[Manuel_D]

> It's called off river or blue field pumped hydro

This isn't built in sufficient quantities, and hasn't seen significant growth in decades.

> and sodium batteries.

This hasn't even been commercialized at all yet, let alone at grid scale.

[Schroedingersat]

Well, which technology passes this high-vault bar? Surely not one that is flat and possibly shrinking and is operating at a scale that is similar to that of grid storage and also needs storage to meet variable demand?

[Manuel_D]

None: there is no feasible method of grid storage at the moment. Hence why dispatch-able sources of clean energy are necessary

[Schroedingersat]

So which dispatchable sources can match the scale of energy generation at which renewables saturate the grid then?

[Manuel_D]

I explained this in the first comment to which you responded [1]. Hydroelectricity is by far the most effective source of energy generation, although it has the distinct disadvantage of being geographically limited. Nuclear power is the most effective dispatchable source after that. Every country that has decarbonized their electricity grid has done so primary through a combination of hydroelectricity and nuclear power. No developed country has deployed a majority wind and solar grid, ever.

1. https://news.ycombinator.com/item?id=33636418

[Schroedingersat]

A nuclear reactor requires about 0.5-1 tonnes of fissile material per GW per year and 3 to 6 years up front. Where is it supposed to come from?

[Manuel_D]

Mined, from the earth. Unlike lithium [1] uranium prices are not experiencing cost overruns. And unlike grid storage, nuclear power already makes up 10% of the world's electricity generation. We only need an 8x increase (another 10% of electricity already comes from hydro) instead of a 1000x increase like we do with grid storage. The thing about nuclear energy is that there's so much energy contained in uranium that more exotic forms of extraction like seawater absorption [2] is feasible. Unfortunately the same cannot be said of lithium. Some estimates predict that lithium reserves may be exhausted by EV production alone [3]. The volume of lithium required for batteries is considerably greater than the amount of uranium needed for fission, which makes seawater extraction non-viable.

1. https://tradingeconomics.com/commodity/lithium

2. https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...

3. https://www.lowyinstitute.org/the-interpreter/race-lithium#:....