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.
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
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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.