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Solar Is Cheapest Electricity in History, U.S. DOE Aims to Cut Costs 60% by 2030

(cleantechnica.com)
131 points mg | 16 comments | 26 Mar 21 20:07 UTC | HN request time: 1.925s | source | bottom
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zizee ◴[26 Mar 21 23:02 UTC] No.26598033[source]▶
I think the future will be robust national/international grids, with a mixture of storage options (batteries/pumped hydro) to smooth out the intermittent nature of wind and solar.

Cynics always talk about the amount of energy storage required for solar as if you need to store 24 hours of energy for solar/wind to be viable.

I'd like to see numbers on having 1 hour of storage for peak demand, a robust national grid, and appropriately provisioned and placed solar and wind, taking the duck curve into consideration.

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manfredo ◴[26 Mar 21 23:27 UTC] No.26598222[source]▶
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. That leaves geographically limited options like pumped hydroelectricity, and solutions not yet deployed at any significant scale like hydrogen fuel cells, synthetic methane, thermal batteries, flywheels, etc.

Realistically we should saturate daytime energy demand with solar, and if there aren't any scalable storage options by then switch gears and proceed with hydroelectric where it's viable and nuclear where it's not.

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nicoburns ◴[26 Mar 21 23:35 UTC] No.26598287[source]▶
> 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.

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manfredo ◴[26 Mar 21 23:43 UTC] No.26598345[source]▶
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).
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jeffbee ◴[26 Mar 21 23:48 UTC] No.26598377[source]▶
Nobody needs 1 full day of storage.
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ch4s3 ◴[26 Mar 21 23:55 UTC] No.26598416[source]▶
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.
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pfdietz ◴[27 Mar 21 00:29 UTC] No.26598608[source]▶
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.
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Manfredo_1 ◴[27 Mar 21 01:00 UTC] No.26598820[source]▶
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.

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1. pfdietz ◴[27 Mar 21 01:07 UTC] No.26598873[source]▶
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.
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2. Manfredo_1 ◴[27 Mar 21 01:10 UTC] No.26598899[source]▶
Right, and what company can I call right now to install 50GWh of hydrogen storage?

It's existing technology, but it's a novel application of that technology. We haven't used hydrogen electrolysis as a form of grid storage before. And we certainly haven't used it for grid storage at the Terawatt hour scale. And that the scale we'll need to make wind and solar viable. 1 TWh isn't even 30 minutes of global electricity consumption.

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3. pfdietz ◴[27 Mar 21 01:20 UTC] No.26598963[source]▶
50 GWh of hydrogen would fit in one salt cavern of the kind already made for natural gas. Any numbers of companies can solution mine those caverns for you; that technology is many decades old. I'd need more information about the rest of what you want, as that scales by power not by energy capacity.
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4. Manfredo_1 ◴[27 Mar 21 01:28 UTC] No.26599007{3}[source]▶
And are we currently using any of these caverns for electrolysis and grid storage? All you said is that we have a big cavern that we could fill with hydrogen. I'm asking if anybody is actually building hydrogen grid storage at any significant scale. Are there any facilities that take in excess energy from renewables, turn it into hydrogen, and then turn that hydrogen back into electricity?

We both know the answer: there aren't any.

Back in the 1950s people thought nuclear power would be cheaper than fossil fuels. They thought it'd be effectively free. The energy density of uranium is so much better, so clearly generating electricity with it would be much cheaper. But actually deploying a technology at scale reveals more and more challenges.

Your proposal for hydrogen storage is in the same phase that nuclear power was in during the 1950s. A solution that exists on paper, but one that hasn't actually encountered and overcome the challenges of implementing it at scale. Same with thermal batteries, synthetic methane, and so on. These are proposals that haven't passed the test of actual implementation at scale.

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5. Hypx ◴[27 Mar 21 01:43 UTC] No.26599089[source]▶
https://www.pv-magazine.com/2020/06/16/hydrogen-storage-in-s...

We could easily have Petawatt-hour scale hydrogen energy storage.

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6. Manfredo_1 ◴[27 Mar 21 01:51 UTC] No.26599131{3}[source]▶
No, you have salt caverns with a volume sufficient to accommodate a lot of hydrogen. Actually implementing such a solution involves massive scale electrolysis, and either massive scales of oxidation cells or gas turbines designed to burn hydrogen. Neither of these things have been done at anything remotely close to the scale required to make renewables feasible.

Back in the 1950s people thought that nuclear power would be effectively free. But actually building it at scale exposed challenges of implementation that weren't foreseen. The cost of a system on paper and the cost after overcoming the challenges of actually building it are two very different things. For hydrogen storage, you only have the former.

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7. Hypx ◴[27 Mar 21 01:58 UTC] No.26599162{4}[source]▶
Those gas turbines you're referring to can simply be modified natural gas gas turbines. The only limiting factor would be electrolysis, but that is already something people are planning to build a lot of.

Nuclear's problem are fundamentally political in nature. If we really cared about green energy, nuclear power could easily be built out at scale.

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8. Manfredo_1 ◴[27 Mar 21 02:06 UTC] No.26599213{5}[source]▶
No, hydrogen rapidly corrodes any metals that it comes into contact with. If they are interchangeable, expect drastically smaller service intervals.
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9. pfdietz ◴[27 Mar 21 02:24 UTC] No.26599307{6}[source]▶
> No, hydrogen rapidly corrodes any metals that it comes into contact with.

The industries that manipulate tens of millions of tons of hydrogen each year would be astounded to hear this statement of yours. What are those facilities made of, unobtainium?

10. pfdietz ◴[27 Mar 21 02:27 UTC] No.26599327{4}[source]▶
Dude. You are falling back to the "if it isn't already being done, it can't be done" argument. Please stop this foolishness.

Hydrogen is being stored in a few places. That the storage isn't larger isn't because of any technical obstacles, it's because there's no reason to store it now. In particular, when we can burn natural gas without CO2 charges, using the hydrogen for energy storage is pointless.

This doesn't mean hydrogen CAN'T be stored, it just means the market conditions for widespread adoption of an off-the-self technology aren't there yet.

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11. Hypx ◴[27 Mar 21 02:27 UTC] No.26599329{6}[source]▶
A claim which simply isn't true. Only certain alloys have a problem with hydrogen. We've been using hydrogen in industry for decades and most of this problem has been solved.
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12. Manfredo_1 ◴[27 Mar 21 02:38 UTC] No.26599399{7}[source]▶
We've been using hydrogen in the chemical industry. We haven't been using hydrogen to drive combustion turbines very much, and even then it's in a mixture of natural gas.

Unfortunately, those alloys that experience embrittlement includes the ones used in steam turbines: https://www.sciencedirect.com/science/article/abs/pii/S09215...

13. Manfredo_1 ◴[27 Mar 21 02:51 UTC] No.26599476{5}[source]▶
Storing hydrogen is only one piece of the puzzle. Yes, if you happen to live near an abandoned salt mine that's a convenient place to put a large quantity of hydrogen. That doesn't solve the problem of massive electrolysis facilities, and turbines that can burn hydrogen.

And it certainly doesn't answer the question of whether or not this represents a viable grid-storage solution, since we haven't built it at remotely close to the scale required.

It's not "if it isn't already being done, it can't be done"

It's "if it isn't already being done, it is extremely reckless to assume that it can be done cheaply at a massive scale".

Screw it, let's just use fusion. Nobody has actually built a fusion plant? Well, who cares if it hasn't already been done, that's a "foolish argument" in your own words. /s

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14. pfdietz ◴[27 Mar 21 03:03 UTC] No.26599541{6}[source]▶
These are not abandoned salt mines, they are deliberately created caverns in salt domes. The cost of creating them is included in the capital cost ($1/kWh capacity).

Hydrogen could also be stored in depleted gas fields and in deep saline aquifers. The storage capacity available is more than adequate.

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15. Manfredo_1 ◴[27 Mar 21 03:41 UTC] No.26599719{7}[source]▶
For the third time, storage is only one part of the puzzle. We also need a way to cheaply electrolyze water into hydrogen, compress it into the storage facility, and then use it to generate electricity. Nobody doubts that you can pump hydrogen into a big cave. What's dubious is transforming this into a usable energy-storage facility.

We haven't done this to provide 100 MWh of storage. How on earth can we be confident it'll be easy to provide 1 TWh of storage, or 10 TWh?

People mostly talk about lithium ion storage because that's what's actually available, besides geographically limited options like hydroelectricity. Until there's a company that's building dozens of gigawatt hours of hydrogen storage it's a moot point. It's a technology that exists the laboratory, not one that's commercially available.

16. Manfredo_1 ◴[27 Mar 21 05:26 UTC] No.26600148{6}[source]▶
Most companies are targeting hydrogen gas turbines to be produced in 2030 or 2040: https://www.siemens-energy.com/global/en/news/magazine/2019/...

They aren't "off the shelf" technology yet.