Cloud cover doesn't stop all production, it just reduces it. Just build more solar and more storage and it will still be a fraction of the cost of nuclear. I could answer point by point but all of your "failures" are artificially constrained.
Cloud cover reduces solar production by 10-25%. If you need 10x overproduction, plus storage it's not cheaper than nuclear. That's not even counting factors like axial tilt (during winter the Earth is rotated away form the sun, reducing incoming light per M^2 of land), and the transmission infrastructure required to accommodate the decentralized nature of solar and wind [1] (which nuclear conveniently avoids since it's much more energy dense).
These aren't artificially constrained issues. These are real practical barriers. Why haven't countries the world over completely to renewables if it's cheaper? Because corporations want to screw up the environment because... they're moustache-twirling evil people or something? But the reality is that intermittent sources still have significant barriers to implementation that won't go away without massive, orders-of-magnitude improvements in storage performance. Renewables are good to deploy in an opportunistic fashion, supplementing dispatchable sources during periods of production and then turning the gas back on when they're not producing. But actually producing a primarily renewable grid becomes vastly more challenging due to the intermittency.
Fossil fuel companies are those mustache-twirling profit optimization villains, and there is demonstrated evidence that they have run a decades long campaign against any form of energy that is not fossil fuel...
10-25% short fall doesn't require 10x over capacity, it requires a mix of overcapacity + storage + energy conservation measures.
The energy storage at relevant scale is nowhere near feasible as other comment chains explain. "Energy conservation" is just an admission that these sources can't generate enough energy.
Other comment chains have explained the storage scale you claim is needed, isn't a great estimate.
Energy conservation is probably a better payback than either nuclear or renewables and better resilience for people infrastructure. For example, better insulation reduces energy costs in both cold winters and heat waves, and reduces the impact if there are grid/source failures by any technology. It also doesn't have a big crossover on the logistics tail of either nuclear or renewables, and so is a great thing to do in parallel to address climate change in general.
"Conservation is an admission of failure" is a purely ridiculous position.
The estimate of 12 hours of storage was one of the more optimistic ones. It's not just day/night cycles there's also weather that results in long term fluctuations in output. Some of the estimates call for weeks of storage.
Energy conservation is likely not going to be feasible as more and more transportation gets electrified, as gas heating is replaced with electric, and industrial processes like smelting are decarbonized. Conservation is indeed an admission of failure, because success involves accommodating the growing demand for electricity in the future. Remember, electricity production is only about a third of total energy consumption: https://www.eia.gov/energyexplained/us-energy-facts/
Estimates for weeks of storage are made by people who don’t understand the fundamental cost optimization going on.
More production costs X which reduces the need for batteries by Y, as long as X > Y you build more production even if most of it’s output is unnecessary. Also 16% of global electricity comes from hydroelectric generation, we really don’t need that many batteries.
Actual optimized energy storage is on the order of 2 to 6 hours total globally ~30 years from now depending on how much prices drop. With larger numbers representing lower battery prices. In the shorter term it’s a tiny fraction of that.
2-6 hours is nowhere near enough to offset daily fluctuations, let alone seasonal fluctuations. Overproduction only gets you so far, unless this proposal also involves transoceanic HVDC cables. Hydropower is not exactly the same thing as storage: you can stop releasing water and build up the reservoir, but you cannot pump water up river. Even just 6 hours of storage -which would not be sufficient even with several factors of overproduction - is 15,000 GWh of storage to satisfy present global electricity use.
Overproduction means you don’t ever see daily fluctuations you have a surplus every single day of the year. Unless storage gets insanely cheap that’s by far the cheapest safe option.
Hydropower dams are already storage. When you don’t release the water it’s saved until you do.
If you have enough rain from 3 months ago to release 10 MW 24/7 over a week then you also have enough water to release 15 MW for 12 hours and 5 MW for the other 12 every day etc. You can’t save 100% of the water or the river downstream runs dry but the minimum is generally well below the average flow rate.
This isn’t unusual, most dams ramp production up and down to maximize the value of the stored water.
> Overproduction means you don’t ever see daily fluctuations you have a surplus every single day of the year.
No, this is not even remotely true. No amount of solar overproduction will let you produce energy at night. 12 hours a day (on average, depend on the season) you will not have any production regardless of overproduction. You'll have a lot of excess energy during the day, but still no energy when the sun has set. Infinity times zero is still zero. Not unless you create transoceanic HVDC cables that connect Eurasia to the Americas, literally piping electricity from one side of the world to the other. Wind also has windless days, with more extreme seasonal fluctuations. Overproduction is not a silver bullet that eliminates the need for storage. Just because you have net surplus over the course of a 24-hour period does not mean demand was satisfied at all times. This is why intermittent sources are so challenging.
> Hydropower dams are already storage. When you don’t release the water it’s saved until you do.
But you can only save energy at the rate that rainfall refills the dam. If you have a dam that refills at a rate of 10MW, you can only effectively store 10MW of excess energy. If you have 20MW of excess production, you can still only store 10MW and the other 10 MW is wasted. Dams are not batteries, they can store a lot of energy but they can only be refilled at the rate dictated by rainfall.
You also can't completely shut off a dam or the river will run dry with serious ecological consequences, and impairing downstream water supply.
> Excess per day doesn’t mean you get solar power every single second just per day, that’s what batteries are for.
...which would require an enormous and infeasibly large amount of batteries. You're right: overproduction doesn't mean you get power for every second per day. But a grid does need sufficient energy at every single second per day or you have blackouts. This is why overproduction of intermittent sources is not as useful as it sounds.
Nothing in your link about dams contradicts what I wrote: their rate of recharge is limited. You can shut off much of the turbines and let the reservoir build up, but they cannot be recharged faster than the rate at which rainfall refills the reservoir. Judging by a 2 GW capacity and 23% capacity factor, one would infer that it's refilled at a rate of ~500 MW (in reality, less than that since Lake Meade is shrinking). Completely shutting off the turbines would only refill at a rate of 500 MW. If you have 2 GW of overproduction, you can't refill Lake Meade with 2 GW of potential energy. You can shut down its turbines and let the reservoir refill at a rate of 500 MW, but the other 1,500 MW can't be used to recharge Lake Meade.
A dam is sort of like a battery but its rate of recharge is much more limited than it's rate of discharge, which is a big disadvantage when trying to capture the overproduction from intermittent sources.
> ...which would require an enormous and infeasibly large amount of batteries
False, but you can’t substantiate your argument by simply saying the words you need to back it up with something such as actual calculations etc.
> Their rate of recharge is limited
That’s completely irrelevant here. Rainfall is so concentrated in short periods that they often have months of water in reserve and can decide when exactly to release it over that kind of timeframe. 95% of the time there is less water flowing out of a dam than flowing into it. That’s why we build dams.
The rate of recharge is absolutely relevant, because you can't actually capture excess production from intermittent sources. If you're relying on a dam to fulfill periods of non-production, you need a way to put the excess energy during periods of overproduction back into the dam. But a dam can only shut down its turbines, it can't be recharged faster than the rate that rainfall refills it. If you need 40% of your electricity coming from dams during periods of non-production, then you need rainfall sufficient to produce that much energy. It's not like a battery where you can take excess production and store it back in the dam. That's how pumped hydro electric storage works: you run turbines backwards and refill the dam with excess energy. But pumped hydro requires a very specific set of geographic features, and is not easy to scale up.
> If you're relying on a dam to fulfill periods of non-production, you need a way to put the excess energy during periods of overproduction back into the dam. If you're relying on a dam to fulfill periods of non-production, you need a way to put the excess energy during periods of overproduction back into the dam.
I understand your point but it’s based on faulty assumptions.
Simply not using existing water means it’s still there. If you have 10,000$ in your bank account and you don’t buy something you still have the 10,000$. Dams are the same way if you have 20,000 MWh worth of water and can average 20 MWh for the next 1,000 hours then generating 10 MW for the 500 hours of those hours and 30 MW for the other 500 hours hits zero at exactly the same time.
Recharge is important long term but irrelevant in the short term. You might expect to receive water from the spring thaw, but that’s a long way away. Large dams like the hover are built to contain multiple years worth of average flow for a river. It took more than a full year just to collect enough water for them to start generating hydropower.
As to your analysis,
> 500 GWh globally
That’s an outdated estimate for last year even just EV’s broke 500 GWh. “Automotive lithium-ion (Li-ion) battery demand increased by about 65% to 550 GWh in 2022, from about 330 GWh in 2021” https://www.iea.org/reports/global-ev-outlook-2023/trends-in...
Your number was an estimate for 2022 total production made during 2022, and they got it wrong which isn’t that surprising as EV sales ended up 55% from 2021 and average battery sizes also increased. 2023 numbers are hard to estimate for similar reasons.
> Production of batteries may grow in the future
Again, the rates have been increasing by double digits per year for a long time, that’s wildly faster than the increase in electricity demand. We don’t need to talk in hypothetical terms here just current factories already wildly invalidate your calculation let alone any kind of longer term estimates when grid storage may start to pick up.
> 12 hours
As I mentioned that’s a monumental overestimate, but not particularly relevant compared to the first two issues. We can quibble about specifics here but compared to even a 50% EV world grid storage simply isn’t a major factor.
Rate of recharge is the limiting factor of the total amount of energy you can release from a dam without reducing the total amount of water in the reservoir over time. Hoover dam may be able to produce 2GW of power, but if it averages more than 500 MW it will drop in water level over time (actually less than that, since it's already reaching record low fill levels). True, rainfall is not constant throughout the year. But it doesn't really matter in the big picture: the total amount of energy you can produce with the dam without lowering fill levels is fixed, and it isn't changed by overproduction.
Overproduction doesn't help you here: if you have 3 GW of solar energy and 2 GW of electricity demand, you can't use the remaining 1 GW to refill Hoover Dam. If you produce enough solar to meet demand, you can shut off hoover dam's turbines. But if you overproduce - if you produce more energy than the grid needs - it's wasted, you can't use excess energy to refill the dam beyond just shutting off the turbines.
> That’s an outdated estimate for last year even just EV’s broke 500 GWh. "Automotive lithium-ion (Li-ion) battery demand increased by about 65% to 550 GWh in 2022"
Demand, not production. Just under 500 GWh of batteries was produced, a good chunk of demand went unfulfilled. If anything, all your source shows is that grid storage is even more infeasible because we can't even satisfy EV's storage needs.
> As I mentioned that’s a monumental overestimate
No, if anything it's an optimistic underestimate. 12 hours is just enough for diurnal storage. But you also need storage to offset seasonal fluctuations.
