Table 1) to 910,000 per year -- raising the total from .5% to maybe 1-2%. I don't see how you get from here to there. Moreover, it doesn't make sense that you ever could -- if you did, it would mean you need more coal electricity to produce the uranium than you would get from the uranium itself -- just doesn't make any sense.

The other arguments the Uranium Institute makes in rebuttal are straight-forward -- the electricity to process uranium does not have to come from coal; there are ways to enrich uranium more efficiently, especially using centrifuges; and the requirement to enrich uranium is substantially mitigated if fuel is reprocessed. Moreover, as I argued elsewhere, the availability of high grade ore will expand with more exploration as nuclear power demands more fuel.

by Plan9 on Wed Oct 19th, 2005 at 11:04:15 AM EST
[ Parent ]
...multiplying .5% 100-fold give you 1-2%? It gives me 50%. (Actually, more like 33%, but that's another story)

the annual CO2 emissions would increase the contribution by mining by 100 fold -- from 9100 tons per year (in Table 1) to 910,000 per year -- raising the total from .5% to maybe 1-2%.


A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman
by Carrie (migeru at eurotrib dot com) on Wed Oct 19th, 2005 at 11:17:20 AM EST
[ Parent ]
Thanks for calling this to my attention.  I shouldn't post when in a hurry.

I was referring to the impact it would have on the total contribution from the table. But I agree I got a decimal displaced. Here's the table:
www.world-nuclear.org/co2&nfctab1.htm

Mining and Milling -- 9100 tons
Conversion --           1400 tons
Enrichment --        27200 tons
Fabrication --            600 tons

Total  -- 38300 tons of CO3 per a 1300 Mwe nuclear plant. The comparable number from a 1300 Mwe coal plant is 8,600,000 tons. The ratio is .4%.

If the uranium is low grade -- reduced in grade by a factor of one hundred -- one assumes that means the contribution from mining and milling is increased to 910,000 tons. That makes the total 939,200 tons. The ratio is now 939200/8600000 or 11%. I missed a decimal someplace in my earlier communication, but the point is still valid. Even if you use low grade ore, and you further assume all the energy would come from coal- fired electic plants, these numbers still say the carbon emissions are only 11% of what they would have been had the electricty come from coal. The reason it does not go up in proportion to the grade of the uranium is the contribution from the other steps, especially enrichment, remain unchanged.

by Plan9 on Thu Oct 20th, 2005 at 08:34:00 AM EST
[ Parent ]

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