Potential of alternative energy sources?

[Dinosaur]

I have seen all sorts of articles about wind turbines, petroleum-like products from corn or some other plant, solar cells, geothermal, et cetera.

I think our government has subsidized quite a few businesses attempting to create such energy sources.

I have never seen any serious article documenting how much energy might be obtained from such sources.

Solar cells seem to have a lot of potential, but I think they are expensive. How cost effective are they? They could be put on roofs witout impacting other uses for the space. It might be possible to have arrays of solar cells floating on the oceans. I suppose some technoolgy could put a lot of solar cells on some orbiting device. Except for coal & nuclear, they might be the only source of alternative energy with potential for producing a significant percentage of our needs.

Wind turbines have been extolled in quite a few articles, but how much power could we get if these devies were expointed to the limits of space available for them?

How much energy could be obtained via ariculturally derived products?

Is any of this technology likely to provide enough energy for our purposes?

I think coal & nuclear power might be the only sources capable of providing a significant percentage of our needs if the petroleum wells run dry.

The potential of coal is the only petroleum alternative I have ever seen touted as providing enough energy to rival what we get from petroleum.

 

[Billy T]

If controlled fusion proves to be either unachievable or unaffordable, eventually mankind will need to live on the energy currently received from the sun. (Fossil fuels are "ancient gifts" from the sun and nuclear fission is an even more ancient gift from other older stars that died to give it to us and others.)

However, I believe that fission can safely supply man's energy needs far into the future. I favor storing the radio-active waste for a decade or so until most of the short live time isotopes have decaded, then making the radioactive residue into glass disks about couple of feet in diameter and few inches thick (exact dimensions will be set to make internal heat not melt them even when only in air). I.e. the internal heat will be transported to surface and at not more than few hundred degrees C hot, transfered to the air. (Can keep in water pool most of the time for less than 100C surface temperature, until ready to transfer to the permanent storage transport ship. -See next paragraph.) The outer few mm of each disk is pure glass to stop any alpha particles inside, but the disk are "leaking gammas" so automatic handling is used.

The disk are loaded onto special ship that have automatic handling to load them into the stern mounted “disk hurlers” that simply toss them into the ocean while ship is traveling slowing over a deep ocean trench. After hitting the ocean they fall for an hour or so to the bottom and in a year or two have fine layer of sediment on them. In 1000 years they are several meters into the bottom dirt. In 100,000 years or so they are an intrusion in some newly forming rocks. In 10 million years or so they are beginning to melt a many kilometers deep in the Earth. In a billion years or so, they may be on their way back up to the surface in some volcanic plume on some new continent, but are no more radioactive than other parts of that plume.

As far as meeting man’s needs for mobile energy, public buses with super flywheels and biofuel cars are the way to go "city scale" distances. Electric trains for longer distances. At present the only biofuel available and affordable is tropical alcohol, usually made from sugar cane collecting and storing solar energy naturally, much more cheaply than any artificial system man has yet designed. Brazil uses approximately 1% of its agricultural land to supply its fleet of alcohol powered cars. (In Brazil alcohol is now more than 50% of all car fuel - it is even more than 20% of what is in the cars buring "gasoline.")

 

[Echo3Romeo]

I always enjoy reading your posts, Billy T.

Vitrification FTW!

 

[krokah]

Processing radioactive wastes the way Billi T describes sounds like a wonderful idea. I wonder if our government has thought about this. I am sure some antinuclear group or greenpeace would disagree.

 

[Nasor]

Processing radioactive wastes the way Billi T describes sounds like a wonderful idea. I wonder if our government has thought about this. I am sure some antinuclear group or greenpeace would disagree.

Of course governments know about it. The main problem is that reprocessing in that way also allows you to get fuel for nuclear weapons, so most western governments don't want the technology to spread around.

 

[Billy T]

Of course governments know about it. The main problem is that reprocessing in that way also allows you to get fuel for nuclear weapons, so most western governments don't want the technology to spread around.

The process I outlined does NOT do any separation of isotopes - why do you think it dangerous?

 

[Carcano]

The disk are loaded onto special ship that have automatic handling to load them into the stern mounted “disk hurlers” that simply toss them into the ocean while ship is traveling slowing over a deep ocean trench. After hitting the ocean they fall for an hour or so to the bottom and in a year or two have fine layer of sediment on them.

Hmm...whats to stop GWB's evil-doers from harvesting the disks from the ocean floor, to use for their own fell purposes?

Can't we just toss the waste into one of those super deep abandoned oil wells in Texas. They are filled with water anyway right?

 

[Carcano]

Gaia theorist James Lovelock says he'd like to have some radioactive waste to store in his backyard pool, to provide heat for his house.

The enviromentalists (who love him dearly) go positively ape...every time they hear that!

 

[Billy T]

Hmm...whats to stop GWB's evil-doers from harvesting the disks from the ocean floor, to use for their own fell purposes?
Can't we just toss the waste into one of those super deep abandoned oil wells in Texas. They are filled with water anyway right?

First of all the ocean trenches are very deep. I am not sure, but bet there are less than four robots in the entire world that can survive the pressure to even move around down there for a few meters.

Secondly the disks would be very hard to find, even by a human walking around down there with powerful search light (It is totally dark of course) even if that were possible. Try dropping a coin in a pool and watch it oscillate side to side. – Thus, even if you had tracked the ship from space and knew exactly its path the disks probably would be spread out in a swath more than a mile wide and immediately covered with thin layer of the sediment they disturbed when hitting the bottom.

Finally, what good would they do you if you found one? - They are a mix of isotopes in glass - containing almost every element that exists. Very very difficult to "un mix" and recover separately any material suitable for making a bomb." Possible perhaps, but at least 1000 times more expensive to “un mix” to get bomb grade plutonium purity from them than from a small reactor designed to make a lot of plutonium fast as was the one that was so badly mismanaged at Chernobyl that it exploded.

When everything is considered it would be more than a million times more expensive to get bomb making material from the deep ocean glass mix of isotopes in the disks, even assuming you could find them, than just make some as N. Korea has been doing.

 

[Carcano]

Ok, but why is your idea any better than storing the disks at Yucca Mountain, which has apparently been declared unsafe...requiring more ground water studies at least ?

What happens if a glass disk is cracked?
Whats the range of its radioactive emissions?

 

[Billy T]

Ok, but why is your idea any better than storing the disks at Yucca Mountain, which has apparently been declared unsafe...requiring more ground water studies at least ?

What happens if a glass disk is cracked?
Whats the range of its radioactive emissions?

Cheaper and puts them out of anyone's reach "forever." In 10,000 years I would not want to drink water from well near Yucca Mountain. In 10,000 years the meaning of the radioactive symbal may no longer be known by the desendents of human kind - they may find the tunnel useful to escape the ice age cold. etc. This dangerous stuff needs to be put out of mankind's possible reach. Deep space would be nice but rockets do explode and are expensive.

If a disk cracked, then some alphas would go about 8 or less inches into the air (much less in water) before becoming helium. There would be gammas going a few feet in water and much further in air (but intensity per square meter falling off as inverse square). I do know know accurately but would guess if they contain only decade or older waste and you stood 10 feet away from the crack, you might get the radiation exposure that an air line pilot gets each month in an hour of standing there.*

It is sort of an academic question as the glass would be quite hot in the core and self annealing continuously. Possibly if dark adapted you might be able to see a faint blue light from them (Cherenkoff radiation) of if you were an pit viper that can see IR radiation even see their heat glow.

Because of their high internal temperature your question is sort of like asking what happens if butter cracks? - I.e. hard to imagine how a crack is even possible.
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*Few people realize it, but the spent fuel rod assembly is not a source of "death rays" (The nuclear reactions are all stopped and the decay alphas and betas cannot get out.) - In fact you could put your hand on it an hour or two after it came from the reactor for a while (ten minutes?) with no noticeable ill effect (assuming it is has cooled down to below 40degrees C - that is about as hot a piece of metal you can touch.) Probably like a 1920s X-ray in exposure I would guess.* - They would not let you touch it unless you were wearing gloves. - They do not want your hand grease on the case. :bugeye:
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*When I was a kid there was a shoe store that had an X-ray machine that looked sort of like one of the scales you could put a penny in to get your weight and fortune; except at foot level you could stick your foot in see** if there was room to wiggle your toes inside the shoes or if a toe was hitting the end or sides. I got more exposure from it I think than you would from a “cracked disk” if it was 10 or more feet from you – but again, I am just guessing.
**I don't know how the optics worked - I just recall seeing my toes and toe bones and the very dark nails of the shoe as grey shaddows on a green screen.

 

[Carcano]

In 10,000 years I would not want to drink water from well near Yucca Mountain.

Very informative post...however, why are you not equally concerned about radioactive material seeping into the ocean as you are about well water?

 

[Echo3Romeo]

In truth, we'll probably have really cheap SSTO or even a space elevator long before the politically motivated 10,000 year mark ever gets here. Then we'll just send it into the sun or something. We only need to sit on this stuff for a few hundred years, after which point it'll only be a hair above background count anyway (still a heavy metal hazard however). Fission is just one of many stopgap measures in the grand scheme of things to get us over the next hill.

 

[Billy T]

Very informative post...however, why are you not equally concerned about radioactive material seeping into the ocean as you are about well water?

Because in 10,000 years (after Yucca Mountain's doors have rusted and crumbled or been by-passed by the people thinking it must guard gold etc.) the glass disks in the Earth far below the deepest oceans (where even today man can not go), would still be containing the isotopes. No curious human would take them to his home (or cave?) because of the weak blue glow. (That happen in Brazil a few years ago - some testing company financially failed and it had a "lead pig" with radioactive material, which a thief stole and sold to scrap dealer who cut the pig up after dark noticed the blue glow and took the powder home to show kids etc. - By time they and some neighbors were very sick a doctor understood what had happened - As I recall, only a few people died, but cancer will claim more as the years go by.)

But let’s ignore that containment in glass matrix and assume the isotopes are separated from their "glass box" and diffusing in the newly forming rocks surrounding them. These "soft rocks" are being transported deeper into the Earth at approximately (or greater?) the diffusion rate.

 

[ElectricFetus]

I beleive cheap nuclear fusion will be possible someday, but for now, earth, fire wind, water, By YOUR powers combined...

Intermittent power sources like solar (fire), wave-tide-current energy (water) and wind can replace maybe 20% of the grid before energy stoage systems are needed like giant Na-S or V redox batteries, bot of which are already in multi-megawatt pilot plant stages.

geothermal is a big option, closed organic and Kalina cycle geothermal plants could suck gigawatts from even low temperature hot rocks, up to 20% of the USA has such rocks in drilling range!

Nuclear waste would be much better utilized in a subcritical reactors, where it would be destroyed and provide power for generations to come. dumping nuclear waste is like dumping gold because you can't find a use for it!

 

[Carcano]

Because in 10,000 years (after Yucca Mountain's doors have rusted and crumbled or been by-passed by the people thinking it must guard gold etc.) the glass disks in the Earth far below the deepest oceans (where even today man can not go), would still be containing the isotopes. No curious human would take them to his home (or cave?) because of the weak blue glow.

Ok, but dont you think Physics will have figured out a way to render waste harmless within the next century?

 

[Billy T]

I beleive cheap nuclear fusion will be possible someday,

Why do yo think it can compete with coal? You know, I assume that coal is only a small fraction of the electric bill (20% or less) and > 80% is capital costs including the distribution. Only hydropower and other solar power is with zero fuel cost but fusions fuel would be smaller fraction of cost than coal. The capital cost of a coal furnace and brick chimney is very small compared to vacuum systems, super-conducting magnets, neutron shielding and avoiding neutron induced radioactivity problems. (The D/T reaction energy release comes out mainly in 17 MeV neutrons, as I recall.) etc.

...geothermal is a big option, closed organic and Kalina cycle geothermal plants could suck gigawatts from even low temperature hot rocks, up to 20% of the USA has such rocks in drilling range!

The efficiency is low, less than 20%, due to the low temperature. Thus you need a lot of cooling water to throw away 4 times more energy in waste heat than you get as useful output. Fresh water
is getting to be in short supply. Not many good geothermal sources near water surpluses and disposing of the salty brine that almost always is the means of extracting the geothermal energy is a problem - reinjection miles away is possible technically (often for good reasons illegal) but in any case expensive in both dollars and energy.

Nuclear waste would be much better utilized in a subcritical reactors, where it would be destroyed and provide power for generations to come. Dumping nuclear waste is like dumping gold because you can't find a use for it!

I do not follow you here. What reaction is there in a "subcritical reactor"? How do you reduce the total radioactivity by running a reactor? - Do you have a reference so I can understand what you are thinking of? Certainly, you can increase the radio-active material by putting non-radioactive material into reactors - many medical isotopes and Co60 are made that way.

 

[Billy T]

Ok, but dont you think Physics will have figured out a way to render waste harmless within the next century?

I doubt it, but so what -the problem is now and I hope growing as we use more nuclear generation for base load power and less fossil fuels.

 

[ElectricFetus]

Why do yo think it can compete with coal? You know, I assume that coal is only a small fraction of the electric bill (20% or less) and > 80% is capital costs including the distribution. Only hydropower and other solar power is with zero fuel cost but fusions fuel would be smaller fraction of cost than coal. The capital cost of a coal furnace and brick chimney is very small compared to vacuum systems, super-conducting magnets, neutron shielding and avoiding neutron induced radioactivity problems. (The D/T reaction energy release comes out mainly in 17 MeV neutrons, as I recall.) etc. The efficiency is low, less than 20%, due to the low temperature. Thus you need a lot of cooling water to throw away 4 times more energy in waste heat than you get as useful output. Fresh water
is getting to be in short supply. Not many good geothermal sources near water surpluses and disposing of the salty brine that almost always is the means of extracting the geothermal energy is a problem - reinjection miles away is possible technically (often for good reasons illegal) but in any case expensive in both dollars and energy.

I do not follow you here. What reaction is there in a "subcritical reactor"? How do you reduce the total radioactivity by running a reactor? - Do you have a reference so I can understand what you are thinking of? Certainly, you can increase the radio-active material by putting non-radioactive material into reactors - many medical isotopes and Co60 are made that way.

Bill,

Look up Bussard reactor, Look up Dense Plasma Focus

Low temp Geothermal plants would be air cooled not water cooled, example: http://www.nrel.gov/geothermal/pdfs/30275.pdf
its a closed cycle system including the geothermal brine which is re-injected.

Look up subcritical reactor

Why is it so hard for everyone to just google phrases they don't understand! If I say something I expect people to google it instead of making idiots of them selves.

 

[Syzygys]

I think coal & nuclear power might be the only sources capable of providing a significant percentage of our needs if the petroleum wells run dry.

I agree but 2 problems arise:

1. Coal beside being dirty, also can and has peaked. In the USA in absolute quantity we still produce more and more coal, but not in relative, calorie value.

2. There is such a thing as peak Uranium, thus we can not just build as many nuclear power stations as we want...