I don't work there, I just read some of the popular accounts. I normally take them with a grain of salt, but when they come with pictures of a crew taking a sample of the contents of one of those "sealed" tanks, it's pretty conclusive.
Those tanks are sealed and buried, so I doubt if they are even able to open them up to see if any bacteria is currently living inside.
The tanks cannot be sealed, as many of them are producing gases as radiation breaks down the solvents into free radicals and other molecules. As you recombine CH3- with H+ you get methane, recombine two hydrogen atoms and you get molecular hydrogen, etc. These compounds don't remain in solution and have to be vented off so the tank doesn't explode.
Researchers have to monitor the tanks to make sure that they remain relatively safe. It wouldn't do to have one blow its contents all over the place while we're still gearing up to glassify the stuff, and any plan to process the waste for permanent disposal depends on a detailed knowledge of what's inside.
I don't see how bacteria could survive and grow on energy from radiolysis while their own cytoplasm is being damaged by that same radiolysis.
It is far easier to believe that the bacteria are consuming the organic materials in the radioactive sludge. The Hanford wastes are from the Solvex and Purex processes, which (if I understand correctly) used the different affinities of various ions for organic vs. aqueous solvents to separate uranium and plutonium from fission products. The spent, contaminated solvents wound up in the now-problematic tanks and their continued chemical breakdown under the radiolytic assault is one of the reasons they are so hard to handle.
It does make one wonder: could these bacteria be used to consume the organic matter in the tanks and reduce them to solutions in water? You would have to dilute the waste for the bacteria and re-concentrate the products (say, by evaporation) but getting rid of the organic solvents would be a big plus.
Even at 5%, you'd get 24 KWH out of 100 m^2 of roof under those conditions. If the materials were not much more expensive than conventional roofing it might well be worth it; it all comes down to $/W.
But some differences in quantity become differences in quality. Being able to put cells on a vehicle and get a decent amount of range out of it is enough to tip the balance for many applications. A change from 5% efficiency to 50% does that, and more.
Last, I'll bet that any application using nanocrystals is going to be able to create conformal or maybe even flexible panels. I wouldn't mind having a solar-electric hat to run things while I'm outdoors, or a solar-electric tent fly to power camping gear.
You can burn fissionables in a thermal reactor too; you just avoid including any fertile material in the core. You could do this just as easily with e.g. U-235 or U-233 and some burnable poison (which is depleted as the load of fissionables is replaced by fission product); you would eliminate the fissionables without making any more.
A thermal reactor can be a breeder too, making U-233 from Th-232; IIRC that test was run on the Shippingport reactor before it was decommissioned and found that it would essentially replace its burned fuel and make about 2% more, roughly breaking even.
The average commute is closer to 20 miles/day. Los Angeles is an outlier, but look at the bright side! Even by your calculations you could power a long commute entirely by the solar energy falling on a typical house's roof, and that's without postulating anything other than off-the-shelf batteries and solar panels.
At current rates it makes no sense to try to power one's car 100% by solar electricity, but if you want to make the first 20 miles every day (or every trip) be sun-powered you could do that. Read the EPRI study link off this page (big download, long but informative read). If you did something as simple as putting solar panels over covered parking at workplaces (make covered parking a perk for EV or PIH drivers) you could get a substantial amount of range out of that. If the parking space is 9 feet wide by 17 feet long (roughly 14 square meters), you assume 1000 W/m^2 normal insolation at an angle that gives you 80% of that on a flat surface (probably pessimistic for LA) and 15% efficiency, I get 14 m^2 * 0.8 KW/m^2 * 6 hr * 0.15 ~= 10 KWH/day. At 340 WH/mile you'd get your 20 miles of battery range out of that plus some excess. If you postulate 50% conversion efficiency the production increases to 33.6 KWH/day, roughly 100 miles worth.
If the car is 5.5 feet wide and 15 feet long (roughly 7.5 m^2) and you cover it with 50% efficient cells, given the same assumptions above you would get 18 KWH/day just out of the light falling on the car. If the car used 340 WH/mile you'd get more than 50 miles/day out of the sun falling on the car (the tzero would get ~100 miles). Not so trivial any more, is it?
If your friend is a ChemEng working in petroleum or related areas, I'm sure he could already teach an intro course to gasification including the Texaco gasifier. But if you want a quick pointer, I found this page (try the links for images and other data) or spend some time looking up the Wabash River repowering project (Terre Haute, IN).
The chemistry is pretty simple: C + H2O + O2 -> CO + CO2 + H2 in various ratios. In the applications I've studied, the carbon was in the form of coal or petroleum coke and the gas was subsequently scrubbed of the H2S produced by reduction of pyrites.
If you are trying to produce hydrogen, your carbon emissions will be 100% of the input carbon. However, the carbon comes out as CO2 under high pressure during the scrubbing step; this is easy to capture and can be disposed of in various ways (e.g. into wells) at relatively low cost.
If you're trying to produce lighter fractions from bitumen, I'll bet that the hydrogen is used to turn long-chain hydrocarbons (C50?) into C6-C10 chains. This will require roughly 1 molecule of hydrogen per 6-10 atoms of carbon in the input; if you can produce 2 moles of H2 from 1 mole of carbon into the gasifier, the losses should be relatively low. You'd have the further benefit of having the byproduct heat of the gasifier and oxygen plant to heat the water used to recover the bitumen from the sand (or you could even dissolve the bitumen off the sand using supercritical CO2 as a solvent; you'd have plenty of CO2 available to run the process).
As I am not a petrochemical engineer, I could be missing something about this that makes it completely unrealistic as an approach to the problem. But it looks good from a distance.
Even if you do throttle back, you're going to have to go indoors or swap batteries every few hours. Investing $80 in a nice deep-cycle 12 volt storage battery and a battery box will let you plug into a DC power source outside and run your 'puter all day without having to worry about running out, and you have no shock hazard or installation issues either. Haul the battery in at night and put it on a charger and you should be fine.
I don't know whether it's poor science instruction in the schools or general sloppiness or both, but the vast majority of people I meet (both IRL and on fora such as Slashdot) get this kind of thing terribly wrong. This has costs all around, because people who believe that feasible things won't work will resist them even if they'd benefit, and people who believe that infeasible things are workable will waste their money on frauds, waste their time and energy believing conspiracy theories about the causes (sometimes egged on or even created by demagogues), and cause other problems. My theory is that ignorance is painful, but the ignorant usually can't identify the cause of the hurt so they don't do anything about it.
Anyway, I wanted to address this:
Powering the house, OK. Surplus electricity for an electric car, doubtful. I've yet to see a PV array of compact size that is capable of powering a typical car.
Perhaps you've heard of this amazing technology for storing electrical energy. It's called a "battery", and it's really quite remarkable. You can store energy in them and then carry them around with you to run electric devices a long way from the ultimate source of the energy. It also allows you to use the energy much faster than it was produced.;)
The EPRI did a study which found that a typical small car would require roughly 340 watt-hours of electricity per mile. If you drive 30 miles a day, that would amount to 10.2 KWH/day. If you assume 6 effective hours of sunlight per day, you'd need 1.7 KW(peak) of production to produce it. If you have 1 KW/m^2 of sunlight and panels at 15% efficiency, that's a bit over 10 m^2; hardly a big deal, most apartment buildings have at least that much roof area per unit and detached homes typically have many times that. And yes, you dump the rooftop power into batteries rather than powering the car directly.
There are folks up there also using 'bio diesel', which is basically canola oil + ethanol + an agent to 'crack' the oil (dont ask me what that means, cos I dont know either!) since its cheaper to make diesel then to drive it there.
It isn't cracking, it is an esterification reaction.
Fats (like vegetable oils) are esters of glycerol and fatty acids; as glycerol has 3 hydroxy groups, replacing them all with a fatty acid creates a "triglyceride". In the making of biodiesel, methanol and a catalyst (usually sodium hydroxide) are used to break the bond between the fatty acids and the glycerol backbone, re-forming glycerol (using the -OH radicals) and fatty acid methyl esters (with the -CH3 group of the methanol). The two form separate phases after settling.
If you want to see a real cracking reaction, look at a wood-gas generator (or just watch a fire - the flames are relaxing).
This is usually enough to cover a home's needs (~600kWhrs per day)
More like 25 KWH/day, or ~1 KW average. Running 2 vehicles 25 miles each (50 miles total) at 340 WH/mile would run another 17 KWH. If you got 6 hours of full-sunlight equivalent onto a 100 m^2 roof (~600 KWH of energy) with 15% conversion efficiency, you could get 90 KWH/day out of the roof alone, for about twice what you'd need to run the house and 2 vehicles.
Powering the vehicles and the dark-hours needs of the house requires batteries, which are a different technical problem.
(I'd love to know who modded the parent "overrated", because the moderator is an idiot. This was one of the most informative posts among the +5's when I started browsing this thread, and since I only have time to look at the +5's I would have missed it otherwise.)
The trouble is our tar sands reserves are only about 300 billion barrels and our TOTAL natural gas supplies (which are needed to supply hydrogen so the bitumin can be chemically lightened) are not even sufficient for 10% and North America is already in a Natural Gas crisis.
You can make up for anything with sufficient equipment. The Texaco gasifier is quite able to turn powdered coal or petroleum coke into a syngas of hydrogen and carbon monoxide; the syngas can be shifted to hydrogen and CO2 if you need hydrogen. Since you'd be doing this with methane anyway, the only thing you'd need to add to use bitumen instead of methane for the hydrogen feedstock is to install the gasifier and its air separation plant. The bitumen could probably be sprayed in as a liquid, making the process that much easier than coal handling.
While there is a LOT of energy falling on planet earth and alternate energy forms can yeild a significant source, it is unlikly that these sources combined with reduced wastage can make the kind of difference we need.
I believe that you are correct in the short term, but very wrong in the long term. Natural energy flows on Earth are truly staggering.
In other words, nuclear power is WONDERFUL for the environment; the more radioactivity, the better (within reason at least), because it chases nasty humans out of the area and lets normal plants and animals live in (relative) peace.
You have just described a Viridian Involuntary Park, though if you do it on purpose "involuntary" is no longer true.
The actual size of the waste increases by at least one order of magnitude when we prepare it for cross-country freight.
Are you sure about this? It was my impression that the shipping casks were just that, shipping casks.
I would wonder if it's possible to build the disposal system into the plant.
The US taxpayer paid for the development of a system to create disposal-ready packages of radwaste at reactor sites (mostly the fission products, not the uranium). It is called pyroprocessing, and it was to be part of the Integral Fast Reactor. The process involved electrolytically dissolving the spent fuel in a molten salt bath (no water), plating out the useful elements and leaving the rest dissolved in the salt. The spent salt would be adsorbed into the pores of a zeolite (making it insoluble), putting the cold salt powder into stainless steel cans, hydraulically pressing the cans to solidify the powder and then encasing the cans in ceramic.
The purpose was to build a proliferation-proof breeder reactor, with the fuel so highly radioactive at all stages that it would be impossible to remove it from the "hot cell" areas around the reactor proper. The only thing that would ever leave the reactor would have been the processed radwaste. However, this scheme can be used in a somewhat modified form to process and separate UO2-based PWR fuel as well. The advantage is that there are no organic solvents or water-based chemistry involved, so the problems evident at Hanford become impossible.
The US taxpayer paid for this, but nobody will be benefitting from it; the anti-nukes have succeeded in killing any consideration with a well-orchestrated scare campaign.
To be realistic, this sort of metering should be generation costs only.
Why? Power backfed at the customer site can be sold to another customer on the same distribution line. The utility isn't losing anything. Besides, if you demand that the utility be granted all the benefits of the customer's generation you guarantee underinvestment by the customer no matter how much sense it makes to the system as a whole.
Although it sounds fine, it really is a problem for the power companies; retail rates not only include generation costs, but the huge effort that goes on in transmission and load balancing.
The utility has to ship less power, so their line and transformer losses go down. For solar PV, the afternoon production is a good match to the A/C demand curve so the utility needs less investment in peaking generators and gets higher ROI overall.
Besides, solar PV is such a small factor that we don't need to worry about these things for a while. When it grows to be 10% of peak grid generation it will be, but that time is years away and we have plenty of time to plan.
Just because he doesn't fit the profile of the average consumer does not mean that he is not a general consumer; he doesn't have any billing arrangements that are not available to everyone else.
Imagine your car operating for a week on a one hour solar charge stored in a device the size of 4 D sized batteries.
Let's see, if you drive 250 miles a week and get 25 MPG, that's 10 gallons of gasoline or about 60 pounds. Gasoline has about 9 times the energy of combustion as TNT (because TNT carries its own oxygen). So: Imagine the energy of several hundred pounds of high explosive in a device the size of 4 D-size batteries. Not so appealing any more, is it?
If you want to fix the size of the nanocrystals, precipitate them using wet chemistry; nucleate a whole bunch of them all at once, and they will stop growing when the materials are depleted from the solution. Taking the suspension of nanocrystals and assembling them into a working device is another matter.
It's my understanding that amorphous cells degrade fastest, polycrystalline cells degrade more slowly, and single-crystal cells very slowly. The output curve levels off after a while; single-crystal panels will still be going at a large fraction of their rated output after 25 years unless you hit them with enough heat or moisture to damage them in some way, such as by degrading the interconnects.
The real issue with solar energy isn't watts/m^2 of panel, but watts/$. We have more than enough square footage to power our houses and businesses even at current efficiencies, but the capacity is still so expensive that it is very marginal. If Pb/Se nanodots can be made more cheaply than the same wattage of silicon, we'll be ahead; otherwise we won't be.
If we get really lucky, this technology will work well at high light flux and high temperatures (~100 C). This would allow use of concentrating collectors and use of the waste heat for space heat and domestic hot water, multiplying the benefit of the collector and making the whole affair much more economical. Imagine a house that powers its own appliances, stores enough hot water for several days of hot showers and its own heating load, and on sunny days has plenty of juice left over to feed to electric cars. This house would be almost completely independent of fossil fuels and offset fuel use elsewhere, and I'll bet that we could build it now if cost was no object - if we can get 50% or even 40% efficient solar cells at $2/watt working at 100 C, we'll be there.
Here. Have twenty nickels, buy a clue.
on
Solar Cells Get Boost
·
· Score: 2, Interesting
There's at least one user in California who got on a time-of-day net-metering rate program and installed a bunch of solar panels on his garage roof. His panels are cranking out watts during all of the high-rate hours (afternoon), and he gets credited at the retail rate. At night he charges his electric truck off the grid, and pays for those KWH at the off-peak rate. It's win/win; his panels pay for themselves, and the utility needs less peaking capacity.
This page claims the following (without data on the level of burnup):
238 Pu (1%)
239 Pu (58%)
240 Pu (27%)
241 Pu (9%)
242 Pu (5%)
Note that bomb-grade plutonium is greater than 93% Pu-239 and less than 7% of the other problematic isotopes. There are several pages claiming that bombs could be made from reactor-grade plutonium, but they would require very sophisticated implosion mechanisms. The radiation from the other isotopes would make them difficult to fabricate, increase the cooling requirements and make the material (in or out of a bomb) much easier to detect.
Slashdot Mirror
I don't work there, I just read some of the popular accounts. I normally take them with a grain of salt, but when they come with pictures of a crew taking a sample of the contents of one of those "sealed" tanks, it's pretty conclusive.
Researchers have to monitor the tanks to make sure that they remain relatively safe. It wouldn't do to have one blow its contents all over the place while we're still gearing up to glassify the stuff, and any plan to process the waste for permanent disposal depends on a detailed knowledge of what's inside.
It is far easier to believe that the bacteria are consuming the organic materials in the radioactive sludge. The Hanford wastes are from the Solvex and Purex processes, which (if I understand correctly) used the different affinities of various ions for organic vs. aqueous solvents to separate uranium and plutonium from fission products. The spent, contaminated solvents wound up in the now-problematic tanks and their continued chemical breakdown under the radiolytic assault is one of the reasons they are so hard to handle.
It does make one wonder: could these bacteria be used to consume the organic matter in the tanks and reduce them to solutions in water? You would have to dilute the waste for the bacteria and re-concentrate the products (say, by evaporation) but getting rid of the organic solvents would be a big plus.
But some differences in quantity become differences in quality. Being able to put cells on a vehicle and get a decent amount of range out of it is enough to tip the balance for many applications. A change from 5% efficiency to 50% does that, and more.
Last, I'll bet that any application using nanocrystals is going to be able to create conformal or maybe even flexible panels. I wouldn't mind having a solar-electric hat to run things while I'm outdoors, or a solar-electric tent fly to power camping gear.
You can burn fissionables in a thermal reactor too; you just avoid including any fertile material in the core. You could do this just as easily with e.g. U-235 or U-233 and some burnable poison (which is depleted as the load of fissionables is replaced by fission product); you would eliminate the fissionables without making any more.
A thermal reactor can be a breeder too, making U-233 from Th-232; IIRC that test was run on the Shippingport reactor before it was decommissioned and found that it would essentially replace its burned fuel and make about 2% more, roughly breaking even.
You don't need a fast reactor unless you are breeding plutonium; you can burn Pu in anything that will accept MOX.
At current rates it makes no sense to try to power one's car 100% by solar electricity, but if you want to make the first 20 miles every day (or every trip) be sun-powered you could do that. Read the EPRI study link off this page (big download, long but informative read). If you did something as simple as putting solar panels over covered parking at workplaces (make covered parking a perk for EV or PIH drivers) you could get a substantial amount of range out of that. If the parking space is 9 feet wide by 17 feet long (roughly 14 square meters), you assume 1000 W/m^2 normal insolation at an angle that gives you 80% of that on a flat surface (probably pessimistic for LA) and 15% efficiency, I get 14 m^2 * 0.8 KW/m^2 * 6 hr * 0.15 ~= 10 KWH/day. At 340 WH/mile you'd get your 20 miles of battery range out of that plus some excess. If you postulate 50% conversion efficiency the production increases to 33.6 KWH/day, roughly 100 miles worth.
If the car is 5.5 feet wide and 15 feet long (roughly 7.5 m^2) and you cover it with 50% efficient cells, given the same assumptions above you would get 18 KWH/day just out of the light falling on the car. If the car used 340 WH/mile you'd get more than 50 miles/day out of the sun falling on the car (the tzero would get ~100 miles). Not so trivial any more, is it?
The chemistry is pretty simple: C + H2O + O2 -> CO + CO2 + H2 in various ratios. In the applications I've studied, the carbon was in the form of coal or petroleum coke and the gas was subsequently scrubbed of the H2S produced by reduction of pyrites.
If you are trying to produce hydrogen, your carbon emissions will be 100% of the input carbon. However, the carbon comes out as CO2 under high pressure during the scrubbing step; this is easy to capture and can be disposed of in various ways (e.g. into wells) at relatively low cost.
If you're trying to produce lighter fractions from bitumen, I'll bet that the hydrogen is used to turn long-chain hydrocarbons (C50?) into C6-C10 chains. This will require roughly 1 molecule of hydrogen per 6-10 atoms of carbon in the input; if you can produce 2 moles of H2 from 1 mole of carbon into the gasifier, the losses should be relatively low. You'd have the further benefit of having the byproduct heat of the gasifier and oxygen plant to heat the water used to recover the bitumen from the sand (or you could even dissolve the bitumen off the sand using supercritical CO2 as a solvent; you'd have plenty of CO2 available to run the process).
As I am not a petrochemical engineer, I could be missing something about this that makes it completely unrealistic as an approach to the problem. But it looks good from a distance.
Even if you do throttle back, you're going to have to go indoors or swap batteries every few hours. Investing $80 in a nice deep-cycle 12 volt storage battery and a battery box will let you plug into a DC power source outside and run your 'puter all day without having to worry about running out, and you have no shock hazard or installation issues either. Haul the battery in at night and put it on a charger and you should be fine.
The subject line is the info
Anyway, I wanted to address this:
Perhaps you've heard of this amazing technology for storing electrical energy. It's called a "battery", and it's really quite remarkable. You can store energy in them and then carry them around with you to run electric devices a long way from the ultimate source of the energy. It also allows you to use the energy much faster than it was produced.The EPRI did a study which found that a typical small car would require roughly 340 watt-hours of electricity per mile. If you drive 30 miles a day, that would amount to 10.2 KWH/day. If you assume 6 effective hours of sunlight per day, you'd need 1.7 KW(peak) of production to produce it. If you have 1 KW/m^2 of sunlight and panels at 15% efficiency, that's a bit over 10 m^2; hardly a big deal, most apartment buildings have at least that much roof area per unit and detached homes typically have many times that. And yes, you dump the rooftop power into batteries rather than powering the car directly.
Fats (like vegetable oils) are esters of glycerol and fatty acids; as glycerol has 3 hydroxy groups, replacing them all with a fatty acid creates a "triglyceride". In the making of biodiesel, methanol and a catalyst (usually sodium hydroxide) are used to break the bond between the fatty acids and the glycerol backbone, re-forming glycerol (using the -OH radicals) and fatty acid methyl esters (with the -CH3 group of the methanol). The two form separate phases after settling.
If you want to see a real cracking reaction, look at a wood-gas generator (or just watch a fire - the flames are relaxing).
Powering the vehicles and the dark-hours needs of the house requires batteries, which are a different technical problem.
The purpose was to build a proliferation-proof breeder reactor, with the fuel so highly radioactive at all stages that it would be impossible to remove it from the "hot cell" areas around the reactor proper. The only thing that would ever leave the reactor would have been the processed radwaste. However, this scheme can be used in a somewhat modified form to process and separate UO2-based PWR fuel as well. The advantage is that there are no organic solvents or water-based chemistry involved, so the problems evident at Hanford become impossible.
The US taxpayer paid for this, but nobody will be benefitting from it; the anti-nukes have succeeded in killing any consideration with a well-orchestrated scare campaign.
See, there really ARE environmentalists for nuclear power!
Besides, solar PV is such a small factor that we don't need to worry about these things for a while. When it grows to be 10% of peak grid generation it will be, but that time is years away and we have plenty of time to plan.
Just because he doesn't fit the profile of the average consumer does not mean that he is not a general consumer; he doesn't have any billing arrangements that are not available to everyone else.
If you want to fix the size of the nanocrystals, precipitate them using wet chemistry; nucleate a whole bunch of them all at once, and they will stop growing when the materials are depleted from the solution. Taking the suspension of nanocrystals and assembling them into a working device is another matter.
It's my understanding that amorphous cells degrade fastest, polycrystalline cells degrade more slowly, and single-crystal cells very slowly. The output curve levels off after a while; single-crystal panels will still be going at a large fraction of their rated output after 25 years unless you hit them with enough heat or moisture to damage them in some way, such as by degrading the interconnects.
If we get really lucky, this technology will work well at high light flux and high temperatures (~100 C). This would allow use of concentrating collectors and use of the waste heat for space heat and domestic hot water, multiplying the benefit of the collector and making the whole affair much more economical. Imagine a house that powers its own appliances, stores enough hot water for several days of hot showers and its own heating load, and on sunny days has plenty of juice left over to feed to electric cars. This house would be almost completely independent of fossil fuels and offset fuel use elsewhere, and I'll bet that we could build it now if cost was no object - if we can get 50% or even 40% efficient solar cells at $2/watt working at 100 C, we'll be there.
There's at least one user in California who got on a time-of-day net-metering rate program and installed a bunch of solar panels on his garage roof. His panels are cranking out watts during all of the high-rate hours (afternoon), and he gets credited at the retail rate. At night he charges his electric truck off the grid, and pays for those KWH at the off-peak rate. It's win/win; his panels pay for themselves, and the utility needs less peaking capacity.
- 238 Pu (1%)
- 239 Pu (58%)
- 240 Pu (27%)
- 241 Pu (9%)
- 242 Pu (5%)
Note that bomb-grade plutonium is greater than 93% Pu-239 and less than 7% of the other problematic isotopes. There are several pages claiming that bombs could be made from reactor-grade plutonium, but they would require very sophisticated implosion mechanisms. The radiation from the other isotopes would make them difficult to fabricate, increase the cooling requirements and make the material (in or out of a bomb) much easier to detect.