amorando wrote:let's not forget in the discussion of what we are going to do when oil runs out that nuclear has not yet resolved the question of waste disposal.
Dezakin wrote:Lets look at the average uranium and thorium in the crust: estimates of uranium I've seen are about 2.5 ppm for the earths crust, and for thorium its about 10 ppm.
If we are only focusing on the continental crust thats .374% of the earths mass, so .00374 * 5.9742 * 10^24, gives you about 2.79 *10^14 metric tons of nuclear fuel
Now you can run a 1 GW reactor on about 1 ton of nuclear fuel per year, and the energy necessary to give everyone on the planet an american lifestile is somewhere between 10 and 100 terawatts... lets say 100 terawatts... so you need about 10^5 tons per year of nuclear fuel.
Dezakin, how about the energy yield of this process? Suppose, for example, that we are going to mine uranium/thorium out of granite. I'm assuming that the granite will have to be cut, lifted, crushed, processed etc. So let's assume that all that work will be done by nuclear generated energy. Do you have an estimate of the EROEI in that case?
Dezakin wrote:But really this is all just for the purpose of argument.
And it may no longer be true to say that there is no safe means of disposing of nuclear waste. I have just read a technical report produced by the Finnish nuclear authority Posiva which, to my untrained eye, looks pretty convincing. The spent fuel is set in cast iron, which is then encased in copper and dropped down a borehole. The borehole is filled with saturated bentonite, a kind of clay. Posiva’s metallurgists suggest that under these conditions the copper barrier would be good for at least a million years.(9)
TrueKaiser wrote:
good point. montequest(just using you as a example because you posted in this topic allot) for example uses eroei as the end all marker for anything, and as we know because of the focus on oil as a energy source oil has the highest erori then anything else. he uses this to rule out the effectiveness of other techs, which if had the same focus as oil might have the same or better eroei, as for which one of the other techs would have this potential if focused on at the same level that oil is today i don't know.
he then backs up his claims by going into the laws of thermodynamics(mainly the second law, which does follow the principals of scientific laws and i am not disputing this). since i have come here all i have seen him post in the new energy forum is either out right dismissal of a new technology citing eroei(though some are rather bad to begin with ex. the space convoys to titan) or the 2nd law of thermodynamics(though admittedly free energy is not true).
When nuclear energy was trotted out, they claimed "it would be so cheap, they wouldn't bother to meter it."
Without government subsidies, it would never have gotten to 18% of our electricity generation. They are getting ready to renew the Price Anderson Act which frees the nuclear industry from having to carry insurance against loss of life and property due to the operation of a nuclear facility. What a sweet deal!
There is no technology, nor will there ever be, that will have the cheapness, energy density, scalablity, EROEI and physical properties of oil upon which we have built our current modern civilization that supports 6.5 billion people, no matter how much you focus on it. There is no techno-fix that can replace a phantom carrying capacity based upon a one-time treasure chest of non-renewable energies and a mindset of infinite growth in a finite world. Get use to the idea. It is not going away.
While I support the development of many renewable systems, I choose to focus on educating people to the limits we are constrained by.
I don't post that much to the Energy Tech forum because I don't see it as an answer, only a treatment of the symptoms, not the disease.
Then it would seem you haven't understood anything I've written. EROEI is not the end all for evaluating energy technologies, but one needs to see some numbers to back up claims of viability. One also needs to see energy density numbers. One also needs to see scalability numbers. One also needs to see enviromental impact and sustainability numbers. ONe person stating in an article that K011 ethanol will be "competitive" with gasoline just doesn't cut it. I want hard science.
There is no technology, nor will there ever be, that will have the cheapness, energy density, scalablity, EROEI and physical properties of oil upon which we have built our current modern civilization that supports 6.5 billion people, no matter how much you focus on it. There is no techno-fix that can replace a phantom carrying capacity based upon a one-time treasure chest of non-renewable energies and a mindset of infinite growth in a finite world. Get use to the idea. It is not going away.
While I support the development of many renewable systems, I choose to focus on educating people to the limits we are constrained by. These are not limits based upon some agenda or ideology, but on 30 years of experience in the natural sciences observing and studying the ecological web of life on this planet.
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