To make solar power viable, we need a solution for overnight energy storage.
Batteries are complicated.
Do you know what isn't? Water go up. 
Within ecological limits I guess? That is the only real cause for concern with whatever gets you nerds hot - renewables or nuclear. Storage is necessary for both intermittant and the category of 24x7 until it's not and suddenly you have to have 1.6GW types of power generation. And from the wikipedia articles I have skimmed pump hydro is the gold standard.
Pumped hydro is a fantastic technology. It is unfortumate that we live under capitalism where development operates according to profit and not overall human benefit, so hydro dams are planned regardless of impact on indigenous communities or environmental and population harms. Countries rum by socialists will do a better job with this, particularly China, where pumped hydro dams are even sometimes combined with aquatic solar farms. While imperfect, these developments are far better than anything you're in fully capitalist countries.
There are actually many examples! A recent one with good English copy is here: https://www.scmp.com/news/china/science/article/3225408/china-worlds-largest-hybrid-solar-hydro-plant-produces-electricity-tibetan-plateau
I'm more into the big wheels in concrete wells, but different solutions are required for different areas and it's all better than fucking PtX bullshit hydrogen.
Putting the big wheels in wells is a waste. We should build them up into the sky so everyone can look at the big wheels and feel happy.
I've also seen a version of this that uses an electric locomotive that moves a big weight up and down a slope.
Personally I think we should put big weights on pulleys in every high rise, like a grandfather clock.
How To Make Buildings Into Batteries
https://piped.video/watch?v=oCv3ygvEjFo
Personally I think we should put big weights on pulleys in every high rise, like a grandfather clock.
How big? Seems like you would need quite a bit of weight to store any useful amount. Using this calculator: https://www.calculatorsoup.com/calculators/physics/gravitational-potential.php and assuming my values are right, if you had something the size of a bus (16,000 kg) pulled up through something as tall as the Empire State Building (380 m roof height), you'd get about 16.56 kWh, which isn't all that much. I think a typical EV battery size is about 40 kWh in comparison. With hydro storage on the other hand, you can store a shit ton of water in a reservoir without any major constraints besides the overall size, which is massive.
That's a good idea. They already have shafts that have the capacity for big weights as well
There's also a version of this where you divert water at a regular hydro plant into a storage canal. It still uses pumps, but it doesn't need a separate turbine and a mountain.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
What makes sand so great? Water has five times the specific heat capacity.
Edit: OH I see, the sand goes through a phase change. That involves a lot of energy, yeah.
you can use saltwater for it though, doesn't need to be fresh water or treated in any way, just a physical medium to make turbine go brrr
Machinery and saltwater generally don't mix very well. And you'd still need to make a saltwater lake somewhere uphill.
yeah but in this case it's just a pipe and a turbine it's gotta make move
And you'd still need to make a saltwater lake somewhere uphill.
water tanks tho
Saltwater damages turbine blades very fast. Using saltwater would require some very different engineering for the turbine blades, which might not be worth the benefit of being able to use saltwater.
Turbines are precision machines. And if we're talking utility scale installations here, we want an upper reservoir measured in thousands of cubic meters, not liters.
For places without water, what's wrong with importing a bunch once? Evaporation suppressors exist to help with hotter climates.
You're probably right about the hills. Building a water tower that can hold an entire lake seems inefficient.
from somewhere import lake
lake.flow()
It's just that simple!
Honestly, one of the better ways ecologically to store energy instead of ripping apart the earth to get rare elements for batteries. But I do also like flywheels, lets just store energy in flywheels.
I've also seen a version of this that uses an electric locomotive that moves a big weight up and down a slope.
Personally I think we should put big weights on pulleys in every high rise, like a grandfather clock.
It's good. Like hydro power, the viability is going to be highly site-specific. But it's a bunch of well known parts, so if some geological engineers say a particular pumped hydro installation makes sense, I'm going to trust them.
I think battery and synthetic fuel technologies will continue to improve, and the range of places where pumped hydro is the better choice will shrink over time. But in the best sites, I expect it's probably going to stay the most efficient choice for a very long time, the same way the biggest hydro power plants dwarf the biggest nuclear plants.
Okay okay, this off topic but
We should like build more molten salt nuclear reactors or something, they're so cool
Or maybe some of those
bed reactorsSo many options for nuclear reactors these days
We will definitely need a variety of different power sources
China trying I guess? They are more invested in fast reactors and light water reactors and see them as purely experimental considering what happened in Germany with the THTR.
Can work if the environment is good for it, has the same ecological and geological problems. Artificial water towers would be quite a big project maybe?
