How about all the uranium leftovers from enrichment and the cold war?
Spain to dismantle over 30% of wind turbines in next 5 years
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Are these external energy ratios or net energy ratios?
It should be noted that EROI is incredibly sensitive to the methods of calculation and can be easily tweaked to appear more or less favorable to any given energy source by choosing where to draw the lines on energy input.
Here’s a case in point: https://www.researchgate.net/public...s_of_Net_Energy_Return_for_Wind_Power_Systems
While I’m not saying I agree with this paper, I do think it’s important to understand the methods behind any given EROI comparison in detail rather than take it at face value.
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OVERKILL
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Requires special designs like the CANDU to utilize depleted uranium.
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Debating the blanket worthiness of any energy source is kinda pointless, in a certain sense. The markets determine it. Sure, there are variable incentives, some (most? lol) of which are dubious, but it’ll shake out in a global scale in the long term.
Every source has substantial pros and cons which become more or less impactful depending on geography. There’s no single prescription that works best everywhere. No free lunch in physics. Developing technology to achieve a breadth of competing options is a good thing, overall.
Every potentially economically viable energy tech has applications, benefits, and future runway potential that needs to be considered.
Every source has substantial pros and cons which become more or less impactful depending on geography. There’s no single prescription that works best everywhere. No free lunch in physics. Developing technology to achieve a breadth of competing options is a good thing, overall.
Every potentially economically viable energy tech has applications, benefits, and future runway potential that needs to be considered.
OVERKILL
$100 Site Donor 2021
Yes, which is at least part of the reason why you'll find more attention given the lifecycle emissions, which are impacted similarly but more thoroughly researched. For example, going from old school enrichment, which nobody uses anymore, to gas diffusion, using centrifuges, massively reduces the lifecycle energy consumption of a nuclear source, which reduces lifecycle emissions and improves EROEI but many of the papers use old data sources that don't factor this in. They also tend to use ore grade levels that are much lower than what are currently being used. When you power that process with a non-emitting source (see: France) then you again reduce lifecycle emissions. The lifespan of the equipment is also critical. Many old papers used 30-40 years for nuclear lifespan, while most facilities are now licensed for 60 years, some 80 years.
This is partly why the IPCC figures for nuclear lifecycle, which include many old studies, differ from those of the UNECE, who use more modern data sets.
Summarized:
UNECE:
An interesting subject brought up recently by Seaver Wang, in one of his threads on solar module construction in China, was the problem of displacement. The argument is that lifecycle emissions are directly linked to displacement of other sources, and hinges on what those sources are. The emissions invested in the technology (embedded emissions) are recouped as emitting sources are displaced by the non-emitting one, so the embedded emissions need to be displaced before you have a net positive emissions reduction.
So, for example, if you used 1,000 tons of coal to produce a group of PV panels and those PV panels went into a grid where coal was the primary source, they would be directly displacing the emissions of coal, so the lifecycle emissions are low, and the payback period short, due to the displacement of the highest emitting source. PV on a grid that is primarily gas then has higher lifecycle emissions and a longer period to hit net positive, because gas has lower emissions to be displaced, but overall, still an easy net positive for the grid. However, If PV starts displacing say hydro, which has lower lifecycle emissions, it arguably will never reach net positive, because you are displacing a source with lower lifecycle emissions from the get-go.
It's an interesting way to look at it, because it forces you to look at where the next kWh would be coming from that is to be displaced and if that's actually worthwhile.
Yeah and the fuel is nearly free just have to form it into fuel rod assembles for candu or blend it with recycled fuel that contains elevated fissile isotopes.
What about that laser enrichment tech we stole from Australia?
It's supposed to be the fastest most efficient way yet to enrich uranium.
OVERKILL
$100 Site Donor 2021
I think we need to see that actually in operation to get a handle on its energy use. Up here in the GWN, the CANDU's don't use enriched fuel (natural uranium instead), combined with the highest ore grades, the energy embedded in fuel fab is insanely low.
Breeder reactor and reprocessing was not done everywhere because the cost does not justify the profit. If we need to we CAN reprocess spent fuel and certify / make MOX fuel for many existing reactor. The bigger problem is actually in the regulation, politics (NIMBY), concern of proliferation in hostile nations that currently still have no nuclear weapon, and competition with oil and gas industry we also own. This is why you see reprocessing done in France and maybe China, but not in Russia or US.
If we end up one day in long term energy crisis we certainly will see breeder reactors popping up AND reprocessing.
Any nation could have nuclear weapons. But they're all trying to copy the Russian and American nuclear weapons program models that makes a lot of nuclear weapons really quickly, problems with that are the USA and USSR models have really high start up costs, the weapons grade fuel is kind of hard to make, requires kinda precise implosion of the pit and a trigger to really make sure it goes off.
There's another way to breed fuel but it takes a long time but it's really really cheap and really low tech. Assuming you could make enough of it there's no need for precise implosion or a trigger device.
I am sure you can always find ways to breed fuel if you do enough work to get it, whether it is putting thorium or depleted uranium into a reactor to absorb neutron. The problem is typically having to build a reactor that is tested enough to convince population it is safe. Most researches takes time and money and we already have something that people don't think much about, so the cheapest way is to keep using what we have and just make it bigger, adding redundancy, safety, etc.
Sure if Afghan want to breed fuel low tech they probably could, and wouldn't turn weapon grade, but it would still be a political disaster for US, so I'm sure we also want to prevent that.
Would really need a huge energy crisis (even a local one like if China got blockade, and have to do something quick and will take the chance) to do something drastic. This is why most technologies were initially developed for military at war time instead of civilian at peace time.
I suppose I should point out that the largest nuclear power plant in the United States, which also happens to have the highest net generation of all power plants in the US, Palo Verde Nuclear Generating Station. It is located in the middle of a desert. There are no rivers, and obviously no ocean or seas, for cooling water. 100% of the cooling is via cooling towers, using reclaimed waste water from the Phoenix metro area. It's 3 Combustion Engineering reactors generate 11.97GW of thermal power, and it has a nameplate capacity of 3.937GWe. The 9 cooling towers each dissipate ~893MW of heat, for a combined thermal dissipation of 8.033GW. BTW, that's 33% efficiency, which ain't bad for a nuclear power plant.
Something like that would be great in a cold climate.
Circulate the hot water through pipes and radiators in buildings, as a heat source.
OVERKILL
$100 Site Donor 2021
Yep, that district heating arrangement is exactly how the AP1000's in China are setup.
And why are we not capturing the “waste heat” in cooler months to harness that energy for residential or commercial heating?
, a false narrative that is sold to whatever sucker believes it…These guys are save the fish
happy and don’t buy it:
Frequent Questions—Offshore Wind and Whales
Frequently asked questions about interactions between offshore wind energy projects and whales.
Yeah, the anti-renewable bent of this forum is tiresome. People have their positions pretty much staked out and just pick at their non-preferred solutions to (insert energy use here).
Replacing existing windmill blades with more efficient windmill blades? Whoda thunk it.....
OVERKILL
$100 Site Donor 2021
They don't replace the blades though, because usually by the 20 year mark the whole head is pretty much worn-out. Repowering you would think would make sense, reusing the base and tower, but new designs are larger, with larger blades, requiring taller towers and bigger bases, and more space between units, so it's a tear-down and replace situation instead.
Now, there are offshore wind turbines where the blades have been replaced, but that's at like the 10-15 year mark, not the 20 year mark.
I know you make reasonable posts Mr. Overkill, it's just some folks that make overarching statements about rapidly evolving technology.
BTW your EROEI chart is backwards from anything else I've seen, where the Y axis is cost based. Lowest EROEI cost was on the far left in the late 1800s/early 1900s where the oil was basically shooting out of the ground.
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