$this->bbcode_second_pass_quote('Dezakin', '
')
I know a little bit. I suspect we're closer to peak oil than the USGS believes but not as close as next year... Though I would not be shocked if we hit it within five.
One thing I do believe is that if peak oil hits tomarrow, we're all going to be substantially poorer for a little while. My argument is that it will only be for a little while, on the order of a few years to maybe a little over a decade.
PeakOil is You
can we still reach for the stars?
by trespam » Thu 24 Feb 2005, 01:57:36
I looked at the references on Uranium. There is nothing shockingly new to me there. One estimate of 50 years supply AT CURRENT RATES OF CONSUMPTION. Then there are a bunch of guestimates that are largely worthless because (a) they don't take into account the cost of extracting the uranium in energy terms and (b) the rate at which uranium can be extracted.
Goodstein calculates how many reactors would be required in order to replace even a fraction of the energy consumed in fossil fuels. 20% of energy in the US is generated by Nuclear. Let's say we double that. How long will the uranium last then? How fast can be extract it? How fast can be build reactors? How will we fund the development of these reactors when we can't even afford to balance our national budget?
I think your estimates of peak oil are probably accurate--say in five years. With a long plateau after that--efficiency, less driving, economic recession, synthetic fuels (e.g. coal) will help us cost along for a while. Perhaps a long while. But we're going to be a lot poorer. Our monetary system is reliant on growth. Growth will become much more difficult when energy is much dearer.
I'm not a doom and gloom head to the hills type. I think we'll muddle through for a long-time. But economic dislocation is going to be significant as energy prices increase in the coming years.
I think Nuclear will help. And Coal synthesis. With some mass transportation, and other efficiencies, I think we'll be muddling along well beyond 2020. But the standard of living will be on a downward trend.
See Oil, Jihad, and Destiny. It's got similar predictions. We start muddling sometime around 2010/2015/2020 depending on whether we can keep the middle east stable. Then we start on a downhill path unless something fills the gap--coal, nuclear, etc will slow the decline, but I think we will still decline.
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trespam - Tar Sands
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by Dezakin » Thu 24 Feb 2005, 06:14:56
trespam: $this->bbcode_second_pass_quote('', 'I') looked at the references on Uranium. There is nothing shockingly new to me there. One estimate of 50 years supply AT CURRENT RATES OF CONSUMPTION.
Sure. For the current known high grade ore bodies of which have uranium recoverable at todays price. I've had this discussion more times than I can count. There is no exploration for other high grade ore bodies now because uranium is too cheap to be worth it. Moreover, the uranium avaliable at twice the price is about ten times that, and this is in the once through cycle. A breeder reactor cycle extends the life of the ore body 100 fold, cuts the waste stream 100 fold, and is 100 times less price sensitive to fuel costs... and is about 200 times more efficient in terms of EROEI that people seem so obsessed about... no enrichment costs.
So if we're willing to pay twice the price of uranium and we're willing to use breeder reactors, we're looking at 5000 years 'at current rates of consumption'
Then there is thorium, roughly 3 times as plentiful as uranium avaliable... add that into the mix and you're looking at 20000 years worth of fuel 'at current rates of consumption'
At 10 times the price of current uranium prices, recovery from seawater is economically viable... and breeder reactor fuel cycles you are so fuel price insensitve that you wouldn't even notice the jump. Theres enough uranium in seawater for millions of years at current rates of consumption.
$this->bbcode_second_pass_quote('', 'T')hen there are a bunch of guestimates that are largely worthless because (a) they don't take into account the cost of extracting the uranium in energy terms and (b) the rate at which uranium can be extracted.
a) Looking at the cost of uranium mining in energy terms is largely pointless because your energy returned on energy invested is several thousand fold in high and medium grade ores, despite what the popular EROEI site quotes as about 4. These guesses were made from 60s era assumptions that we had exhausted all high and medium grade ores, were using the once through fuel cycle, and the old gasseous diffusion process, which was about 50x more energy intensive than todays centrufuge enrichment techniques. With a breeder reactor cycle your EROEI jumps 100 fold just because you're using all the fuel and more because you dont have to do enrichment. With molten salt reactors you dont even have to do fuel fabrication.
And the extraction of uranium from seawater has been demonstrated to have a positive EROEI.
b) You can allways ramp up the rate of uranium extraction and thorium extraction. its uniformly distributed throughout the planet.
$this->bbcode_second_pass_quote('', 'G')oodstein calculates how many reactors would be required in order to replace even a fraction of the energy consumed in fossil fuels. 20% of energy in the US is generated by Nuclear. Let's say we double that. How long will the uranium last then?
Well, I'll play fair here, and not distort. Its not 20% of energy... its 20% of electricity. Only 8.4% of us energy is produced by nuclear. Lets say we need to run the entire global economy on nuclear power, and that everyone becomes as energy intensive as the US... under a growth scenario of 2% per year of energy consumption even, which is less than historic global energy consumption growth.
Well for a start, you're also going to have conversion losses for the fuel synthesis plants. lets say they're only 25% efficient, and half our energy goes to fuel synthesis.
Okay first we have to multiply the whole number by 12.5 to reach US energy production. Then you need to double that for the fuel synthesis system losses. Then you need to multiply that by 21 for total global consumption.
Now we're at consuming uranium at 525 times the current rate. Now with the thorium and uranium being burned in breeder reactors and we're willing to pay twice the price for it as we pay today, it only lasts 38 years... but with seawater extraction and low grade ores you're looking at least 100 million years worth of fuel 'at current rates of consumption. when we run the entire world on nuclear energy where everyone consumes as much energy as the average US citizen, we are left with 'only' about 200000 years worth of constant consumption.
Lets add in the growth rate of 2%... lets see, I've forgotten my calculus. The total amount consumed in constant years worth is the integral of x^1.02 between 0 and the number of years... so
x^2.02/2.02 - 1/2.02 = 200000...
x^2.02 = 404001
x= 596 years.
So we have about 600 years worth of nuclear fuel for everyone on the planet in a high growth situation. Surely sometime before we exhaust it all we'll figure out either nuclear fusion and inexpensive solar energy.
Theres the worst case scenario. only 600 years of fuel, where at the end we're consuming energy at 140,000 times the starting consumption rate. Though in all honesty I think just doing raw extrapolation of exponential growth is a naive tool for getting a handle on the limits to growth.
Because really at the end the waste heat being pumped into the environment is 1000 times the solar flux. We'd be baked in our own waste heat if we ran reactors that fast. Lets say we can peak out at half the solar flux. That makes it more like 1600 years. Then we only have the lifetime of the sun.
$this->bbcode_second_pass_quote('', 'H')ow fast can be extract it? How fast can be build reactors? How will we fund the development of these reactors when we can't even afford to balance our national budget?
Its all affordable, but that gets into the discussion of economic growth.
In the end we're all malthusians, its just a question of when. My bet is far later than the doomsayers here. The more we learn the further in the future the reckong seems to get.
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Dezakin - Heavy Crude
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). Good luck getting to 200PW!! 
I've seen a few "interesting" waxings on entropy and the second law on this site. 
