[nicoburns]

> Even achieving just one hour of storage globally amounts to 2.5 TWh of storage. By comparison the entire world produces ~300 GWh worth of lithium ion battery annually

... so if we could increase battery production by just 10x, then we could create an hours worth of storage every year. That seems... very doable.

[manfredo]

And then we'd have to continue that production for two and a half decades to get to 1 day of storage. And we'd also have to drastically increase our battery recycling capacity to match (remember most lithium ion batteries last 1000-2000 cycles).

[jeffbee]

Nobody needs 1 full day of storage.

[ch4s3]

One could imagine a series of cloudy windless days in the northern latitudes during the winter. Perhaps a large enough gird solves that problem? I have no clue.

[pfdietz]

One would not use batteries for the "rare, but prolonged" storage use case. You'd want something with lower capital cost, even if it were much less efficient. For example: hydrogen burned in turbines.

[Manfredo_1]

Hydrogen storage remains in the prototyping phase. We have no significant amount of hydrogen grid storage. Like thermal batteries or synthetic methane, hydrogen represents a potential storage solution but not one that we know will scale and be effectively deployed at the scope required.

If we actually deploy 50 GWh of hydrogen storage, and demonstrate that it can cheaply and reliability be built at scale then your point would be valid. But until then, hydrogen represents a theoretical solution not an actual solution.

[philipkglass]

Hydrogen is stored underground in Texas salt formations at Clemens Dome, Moss Bluff, and Spindletop. The largest of them, Spindletop, was completed in 2017:

https://www.airliquide.com/sites/airliquide.com/files/2017/0...

This presentation says that the Spindletop hydrogen capacity is equivalent to ~120 GWh.

https://ukccsrc.ac.uk/wp-content/uploads/2020/05/John-Willia...

[pfdietz]

All the components of hydrogen, with the possible exception of low cost electrolyzers, don't need to be prototyped. It's existing technology. It's not like (say) molten salt reactors, in which fundamental development remains to be done.

[rhodozelia]

Who pays for the shadow generation system that we keep perfectly maintained and ready to generate 100% of system demand on the 5 days stretch of cloudy windless days? This cost has to be added to the cost of building a 100% solar/wind system.

Nobody is arguing the solar and wind power isn’t cheap, but the cost of power on those cloudy windless weeks is going to be real high to make having all that standby generation around. It’s the cost to achieve the same reliability and 99% carbon free that is expensive.

Money is imaginary and global warming isn’t so let’s just print some bonds or move some numbers around in some database and build it all! - an electrical power engineer

[pfdietz]

The cost will be there, but overall it looks like it will be cheaper than nuclear.

[acdha]

That’s a problem if you’re an island isolated from everyone else, and you don’t have geothermal, hydroelectric, or nuclear options. The better question is how much capacity you’d need on a national grid to be able to handle large regional sags in production without endangering people.

As we recently saw with Texas’ catastrophic fossil fuel production failures the big problem is not the source but poor management and not being able to get help from the neighbors.

[lutorm]

But the key is that if you're averaging globally, the solar power probably doesn't change much. You'll need a way to transport the energy instead, obviously.

[nicoburns]

If we had smart metering, then we could simply restrict consumption in these (presumably rare) circumstances.

[Manfredo_1]

We'd actually need 3 weeks of storage to migrate to a fully renewable grid: https://pv-magazine-usa.com/2018/03/01/12-hours-energy-stora...

[Qwertious]

From your own source:

"The solar heavy network wouldn’t need energy storage with an HVDC network."

So no, we wouldn't need that. HVDC would be far cheaper.

[Manfredo_1]

A solar heavy network would still need 12 hours of storage to accommodate nighttime energy use. More actually, because of greater seasonal fluctuations further from the equator.

All of the Americas experience night time simultaneously for at least 8 hours a day. Even if we ran HVDC lines to the Sahara, there's still a period of time where most sunlight is shining on the pacific ocean.

[Qwertious]

Yes, 100% solar makes no sense. Thankfully, we have other sources such as wind.

Also, if you can run HVDC to the Sahara you could run it to hydro plants, so I don't think that's a good hypothetical.

But mostly, talking about pure solar just makes no sense.

[thiht]

That sounds extremely expensive and not very green.