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.
1. https://www.vox.com/videos/22685707/climate-change-clean-ene...
10-25% short fall doesn't require 10x over capacity, it requires a mix of overcapacity + storage + energy conservation measures.
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.
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/
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. 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.
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.
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.
> But you can only sacs energy at the rate rainfall refills the dam. > can’t completely shut off
You’re completely misunderstanding how dams are used look here: https://en.wikipedia.org/wiki/Hoover_Dam
Installed capacity 2,078.8 MW, Capacity factor 23%
Minimum flow rate isn’t 0, but is plenty low enough to have a great deal of flexibility.
...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.
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're relying on 2GW of power from hoover dam at night, you can't overproduce 2 GW of solar power during the day and put it back into the reservoir. At best, you can shut down the turbines at let rainfall refill it 500 MW, but you'll be chronically losing energy. Rate of recharge is critical if you're trying to store energy during periods of overproduction, which is exactly what your proposal calls for.
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.
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.
Again, peak electricity demand does not happen at noon. It happens at around 9pm, when the sun either has set or is about to set. Unfortunately, solar's production does not match demand patterns.
> Instead of proposing cross-continent distribution lines, just build more small regional renewable sources...
Again, all the renewable sources in the same region are subject to the same weather patterns and and day/night cycles. Sure multiple solar farms gives you redundancy against some sort of mechanical failure that causes one specific solar farm to go down. But the most common failure mode in intermittent sources is cloud cover or lower-than-expected wind speeds. A backup solar plant a mile away isn't going to give you redundancy against weather patterns. This is why a lot of plans for renewable grids are contingent on thousands of miles of HVDC lines to move energy across continents.
> Capacity factor does not address reliability or emergency planning...
Capacity factor describes the uptime of a power plant. Nuclear power has the highest uptime. The point is it's less likely to go down than all alternatives.