Rather than hijack another thread, I thought we could start another thread since people seem to want to discuss it.
I read the South Koreans achieved a stable 100 million degree plasma for 20 seconds. That's double what they could do last year. If they achieve the same doubling of sustained plasma for 20 years that will be a full year of continuous operation. I think that is viable. Heck, if they can sustain operation for a few hours each day that may well be adequate depending on t he economics (10 years from now). That is what it all come down to, the ec onomics. That's what is killing fission reactors today, the cost, not safe ty issues.
The only reason renewable energy sources are being installed at such a clip is because they are the most affordable source of energy. Once we have ac hieved similar advances in energy storage the sky will be the limit for sol ar. The power utilities will turn into power storage utilities by storing and distributing the excess energy we all create on our rooftops.
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Rick C.
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There are other opportunities where NO residences are involved. E.g., most of our parking lots are slowly being covered with panels. In addition to the power generated, they also provide shade for the vehicles that would otherwise bake in the sun (requiring more cooling load to compensate for the accumulated heat).
And, of course, solar farms in places where no one lives!
(I suspect one in 6 homes in our neighborhood has gone the solar route).
and distributing the excess energy we all create on our rooftops. \
Of course. You need to have very limited thinking ability to believe the i dea that people living in apartments means solar energy is not viable. I b elieve I read once that the roads in the US occupy 1% of the land mass (may have been limited to the 48 contiguous states). That's a huge fraction. I can't find a number for building coverage, but using 66 million acres of "developed" land and 15% efficiency gives some 40,063,878,581.76 kW. Of co urse that's a large over estimate, but I think 40 TW leaves a lot of room f or derating. Currently the US has 1.2 TW total electrical generation capa city. So mark that up by 5x to account for time the sun or wind is not ava ilable and it's still only 6 TW. It will take a lot of batteries.
It is pretty amazing that it is entirely practical for individuals to own t heir power generation capacity and not rely on the grid for other than very unusual conditions. At some point in the future I can see everyone having their own vanadium batteries in the garage to store the solar energy they need from day to day. I haven't seen financial numbers, but it is entirely possible they will allow a week of energy storage to consist of modestly s ized batteries with significantly larger storage tanks tucked into part of the basement or garage. New homes may have them stored in the attic.
Done this way, we may see (well someone, not likely me) utilities as we kno w them become dinosaurs. Buy your electricity from the power company or ma ke your own at a fraction of the cost.
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Rick C.
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Depends of the latitude at which you are living. At higher latitudes when heating of houses is required, reducing the wind speed by wind turbines will also reduce the heat loss from houses :-),
At cloud free areas, the ground daily illumination is about 300 W/sq m and assuming 15 % panel efficiency, you could get about 50 W/sq m daily average power. Find out the electric consumption in your area and calculate the amount of ground/roof space required. The space will still be quite modest.
It depends how much 24/7 industries you have in your network. It makes sense to power it with some reliable sources, such as nuclear. Only if you build more nuclear than the 24/7 industry needs, you may face dispatchability issues as in France.
Instead of storing one form of electricity and making inefficient conversions, just make when you need it. If you have hydro plants, use solar during the day and hydro during the night. Alternatively use fast starting gas turbines and diesels to generate electricity during the night or during cloudy or windless days. Burn some renewables and if you are not an alarmist you cold also use fossil gas or oil during a few hours during the day.
The reason that nuclear power plants are so huge is that is hard to get a reactor licensed. The paper work required by a small reactor is nearly as big as for a large reactor, so build a larger one and save on total amount of paperwork.
One problem with nuclear power is that is mainly (or exclusively) is used for electricity production. This means that high temperatures and pressures are required, also requiring tons of low enrichment nuclear fuel is needed. This means that an active security system is needed (to handle the heat after an emergency shutdown), which is suspicious. For this reasons nuclear sites should not be built near large population centers, It also makes it uneconomical to use it for district heating, due to the large distances.
Smaller units intended for district heating only could be built without an active security cooling system, so these could be built closer to population centers and simplify district heating.
One reason for tons of radioactive spent fuels is the few nuclear powers who in the past insisted that low enrichment grade fuel could only be used in civile reactors in fear of more countries acquiring nuclear bombs. Now that most of those countries wanting an atomic bomb already have acquired one, what is the point of limiting the enrichment of nuclear fuel for civil reactors ? This would also reduce the amount of spent fuel that needs to be stored.
On Monday, December 28, 2020 at 9:27:33 PM UTC+11, snipped-for-privacy@downunder.com w rote:
ic pet projects says it all. What's killing nuclear energy is politicians w ho couldn't care less about anything except their own political careers,
energy is that it is more expensive than renewable sources, and not all tha t dispatchable either.
hen the sun isn't shining, solar power is cheaper than nuclear, you can buy it in much smaller chunks, and there's no waste disposal problem once the fuel is spent. All this is much too complicated for John Doe to process, so he calls everybody else idiotic because they haven't made the idiotic mist akes which underlie his opinion.
Batteries and pumped storage deliver about 85% of the energy deposited in t hem. That's pretty efficient.
Dumping even more CO2 in the atmosphere isn't a good idea, even if the foss il carbon extraction industry is keen on it.
ssil gas or oil during a few hours during the day.
As few as possible. If you aren't alarmed by anthropogenic global warming, you aren't paying enough attention. Australians had a horror bush-fire seas on last year, and more and worse wouldn't be good idea.
reactor licensed.
It's one of the reasons.
ge reactor, so build a larger one and save on total amount of paperwork.
It's probably not economically significant. The fact that the process of ge tting permissions takes ages is probably more relevant.
d for electricity production. This means that high temperatures and pressures are required, also requiring tons of low enrichment nuclear fuel is needed. This means that an active security system is needed (to handle the heat after an emergency shutdown), which is suspicious.
"Suspicious"?
centers, It also makes it uneconomical to use it for district heating, due to the large distances.
Dropping a hydrogen bomb on a nuclear reactor would spread enough radioacti ve contamination to wipe out a small country. Putting them anywhere where the power they generate is close enough to be useful is a bad idea.
an active security cooling system, so these could be built closer to popul ation centers and simplify district heating.
And make life ever so much easier for terrorists.
powers who in the past insisted that low enrichment grade fuel could only be used in civil reactors in fear of more countries acquiring nuclear bombs.
The waste is generated by the fuel burnt. How enriched the fuel was before it was burnt doesn't come into it.
ired one, what is the point of limiting the enrichment of nuclear fuel for civil reactors ? This would also reduce the amount of spent fuel that need s to be stored.
Spent fuel is processed to separate out the longer lived isotopes which do need long term storage. The short-lived stuff is very radioactive and has t o be stored even more carefully, but for all that long. It's the fission pr oducts that create the problem, and that is a direct result of the energy r eleased - the enrichment of the fuel burnt doesn't come into it.
In the spent fuel rods, there is a lot inactive material that does not require extreme treatment. That amount is larger if the original fuel rods contained low grade uranium, thus requiring a larger storage volume for spent fuel.
How many countries have spent fuel processing facilities ?
Even after the normal 30 year on-site storage, reprocessing is still quite nasty due to the high radioactivity of the spent fuel.
Why not do the preprocessing instead by separating U235 from U238 before including the fissile material into new fuel rods. Those two isotopes are quite harmless and easier to process,
Wartime use of weapons doesn't have centuries timescale, and airburst use of a big bomb is destructive enough for any military purpose; only a hate group with nukes would try to contaminate a national entity. Airburst detonation might flatten a reactor, but wouldn't spread the contents.
cquired one, what is the point of limiting the enrichment of nuclear fuel f or civil reactors ? This would also reduce the amount of spent fuel that ne eds to be stored.
do need long term storage. The short-lived stuff is very radioactive and ha s to be stored even more carefully, but for all that long. It's the fission products that create the problem, and that is a direct result of the energ y released - the enrichment of the fuel burnt doesn't come into it.
Quite a few.
formatting link
USA, Russia, the UK, France, China, Israel, India and Pakistan have all go t nuclear weapons and spent fuel processing plants. Germany, Italy, Japan a nd Belgium show up on the list. North Korea doesn't but proibably has the c apacity.
Pure U235 may be fairly harmless in small lumps, but it is radioactive with a half-life of 703.8 million years. The nominal spherical critical mass fo r an untampered U235 nuclear weapon is 56 kilograms, so large lumps are any thing but harmless.
Post-processing is still necessary no matter how enriched the fuel was to s tart with, and the point remains that the amount of stuff that gives you pr oblems is dictated by amount of fission that took place.
One of the advantages of electric power (e.g., for heating instead of natural gas, coal or oil) is that you can move it to places where it is abundant/generated to places where it is needed, relatively easily. No need for trucks, pipelines, etc.
Hard to imagine much solar generation in a place like NYC. But, its relatively easy to imagine generation upstate with a cable delivering it to The City.
Here, it is relatively common for homes to be exclusively powered by alternative means (typ solar) as many folks are too far "out" for an economical hookup to The Grid.
IMO, a more productive option is enhancing energy efficiency. I am dismayed by how little below grade construction is employed, here. Instead, everything sits *up*, in the overbearing sunshine while
*active* mea$ure$ (refrigeration) are used in an attempt to combat the heat soak.
Heat extracted from residences is just vented to the atmosphere. Why not diverted to heat a pool/spa?
Similarly, all of that incident solar energy on panels generates heat that is detrimental to the panel's efficiency. Why not harvest it?
(there's a firm, here, that carries heat away from the PV array hydraulicly which can be used to fire DHW)
tirsdag den 29. december 2020 kl. 03.14.40 UTC+1 skrev Bill Sloman:
uclear bombs.
fore it was burnt doesn't come into it.
acquired one, what is the point of limiting the enrichment of nuclear fuel for civil reactors ? This would also reduce the amount of spent fuel that needs to be stored.
h do need long term storage. The short-lived stuff is very radioactive and has to be stored even more carefully, but for all that long. It's the fissi on products that create the problem, and that is a direct result of the ene rgy released - the enrichment of the fuel burnt doesn't come into it.
ot nuclear weapons and spent fuel processing plants. Germany, Italy, Japan and Belgium show up on the list. North Korea doesn't but proibably has the capacity.
I'd like to see the numbers on that one. A water heater without a heat pum p would require the circulating fluid to rise to temperatures that would no t help to cool a solar array. They typically don't warm to the full temper ature required for hot water use, but they get a storage tank much of the w ay there, then the incoming water is heated by that before being warmed the rest of the way. My point is to actually cool the array requires a contin ued stream of cool water. I'm not sure how well it would work to combine t he two.
If a heat pump is tossed into the mix, then it might be feasible. I can se e that extracting the heat at a low temperature and returning the solar pan el coolant to as low or a lower temperature than it started while at the sa me time heating the output high enough to complete the heating for domestic hot water use. I know they use heat pumps for hot water heaters these day s. So this might end up being very practical and effective if combined wit h a small heat pump.
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Rick C.
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