<World Oil Exports [01] Angola The Oil Drum DrumBeat: July 2, 2008>

186 comments on Energy Transitions Past and Future

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mdsolar on July 1, 2008 - 10:00pm Permalink | Subthread | Parent | Comments top

The calculation is pretty easy. A 200 Watt panel weighs about 42 pounds. With 5 hours a day peak equivilent illumination you get about 9 MWh over 25 years, or about 200 kWh per pound. Coal gives about 1 kwh per pound. So, silicon requires much less hauling than coal for the same amount of energy.

If you want to compare to uranium, just figure the distance between you and a panel factory. For me it is about 70 miles. Then consider uranium mined in Australia, enriched in France and used in Maryland together with the shielding needed to transport it and you'll see that silicon also gives more energy than uranium in terms of how much lugging is involved.

I see that the anonymous cowards who have been rating my comment down don't like physics much, but that is really all that is going on here.

CHris

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MCrab on July 2, 2008 - 2:04pm Permalink | Subthread | Parent | Comments top

In 2007, the 439 operating nuclear reactors produced 2608 billion kWh requiring 76,200 tonnes of U3O8.

76,200 tonnes = 167,640,000 lbs

Therefore Energy/mass = 2608e9/1.68e8 = 15,557 kWh/lb

Then consider uranium mined in Australia, enriched in France and used in Maryland together with the shielding needed to transport it

What shielding would that be, Chris? Uranium is a low activity alpha emitter. A sheet of paper would suffice. As for the distances you mention, it is worth again considering how small 76,200 tonnes is. You could easily transport it all with a small fleet of clipper ships!

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mdsolar on July 2, 2008 - 3:31pm Permalink | Subthread | Parent | Comments top

So, if you carry out the math, you'll see that silicon wins. It is not all that important. It just puts the geewizz aspects of fission power into perspective. It ain't that cool. Fusion from a safe distance is much better.

A container for shipping 45 kg plutonium in a MOX assembly weighs 3.9 tonne. http://www.ccnr.org/lyman_casks.html#typ
So, you can call it packaging or shielding but it is a little more extra mass than solar panels ship with.

Chris

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Dezakin on July 2, 2008 - 7:08pm Permalink | Subthread | Parent | Comments top

Could you be any more dishonest? Really, think about your argument here.

1. MOX isn't used for a majority of power plants.
2. Plutonium in mox is about 1% of the fuel load.

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mdsolar on July 2, 2008 - 7:26pm Permalink | Subthread | Parent | Comments top

Worse and worse. I thought the plan was to put reactors down all over the world and reprocess the fuel in nuclear weapons states. You're just walking right into it.

Look, this really isn't important. Getting coal from the mine to the power plant probably reduces its EROEI by a good bit (in fig. 6 the value for coal is mouth-of-the-mine while that for oil is likely delivered), but that is not the case for moving solar panels around or nuclear fuel unless there is an accident. Silicon is superior to uranium by a bit but neither have the problems carbon for combustion has. I have heard of plans to ship uranium ore. That could be stupid I guess.

Chris

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Dezakin on July 2, 2008 - 7:59pm Permalink | Subthread | Parent | Comments top

I thought the plan was to put reactors down all over the world and reprocess the fuel in nuclear weapons states.

I know thats what a lot of people want to do, but I think its just a good way to waste money. Spent fuel doesn't hurt anyone while sitting in dry storage casks in a cordoned off parking lot of the power plant, and should stay there for the next several hundred years. You don't save money by reprocessing and you complicate the fuel cycle. As far as I can tell it has some potential for being a money saver in some fluid fuel reactor regimes, but with operating reactors today theres just no reason to do it except politics.

Silicon is superior to uranium by a bit but neither have the problems carbon for combustion has. I have heard of plans to ship uranium ore. That could be stupid I guess.

Not anymore stupid than shipping coal. All uranium mines today have ores that have higher energy density than coal when burned in LWRs.

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mdsolar on July 4, 2008 - 12:43am Permalink | Subthread | Parent | Comments top

It is worth noting that we've been over some other ground in response to this same article about a year ago: http://www.theoildrum.com/node/2856#comment-224123

The reason for controling spent fuel in non-nuclear weapons states is to avoid proliferation problems. So, on-site storage is not what people have in mind.

Chris

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GRLCowan on July 2, 2008 - 6:14pm Permalink | Subthread | Parent | Comments top

Right. Unenriched uranium yields 54 electrical MWh per kilogram in the plant near me, 24.5 electrical MWh per pound, more than 100 times the supposed 25-year yield of a solar panel, and requires no shielding.

--- G.R.L. Cowan, H2 energy fan 'til ~1996
http://www.eagle.ca/~gcowan/Paper_for_11th_CHC.html

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mdsolar on July 2, 2008 - 7:08pm Permalink | Subthread | Parent | Comments top

I presume you are using a CANDU reactor, and very likely your uranium came from Canada. So, the transportation involved is likely less than typical. What I'm using now was likely mined in the Soviet Union, enriched and down blened there and then transported to the East Coast of the US. That would make lbs miles per kwh about the same as solar not counting packaging. I was thinking more of what to expect in 2013 or so.

Nukulur kooks tend to get all excited about E=mc2 and drool all over fission. This just points out that silicon does E=mc2 with much greater elegance than uranium.

Chris

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MCrab on July 3, 2008 - 1:28pm Permalink | Subthread | Parent | Comments top

Chris, I know you derive particular enjoyment from these mathematical drivebys you like to do against nuclear power, but can't we agree - for the sake of truth and fluffy bunny rabbits - that lbs miles per kWh is a piss poor metric to judge either nuclear or solar. Transport costs are a minor fraction of the EI in their EROEIs. Essentially the whole argument in this thread is a proxy for EROEI and not a very good one at that. Kinda like two men arguing over which is tallest based on who's wearing the thickest socks.

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mdsolar on July 3, 2008 - 2:05pm Permalink | Subthread | Parent | Comments top

I think I've said as much in the thread. It is just fun really. For coal, it does make a difference. Gas also loses something in translation. Oil begins to see some important cost over long distances too.

Chris

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186 comments on Energy Transitions Past and Future

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