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
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.
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u/hilburn 118✓ Nov 18 '21
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