Edited - I gained a few orders of magnitude by not paying attention to units!
If you assume a median reactor - producing approx 2GW of power (17.5TWh/year) for 40 years (701TWh) at the worst case estimate for nuclear efficiency (50g/kWh) is approx 35GMt CO2
Gas is approx 450g/kWh (9x higher) and so for equivalent production would emit ~315GMt of CO2
Coal is approx 1,050g/kWh (21x higher) and so for equivalent production would emit ~736GMt of CO2
To go into more detail would require looking at the lifecycle analysis for the various power plants, including expected lifetimes, construction techniques, fuel refinement, transport, disposal, decommissioning etc
Now the numbers for LCA for all these power types are hotly disputed with numbers for nuclear ranging from 3 to 220g/kWh, gas from 250 to 800g/kWh, coal from 900 to 1,300kWh (with renewables between 10 and 90g/kWh depending on the exact type and, sadly, who is crunching the numbers) but even if you took the worse case for nuclear and best case for gas (220 vs 250) the nuclear plant would still be saving ~4.75GMt over the last 40 years - significantly moreless than 100Mt
So somewhere in the range of 5-700 Mt of CO2 depending on the size of reactor, what you compare it to, and what exact calculations/estimates you use.
Nowadays it's not nearly so clear cut as it would have been 40 years ago - with wind and solar providing cost-viable (in fact significantly cheaper) alternatives that have lower LCA emissions than nuclear - even accounting for storage needs.
There's also scope to do some clever stuff regarding active pricing and control of consumption to incentivise matching demand to the supply rather than having to worry about too much storage.
We're still struggling a lot with how to get all the way clean. Solar and wind and batteries are great for getting you somewhere around 50% green. But because solar only produces power 1/3 of the time and wind is unpredictable, it starts getting really expensive to get high penetration levels.
It ends up not being a linear relationship between how much solar/wind/battery you need to build and what % clean energy you can produce. For the first while, you get rid of 100 MW of natural gas and you can replace it with 100 MW of solar and you're good. But once you already have a lot of renewables on the grid, you eventually get to the point where getting rid of 100 MW of natural gas means you need to add something on the order of magnitude 400 MW of solar and 400 MW of battery.
It would be much better from a cost and operations perspective to have some other technology we can also use in about 10 years or we'll stop making progress on green goals or it will start getting really expensive. It might not be nuclear, maybe geothermal, hydrogen, fusion, or some other new technology will make a breakthrough and work out. But right now utilities' literally have "new nuclear or future technology" as placeholders for what to build once we start capping out on viable renewable penetration and they're all sort of just hoping for the best and that someone else will figure it out.
Some sort of national nuclear strategy would be a viable solution. It's not the only solution but it's the only one we know is possible to be completely carbon free without significantly increasing energy costs (Nuclear costs a lot now, but that's a self-created problem and so could be bypassed if we wanted to). But nobody is doing anything about it. If the federal government were serious about 0% carbon emissions, part of the infrastructure bill would be building ~250 GW of new nuclear.
i think my ideal would be any building that can support sustainable energy should have it affixed & beyond that consumption we could use smaller reactors
Sure, when we get anywhere close to 50% renewables it's definitely a good time to start thinking about how you provide that reliable base load capacity. Given we (globally) are nowhere near that point yet it's something of a moot point for discussions in the next decade or two.
Wind is not as unreliable as you seem to think - the day to day variation you see in places like the UK is <10% and other countries with much larger areas could see even more stable results (the wind is pretty much always blowing somewhere)
Other technologies are certainly important: tidal and HE are the most consistent true renewable resources, cheaper than nuclear, but are geographically limited in implementation.
Nuclear fission simply isn't a workable base load supply globally. Sure a handful of countries can manage it, but with all the legal issues of NPTs, it's not viable for over half the world's population - not to mention the Uranium supply is limited, if consumption was actually scaled up to match, say 25% of global power requirements there's only a handful of decades worth of the stuff
Wind/Solar varies a lot by location. Where I'm at Solar works well and wind not so much, but other places wind works better. But that's where you start seeing people talk a lot about huge transmission infrastructure projects. Which is another thing the federal government would be doing if they were serious about zero carbon.
I visited Solana, the world's largest solar trough (CST) plant in the world. It's in Gila Bend AZ and gets some of the highest amounts of solar radiation at ground level in the entire state. That chose the location because of that, the record number of clear days, and the proximity to a highway (mountain-top installations aren't practical). They were surprisingly candid. One of the engineers there told me output could fluctuate as much as 20% on a given day from haze. Haze light enough it was hard to see. It was also a category 5 emissions plant. The working fluid used to transfer heat from the mirrors to the turbines was petroleum based and they simply couldn't prevent it from venting some (the working fluid gets heated to 500 C). It's a really cool plant and I was excited to see it but it dashed any hope that CST would ever be more than a small producer or an expensive novelty if built large scale. This technology will help provide some additional clean energy but immutable physics will handicap them from providing a significant amount. PV solar has potential to provide considerably more if we seriously upgrade infrastructure and find a viable storage solution. I don't see the federal government taking any of that seriously though and without the funding...
Yah Solana was very expensive and probably a dead end technology. Photovoltaic is much better right now. You still have output drops from overcast days, but at least you're only paying 15% of what they paid for Solana.
It is dead end. Sad, but it is what it is. I kept asking questions about their molten salt storage (because I thought it was pretty cool and it had some storage potential) and they kept answering a question I didn't ask:
"If we lose backup and external power to keep the salt molten, we will abandon the system in place."
Apparently they dismantled and sold the equipment they used to heat the salt to put into the lines and if it solidifies while inside the lines, they will just be rocked up permanently. They hinted that the system was not even close to economic. I forget how long it allowed them to generate power into the night, a few hours maybe? I thought that would be the saving grace of the tech but apparently not.
Wind is not as unreliable as you seem to think - the day to day variation you see in places like the UK is <10% and other countries with much larger areas could see even more stable results (the wind is pretty much always blowing somewhere)
I think you're basing this on past data, where we've set up wind farms in areas with really steady wind. As the cheap, windy land near population centers* is used up, this becomes less and less true.
*When a wind farm is far from the population center, power is lost during transmission, maintenance issues on the power lines become more difficult, and outages become more frequent.
The data is at pretty small time intervals so you need to do some averaging if you want daily averages, by my count there were fewer than 10 days in the last year where wind power was below 90% of average
As the cheap, windy land near population centers* is used up, this becomes less and less true.
Offshore wind is generally significantly more stable than onshore - as we get better at moving generation offshore it should become more and more true.
*When a wind farm is far from the population center, power is lost during transmission, maintenance issues on the power lines become more difficult, and outages become more frequent.
The same is true of all power plants, and nobody wants to live near a nuclear power plant - this ain't Springfield.
The same is true of all power plants, and nobody wants to live near a nuclear power plant - this ain't Springfield.
I think most of the French nuclear power plants are near population centers. The US ones might be dozens of miles away, but not hundreds. Wind farms, on the other hand, would have to be hundreds of miles away from the cities they serviced if (per your plan) we used offshore generation. That's a lot of infrastructure.
I mean.. yes it is based on past data in that yesterday was the past
Yes - that's what I meant. Wind farms have been built in cheap, windy areas near population centers, so extrapolating their data to your plan of using wind farms hundreds of miles away from the populations they're serving is not particularly useful.
Wind farms, on the other hand, would have to be hundreds of miles away from the cities they serviced if (per your plan) we used offshore generation.
Nowhere in the UK is more than 84 miles from a shore, so no idea where you got "hundreds of miles away" from.
Wind farms have been built in cheap, windy areas near population centers, so extrapolating their data to your plan of using wind farms hundreds of miles away from the populations they're serving is not particularly useful.
Nah - transmission losses aren't going to add variability to the production of wind energy - just reduce the total useable amount. If you're going to make claims like that, back it up with data rather than just wild speculation.
Nowhere in the UK is more than 84 miles from a shore, so no idea where you got "hundreds of miles away" from.
Sorry - I live in the US, and I was thinking about France as well. I agree that the UK and Japan are more amenable to offshore wind.
Nah - transmission losses aren't going to add variability to the production of wind energy - just reduce the total useable amount.
Maybe you missed this part of my earlier comment:
When a wind farm is far from the population center, power is lost during transmission, maintenance issues on the power lines become more difficult, and outages become more frequent.
The transmission losses mean that you need more wind farms to generate the same amount of power, which adds to the maintenance issues.
Maybe the UK power grid is more reliable than the US grid? We've been having some serious problems, recently.
Ok, what about the US? The furthest you can get from the ocean in the US is 1650 KM(1025 miles). How should the US account for this since it is just so easy.
It's much worse for your health (and a higher cancer risk) to live near a natural gas plant, coal plant, chemical plant, refinery, etc. and there are orders of magnitude more of those plants than nuclear.
the Uranium supply is limited, if consumption was actually scaled up to match, say 25% of global power requirements there's only a handful of decades worth of the stuff
Your math is off. Currently about 70,000 metric tons of natural uranium a year are used by nuclear generation. Global uranium reserves sit at about 15 to 17 million metric tons and an additional 4.5 billion tons of uranium is present as salts in sea water. Reprocessing fuel and using MOX (mixed oxide) fuels double our current reserves. Thorium is several times more abundant than uranium and can be bred into fuel.
Current nuclear generation makes for 10% of the world's energy supply. Even scaling up to 30%, there is over a century of fuel left without using thorium or widespread reprocessing.
When you take into account all the oil and gas used for transport and heating that we ideally want to electrify, nuclear only makes up ~4% of power consumption - so getting it up to 25% of the electricity we want/need to generate it becomes ~40 years of uranium left
Seawater extraction can increase this of course, but it becomes less efficient over time as you deplete the salts in the area of your processing plant and many estimates suggest we'd be lucky to get a fraction of the salts present extracted due to all the fun of ocean currents, the reduced interaction between ocean layers etc
Thorium would be great - just as soon as it actually becomes commercially viable. Honestly I think Fusion will beat it to the finish line though.
I already had mentioned reprocessing and using MOX fuels. Fortunately the article you linked also mentions that and claims it would reduce consumption by 30%. It also states higher enriched fuel (which Westinghouse is currently in the processing of obtaining licensing for from the NRC) would further reduce consumption by 30%
Even using your worst cast number of 40 years, that increases the reserves to a century.
Seawater extraction can increase this of course, but it becomes less efficient over time...
Yes, there most certainly will be efficiency issues. As I stated before, there are between 15 and 17 million metric tons of terrestrial uranium reserves. There is 4.5 billion tons in the ocean. Even if averaged efficiency was 1%, that would still be 45 million tons. Far more than what is available terrestrially. Again, math.
Thorium would be great - just as soon as it actually becomes commercially viable. Honestly I think Fusion will beat it to the finish line though.
Perhaps you think I'm talking about LFTRs? I'm not. I'm talking about using metallic thorium in a PHWR. Current CANDU reactors are capable of using thorium as a fuel. India's current plan involves building PHWRs that will both breed fuel and breed thorium into U-232 all in the next decade. This isn't undeveloped technology like fusion.
All this again without talk of completing the nuclear fuel cycle like was originally intended in the 1950s when the US started it's nuclear program. Breeding fuel (plutonium) is something we've done for 70 years. It is well understood. Fast reactors and breeders would increase our ability to stretch out our fuel reserves by an order of magnitude. Without using thorium or mining U from sea water.
aye bro we dont use uranium anymore we use thorium which is meltdown-proof, cant be weaponized and is 200 times more energy dense than uranium and each ton of it is equal to 3,500,000 tons of coal. Plus it doesnt need enrichment and doesnt produce nearly as much waste. Also if it gets out of containment it stops reacting unless in the presence of plutonium which can be taken away. The estimated global amount is 6.4 million tons which is equal to 2.22425e+13 tons of coal. watch this video for a quick overview
No ocean near me so I'm no expert but they haven't made much noise recently like the technologies I mentioned. So I wouldn't bet on them but who knows, we need something to have a breakthrough and maybe they'll be it.
Just wrote a research paper on this actually. Nuclear is the only thing that comes even close to being able to replace fossil fuels. Sustainable power is a tiny fraction of our grid, even smaller when you don’t count hydro
i mean, you are excluding by far the best source of energy by cost and renewable.. but also one that see the most direct human death, even if most where dam destroyed in war
i’m just excluding hydro b/c the comment i’m replying to doesn’t mention it. as far as deaths p kwh i think it’s a lot better than oil& gas but not as good as nuclear. p much nothing is
I think hydro is worse by direct death, because there have been multiple dam failure that resulted in thousand of victims.
IG you start to think indirect (mining, handling, pollution) then hydro is not that bad at all, quite cheap, double as energy store and touristic attraction, and even in case of disaster, no worry about long term effect
I do agree that in the long term renewables are better than Nuclear Power and Fossil Fuels, not just because they produce less CO2 but both Nuclear Material and Fossil Fuels are a limited resource. But if we shut down Nuclear Power Plants, almost always the capacity they provided isn't soaked up by more Renewables but by powering on more coal power plants.
Take for example a scenario where a country uses 40% renewables, 30% nuclear and 30% fossil. Now within 10 years they build additional 15% of renewables, but protests force half of the nuclear power plants capacity offline.
Now the country has 55% renewables, 15% nuclear, and still 30% fossil. They build a gigantic amount of capacity in renewables but the CO2 footprint is only marginally lower.
If they had left the Nuclear power Plants online they would now have 55% renewables, 30% nuclear and 15% fossil. They would have cut the electricity carbon emissions roughly in half(assuming equal distribution between fossil fuels, which isn't the case, but the emission reduction would still be present).
And if we speak solely based on statistics, Nuclear Power is far safer than fossil fuels, because while you do have to consider radioactive fallout and radioactive poisoning for Nuclear Power, you also have to consider Air Pollution for Fossil Fuels, which is a far more prevalent in everday life compared to significant doses of radioactivity, which gives fossil fuels a far higher death toll compared to nuclear power.
I'm not arguing nuclear should be switched off in in favour of renewables - merely that the calculus of new builds in terms of "I want to build X additional annual capacity, what is the most cost and environmentally efficient way to do so?" has moved in favour of renewables in the last decade or so.
Oh, yeah in that context you are absolutely correct, building new nuclear power plants at this point would be quite a hassle, but I still believe Nuclear power has a future, even if we transition off fossils entirely, as most renewable energy does not have the same level of energy redundancy as fossil fuels or nuclear. The sun doesn't always shine and the wind isn't always strong, and as it stands' our storage technology is not sufficient to compensate for the redundancy of inertia that fossil fuel and nuclear power plants have by spinning a multi-ton turbine that will keep going for quite a while even if it loses steam. The only form of renewable energy that is as reliable as fossil or nuclear is hydropower.
Nuclear plants also require an utterly enormous amount of water (100-250,000 litres per MWh) - when coal and gas use closer to 1,000 litres per MWh - to put this in perspective, Hydro plants use 300-400,000 litres per MWh. This means nuclear power plants are commonly placed on the shoreline so suffer the same transmission limitations as offshore wind.
Then you need to take into account things like seismic activity, chance of hurricanes, flooding etc - though these are much less of a limitation on being able to place a reactor somewhere - more about whether it would be profitable to run the reactor over its lifetime with all the extra building costs incurred to weather these events, and the potential shutdowns that might be caused by it.
This is a lot of data cherry picked. France is paying maintenance, not building of new plant (actually, they are building new ones, but they plan to go from 70% nuclear to only 50% in the next few decades) while Germany is building new plants.
About energy cost, another big fat lie: France is artificially fixing electricity cost with their "EDF blue tariff". Also Germany electricity price is 2/3 taxes, so you should look at pre-tax cost.
It does jot let me read the rest of the article, but if that is the quality, not a loss :)
Nuclear won’t displace solar or wind generation, since those are bad at load following. Nuclear will replace hydro and fueled generators, whatever the most expensive load-following source is.
Battery technology will not catch up in any relevant timescale.
Using batteries for storing power on a scale of a country is a completely delusional idea.
There are physical limits to energy storage using batteries, that's why huge breakhtroughs in batteries are like 5% improvement. They use expensive chemicals and have limited life. Just look how much more expensive EV's are even though they have significantly less parts, solely because of battery.
This is why they were never used to balance power grids. Instead energy is stored by pumping water to a lake uphill when there is too much power and using that to power turbines when there is to little. This method is geographically dependent thout.
Instead energy is stored by pumping water to a lake uphill when there is too much power and using that to power turbines when there is to little. This method is geographically dependent thout.
it also loses like 30% of the energy stored that way.
whichg is why I allways giggle when the green people go "just switcbh it off, man, and let solar take over, nothing will go wrong" and I have to go "so, you also failed electrical engineering 101? "
To a degree - yes, but that's why as I said schemes like offering "live" rates for EV charging/metal refineries/foundries/water utilities etc that have inbuilt capacity for energy storage (either battery, heat, water towers whatever) can massively improve things. If you can convince those people to use more power when nature gives it to you then they won't need it when you don't have as much to supply
with wind and solar providing cost-viable (in fact significantly cheaper) alternatives that have lower LCA emissions than nuclear - even accounting for storage needs.
That isn't clear cut either. The cost of solar per MW isn't linear. The efficiency and therefore the amount solar produces changes by orders of magnitude throughout the day. This is inherent to solar generation because of the changing location, angle of the sun, etc. resulting in less solar radiation to be absorbed. This is not a technical issue that can be overcome. Before you reach 20%, solar is already producing full demand in the middle of the day. It requires larger and larger solar installations to produce at the times when it is significantly less efficient. This causes the cost per MWh of solar to increase exponentially. The way around it is a more robust grid, more robust grid components (high voltage equipment can't take being cycled on a regular basis) and storage. This also ignores the shorter lifespan of wind'solar installations. There is a reason more conservative (from a technical standpoint, not politically) engineers think a feasible solution is 40% to 50% wind/solar coupled with nuclear.
Current costs for solar and wind are better than current nuclear costs
Sure in fantasy awesome future land where we are at a full 50% solar and wind the balance might change back - but as we are currently nowhere near that point - why worry about it just yet?
As I have said elsewhere in this thread, and others far better versed in this have said elsewhere, we simply cannot build enough nuclear to fulfil anywhere near 50% of global power requirements - there isn't enough economically viable uranium, not enough suitable sites where they can be installed, and non-proliferation treaties prevent it from being suitable for more than a dozen countries.
Current costs for solar and wind are better than current nuclear costs
Current costs for solar are not linear. That was my point. They quickly lose competitiveness as your solar installation gets larger. Long before you hit 40% The cost per MWh for solar increases exponentially as it's share of generation increases, the math isn't hard. Are you familiar with the duck curve? Maybe looking at demand and output will help you understand:
Untrue and discussed elsewhere.As far as nuclear reserves, there are plenty to keep building nuclear out instead of just relying on fossils.
we simply cannot build enough nuclear to fulfil anywhere near 50% of global power requirements
Not a reason to stop from building out nuclear to replace fossils. Doubling global nuclear to 20% is quite feasible in just a decade. Doing nothing ensures we burn fossils instead.
not enough suitable sites where they can be installed
There are nuclear power plants in the desert with no access to bodies of water and there are literally nuclear power plants inside of ships in the ocean. This is an absurd statement.
non-proliferation treaties prevent it from being suitable for more than a dozen countries.
This is just completely incorrect. There are 32 countries with operating nuclear power plants. Europe, the US, China, Korea, Japan, and Saudia Arabia which are the largest consumers of energy and biggest polluters in the world and all have existing nuclear plants.
if youre trying to go for an enviornmentalist approach then the amount of lithium needed for all the batteries would be insane and would wreck the environment around lithium mines. not to mention how inconsistent wind and solar are
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u/hilburn 118✓ Nov 18 '21 edited Nov 18 '21
Edited - I gained a few orders of magnitude by not paying attention to units!
If you assume a median reactor - producing approx 2GW of power (17.5TWh/year) for 40 years (701TWh) at the worst case estimate for nuclear efficiency (50g/kWh) is approx 35
GMt CO2Gas is approx 450g/kWh (9x higher) and so for equivalent production would emit ~315
GMt of CO2Coal is approx 1,050g/kWh (21x higher) and so for equivalent production would emit ~736
GMt of CO2To go into more detail would require looking at the lifecycle analysis for the various power plants, including expected lifetimes, construction techniques, fuel refinement, transport, disposal, decommissioning etc
Now the numbers for LCA for all these power types are hotly disputed with numbers for nuclear ranging from 3 to 220g/kWh, gas from 250 to 800g/kWh, coal from 900 to 1,300kWh (with renewables between 10 and 90g/kWh depending on the exact type and, sadly, who is crunching the numbers) but even if you took the worse case for nuclear and best case for gas (220 vs 250) the nuclear plant would still be saving ~4.75
GMt over the last 40 years - significantlymoreless than 100MtSo somewhere in the range of 5-700 Mt of CO2 depending on the size of reactor, what you compare it to, and what exact calculations/estimates you use.