Agree. Using surplus renewable energy to make synthetic CH4 from ambient CO2 and water makes a whole lot more sense than making hydrogen from the same surplus renewables and water. Of course, we're a long way from having actual net surplus renewable energy over a significant period of time and geography.
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Nuclear power
- Thread starter eledille
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mspohr
Well-Known Member
Synthetic CH4 is even worse than H2 for storage since you have all of the inefficiencies of H2 generation then add CO2 to get methane. Only about 30%
However, thermal generators do have a benefit: they generate heat as a by-product. Electricity is just one part of energy use. If you want to clean up energy, you'll also want cheap, clean heat. So, if LFTR can both generate electricity and act as a clean heat source, without the large water demands of traditional thermal, it would be useful in locations with significant heating demand. US Power & Marijuana LLC?
But it's much easier to store and transfer. We already do so in enormous quantities.
And you can use the product in many existing electric generating stations or pipe it to homes that can use it for central heating and water heating.
nwdiver
Well-Known Member
Unless you're trying to heat a decent sized lake there are limited applications for that much heat. Of the ~400 nuclear units in the world I don't think a single one uses cogeneration. The thermal plants I've visited don't even use cogeneration onsite. They use electric strip heaters for their people spaces.... it's cheaper.
I'm sure that part of the challenge is siting. If you can't site a thermal plant close to a large consumer of heat you're going to have a problem making use of the heat. And if you need to make thermal plants very large for the econmics to work the problem is exacerbated. If the economics of LFTR allow for simpler, safer, smaller power plants then use of waste heat is likely to be easier, on top of the fact that LFTR would be more efficient than and so produce less waste heat per kWh than a traditional PWR.
As of now the cheapest heat comes from coal and the easiest cheap heat comes from natural gas. If you want to replace them both, you need to come up with an effective, economical alternative for colder climates.
nwdiver
Well-Known Member
True; But often the most obvious source of heat isn't the easiest or cheapest. That misconception has kept the solar thermal industry alive long past its expiration date. Most of the time it's actually cheaper to use PV and a heat pump than to capture the heat directly.
Similarly with nuclear cogeneration. Cold climates tend to have abundant wind resources. The cost of generating electricity from wind power is now ~$0.02/kWh. The heat from cogeneration might be free but the infrastructure and maintenance are not (unlike power lines there are chemistry controls for pipework to transfer heated water). It's unlikely that cogeneration would be cheaper than electrically driven heat pumps. If there were significant advantages it would probably be in wider use.
No doubt there are certain applications where LFTR is far and away the best candidate.... but those niche applications are so few and far between that it's impossible to justify the expense to develop and deploy it. If we're going to spend Billions to bring a new technology to market.... let's get next-generation heat pumps working first....
Skotty
2014 S P85 | 2023 F-150L
I'll have to admit a little ignorance here. Why would a thermal plant have any significant waste heat? Why can't it use most of that heat for the purpose it created the heat for in the first place?
nwdiver
Well-Known Member
The carnot cycle. A steam plant needs to condense steam to function. This means that the maximum thermal efficiency is ~40%. ~33% is the average.
Vogtle operation dates pushed back 6 months (Unit #3) and 3 months (Unit #4):
Vogtle operation dates rescheduled
"We are seeing improvements in productivity and believe this momentum will be maintained"
Always put any news in a positive light.
RT
Vogtle operation dates rescheduled
"We are seeing improvements in productivity and believe this momentum will be maintained"
Always put any news in a positive light.
RT
mspohr
Well-Known Member
Dying robots and failing hope: Fukushima clean-up falters six years after tsunami
Dying robots and failing hope: Fukushima clean-up falters six years after tsunami
Looks like Fukushima cleanup will take a lot longer and cost a lot more (may not be possible at all).
Dying robots and failing hope: Fukushima clean-up falters six years after tsunami
Looks like Fukushima cleanup will take a lot longer and cost a lot more (may not be possible at all).
nwdiver
Well-Known Member
That's kinda disturbing. I can't imagine there's that much radiation from decay... there's got to be active fission still occurring.
Well... if there's a silver lining to all this... we're learning a lot about how to protect electronics from hard radiation. Looks like we've got a bit more to learn. You'd think Space X would be all over this... it would be a great test-bed and great PR if they succeed.
mspohr
Well-Known Member
nwdiver
Well-Known Member
>$200B US with no return....
Imagine how much solar, wind and storage could be built with ~$200B...
Further investment in fission is literally insane. We keep doing pretty much the same thing but expect different results.... it's a bottomless pit of stupidity
Not likely. You need a moderator to slow down the neutrons. The stuff that's causing all the trouble is no longer in the reactor, it's sitting on the floor underneath. It doesn't have any moderator around it.
nwdiver
Well-Known Member
Water is moderating neutrons from the corium.
I don't think the radiation levels they're experiencing are physically possible from decay ~6 years on.
It may not be sustained fission but the short lived isotopes that could provid those elevated levels of radiation would have decayed away by now and the long lived isotopes couldn't possibly be emitting that much radiation.
The scary part is that not much is known about the critical geometry of molten fuel. For obvious reasons there's not a lot of real world testing that's been done on a melted pile of used fuel. It's possible that the geometry of the fuel pile combined with the presence of irradiated fuel has permitted regions to exist where fast fission is feasible. U-238 makes up the bulk of the fuel but typically doesn't fission since thermal neutrons don't posses sufficient energy. If fast fission is occurring then there's A LOT more fuel left to burn and this disaster could carry on for significantly longer....
Here's direct evidence that there's still on going pockets of fission occurring... Surging radiation levels are also strong evidence of fission since you would expect radiation from decay to decline predictably.
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$200B US with no return....
Imagine how much solar, wind and storage could be built with ~$200B...
11.7 million homes could have 4.4Kw of panels installed at $17,000 per home.
That's about the population of Ohio, the 7th most populous state. California would be a better place to put all those panels
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mspohr
Well-Known Member
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