This was the most comprehensive study I have read:

[300 page pdf - warning]

https://www.google.com/url?sa=t&source=web&rct=j&url=https:/...

I have always been skeptical that grid storage was the hidden cost of solar, and that multiple weeks of total grid output storage were needed, but this makes convincing arguments that only a few hours of storage is needed, even in difficult areas.

A few hours in nowhere near enough.

In Finland solar produces no power three months of the year. The months before and after that are marginal. To add joy, there are windstill periods of days, sometimes more than a week, in winter.

To add insult to injury, there isn't enough transmission capability to import all the renewable energy we would need to solely rely on renewables. There isn't enough hydro either so rely on that to take up the slack.

So, grid storage really is the hidden cost of both solar and wind, and multiple weeks of total grid output storage is needed for energy security if relying on renewables.

To reinterate, I really want to learn more about real long term storage. Anybody know where I can find solid info on that?

did you read parts of the link at all?

Yes, but it's 280 pages. Which parts in particular address long term storage?

Searching for "storage" gives very few hits. This was perhaps the most pertinent hit:

"IT IS GENERALLY NOT ECONOMICALLY FEASIBLE TO store electricity in bulk. The widespread deployment of new storage technologies and/ or high penetrations of electric vehicles may someday change this, but these developments are unlikely before 2030."

along with this:

"Compressed air energy storage (CAES) is the only other storage technology [other than pumped hydro] that has achieved long-term utility-scale operation. ... Only two utility-scale CAES facilities have been constructed worldwide: a 290 MW facility with two hours of storage in Huntorf, Germany, that entered commercial operations in 1978 and a 110 MW facility with 26 hours of storage in McIntosh, Alabama, that entered commercial operations in 1991."

Not very much to go on, now is there.

This is my fault. I posted the wrong study:

https://energy.mit.edu/research/future-of-energy-storage/

Crap, posted the wrong link earlier. What I meant to post was a different study from the same series.

https://energy.mit.edu/research/future-of-energy-storage/

This model thinks that 5 hours gets us to 97%:

https://reneweconomy.com.au/a-near-100-per-cent-renewables-g...

5 hours is pretty doable with batteries and pumped storage. It's a lot and very expensive but not an impossible amount and there aren't any cheaper/quicker alternatives that I'm aware of.

I think Australia will be almost half way to 5 hours already once Snowy 2 is finished. That's just one pumped storage plant & studies show that the geography to build more is plentiful.

That last 3% can probably be eventually provided with via hydrogen, which, unlike the other two, is inefficient to roundtrip (~45%) but it lets you store large amounts of power for long durations easily.

Glad to hear someone else beating the hydrogen (or some e-fuel) drum for that last few percent.

I do not understand why there is not more focus on fuel synthesis. If electricity becomes “free” for hours a day, even crummy roundtrip efficiency seems like a great option to soak up extra capacity and get long term (seasonal?) storage.

Can you run fuel synthesis profitably purely on intermittent renewable power and scale up and down in real-time?

Capital costs are high and utilization will be low.

The key is sufficiently cheap electrolysers. They are below $300/kW now. The other steps (if any) have higher capital cost/energy cost ratios, so they can be done when energy is more expensive.

Can you explain how the costs pencil out?

Today, in Finland, renewables produced between 0,2 GW and 1,5 GW.

Does that mean I would need $450M (1,5 GW * $300/kW) in electrolysers to soak up all that power?

For simplicity's sake, let's say output averages 1GW over 24 hours? What do I get for the day with my $450M electrolysis plant?

There's a tradeoff between the cost of excess solar/wind and the capacity factor of the electrolysers. You can get a handle on where the tradeoffs lie by looking at optimizations using historical weather data.

https://model.energy/

For Finland, the 2030 assumptions number (for "synthetic baseload" from renewables + storage) is just under their "EPR" number (which may be a bit optimistic, given your experience with an EPR). As I said, Finland is a tough case for renewables. The solution has > 400 MW each of solar and wind, and 110 MW of electrolysers (to provide 100 MW of synthetic baseload).

That's a very interesting site.

I got Average system cost [EUR/MWh]: 101.9 which is more than nuclear, when solving for renewables + storage + hydrogen.

As I said, Finland is one of the worst locations for renewables. There, nuclear remains at least within spitting distance of being competitive.

But as I also said elsewhere in these comments, this just means Finland (and other nearby countries at high latitude and without good wind resources) will become energy ghettos. They will lose their energy intensive industries. You will not be able to compete in such industries with countries where solar seasonality is low and insolation is very high. This means your energy consumption per capita will be depressed. Can a nuclear industry survive powering a handful of such disadvantaged countries? Maybe they'll just import energy from elsewhere (hydrogen can be piped like natural gas; while it has less energy per unit volume it also has considerably lower viscosity, reducing pumping costs.)

Sort of. Doing that would still be cheaper than nuclear power whose capital costs are insane. Does that count as profitable?

It would be cheaper still to throw pumped storage and batteries into the mix.

> Sort of. Doing that would still be cheaper than nuclear power whose capital costs are insane. Does that count as profitable?

Yes. What do I get for $15B? How many GWh of storage and electricity generation?

> It would be cheaper still to throw pumped storage and batteries into the mix.

What pumped storate? Everybody is already about maxed out on hydro capability.

What batteries? The world is barely producing enough for EVs and other stuff, there aren't enough GWhs available for utility storage.

> What pumped storate? Everybody is already about maxed out on hydro capability.

You are making the common mistake of assuming pumped hydro must, like primary hydro, be built on rivers. But pumped hydro just requires two reservoirs near each other with a vertical offset (although one can imagine repurposing an existing on-river reservoir by adding a separate off-river reservoir nearby at a different altitude; any reservoir with a sizeable hill nearby would do.) They could be built anywhere that isn't flat, even in deserts.

This web site uses geographical data to find PHES opportunities around the world. The possibilities are enormous.

https://re100.eng.anu.edu.au/global/

As an example, here's a facility being built near Ely, Nevada. Look how arid the area is. This facility is sized to provide 1000 MW of output for 8 hours.

https://www.powermag.com/major-pumped-hydro-storage-project-...

> What batteries? The world is barely producing enough for EVs and other stuff, there aren't enough GWhs available for utility storage.

You are again making a foolish argument that production of things cannot be increased. Please stop. One would almost begin to think you're arguing in bad faith here.

You are describing e-fuels. Hydrogen from excess renewables is the same idea. The critics are simply not paying attention to the fact that green energy is nearly free and therefore fuels made from it can also be nearly free.

The plants aren't free.

Same issue with wind and solar. Sure, you have to build them first, but afterwards it's a continuous stream of virtually free energy.

How much is virtually free?

How much will each kWh generated from synthetic fuels cost?

As free as green electricity itself. You're just reusing the same attacks that were used against wind and solar.

Asking questions is attacking, now is it? What are we, snowflakes?

Can you please answer the question with dollars and cents? Or if you don't know, say so.

Green electricity isn't free. Neither will synthetic fuels be.

Is green electricity suppose to be nonviable now? If you can accept that green electricity, which will be the dominate source of unexpected cost, is going to be very cheap, then anything predominately made from it will also be very cheap.

This is a repeat of the anti-wind and solar attacks because it is the same general principle. Basically an appeal to the unknown that the new green technology couldn't possibly be cheap, despite plenty of evidence that cost is dropping or that there is no expensive supply chain.

"Combustion turbines for 100% hydrogen are not commercially available today."

https://www.lazard.com/research-insights/levelized-cost-of-e...

How are you going to use hydrogen to generate electricity without generating CO2 and other emissions?

How are you going to make e-fuel or other synthetic fuels cost effectively? Even if electricity is free, the plants aren't.

Industrial combustion turbines have been available for decades that burn hydrogen (in waste gases from various industrial processes, and also in jet engines adapted to burn hydrogen). It's just a matter of designing a combustor that works with the gas. This is known to be a solvable problem. If a particular high end gas turbine that's available today doesn't yet have a hydrogen combustor, that just means this solvable problem has to again be solved in this case.

How is your comment different from:

"Combustion turbines for 100% hydrogen are not commercially available today."

It rejects the insinuation that this is somehow an obstacle to using hydrogen burning turbines in the future.

And that insinuation is there, or else why did you bring that up?

> It rejects the insinuation that this is somehow an obstacle to using hydrogen burning turbines in the future.

There is no insinuation, it's just a statement of fact. Combustion turbines for 100% hydrogen are not commercially available today. We literally cannot burn 100% hydrogen at scale to provide utility power today.

We may be able to do so in the future, which would be great. Even better if we can do so without emissions and cheaper than other alternatives. But we cannot do so today.

Siemens thinks we can do 100% combustion turbines in about a decade or so. Time will tell. There may be obstacles or maybe everything goes swimmingly.

> And that insinuation is there, or else why did you bring that up?

I brought it up because it is a pertinent detail.

Hydrogen is touted as being the solution to storage for renewables. We are still far from that.

According to https://model.energy/ it might not be such an affordable solution. And even with 100% hydrogen combustion turbines there is the question of storage. Salt caves are cheap, steel storage tanks aren't.

Theyre not commercially available because theres no market for it not because theres anything infeasible about it - cost-wise or otherwise.

The amount of deployed solar and wind around the world isnt even enough to turn off the gas turbines during the sunniest windiest days yet. Theres little point to electrolyzing gas into existence until it routinely overproduces and beyond existing storage capacity and by a lot. Needing to close that 3% gap? That'd be a good problem to have.

And then, there is little reason to burn that gas in turbines until existing consumers of hydrogen (like ammonia plants) have had their fill of it. Even before it's used in turbines, it would operate as dispatchable demand. And when it's used in turbines, it will be mixed with natural gas at first. Below about 20% H2 existing combustors work fine.

To solve the emission problem we need to be able to turn 100% hydrogen in to electricity.

Yes, and this is possible, and has been done before. The point I was making is that it's not necessary to do it immediately. There are intermediate steps where it isn't necessary.

So, it's a solved problem? There are prototype/experimental 100% hydrogen combustion turbines?

Yes

https://www.ge.com/gas-power/future-of-energy/hydrogen-fuele...

I would humbly suggest that in future you try to avoid using rhetorical questions to make a point when the rhetorical question can be answered by google.

The fact that these rhetorical questions carry what appears to be a distinctly anti environmental agenda doesnt exactly make this incuriosity better.

> I would humbly suggest that in future you try to avoid using rhetorical questions to make a point when the rhetorical question can be answered by google.

It was not a rhetorical question.

Furthermore the first hit on Google is:

"GE, DOE Accelerating the Path towards 100% Hydrogen"

The rest of the results are various reports of testing, research and trials.

None of these refute the original quote from the 2023 Lazard report:

"Combustion turbines for 100% hydrogen are not commercially available today."

Neither does the link you provided, which is full of weasel words.

As such 100% hydrogen combustion turbines very much do not seem to be a solved problem. I will concede that there appear to be some prototype/experimental 100% hydrogen combustion turbines, which is great. Still no commercial availability, tho.

Siemens (from the first page of Google results) probably has a more realistic take on the matter:

" H₂ capabilities of our medium-sized gas turbines

As of today, the gas turbines we're testing in our new Zero Emission Hydrogen Turbine Center are ready to burn up to 75% of hydrogen in the fuel mix. And step by step we aim to reach 100% by 2030."

So, perhaps we can agree that 100% hydrogen combustion turbines are an aspirational technology. Something that might come about in the next decade or so.

> The fact that these rhetorical questions carry what appears to be a distinctly anti environmental agenda doesnt exactly make this incuriosity better.

LOL.

I will begin by reminding you of the Hacker News guidelines:

"Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith."

I will continue with noting the we, in Finland, produce about 90% (IIRC) of our electricity without fossile fuel emissions. How are you guys doing?

So you can take your "anti environmental agenda" and do something interesting with it in dark, enclosed spaces.

Sidestepping the incorrect use of "rhetorical", I do wonder what it is about facts and relevant questions that get under the skin of some people?

Is it just the embarrassment of realizing that one's arguments are without merit or the facing one's inability to coherently explain metters?

>The rest of the results are various reports of testing, research and trials.

Right, coz the technology, which exists and is deployed, is being refined before being commercialized at scale ready for the future mass market opportunities that are, as I mentioned, yet to materialize.

>Sidestepping the incorrect use of "rhetorical", I do wonder what it is about facts and relevant questions that get under the skin of some people?

I found it kind of funny actually. The number and nature of questions suggested a high level of ignorance (e.g. this easily googled one) that was coupled with a overtly arrogant attitude. Hoisted on your own petard so to speak ;)

I can't be bothered to answer questions from somebody who uses a deluge of rhetorical questions to argue a covert or overt anti-environmental position in bad faith though. One google to prove you 100% wrong about is sufficient.

Pro tip: try to avoid histrionics about "what to do when the sun doesnt shine and the wind doesnt blow" in future if you want to sound less like a coal lobby pamphlet from 2012 ;)

I strongly recommend you acquaint yourself with a dictionary. Look up "rhetorical". I can suggest other words also.

> I can't be bothered to answer questions

Well, I can't blame you if you don't know or can't articulate answers.

> One google to prove you 100% wrong is sufficient.

Sure, I'll take the bait. What is your one true google then?

> Pro tip: try to avoid histrionics about "what to do when the sun doesnt shine and the wind doesnt blow". its so 2012 ;)

Here's another pro tip: go outside. Observer. You will see and feel that the sun doesn't always shine and the wind doesn't always blow. You can even find occasions when both meteorological phenomenons occur.

Then look at electrical generation charts. Note that both sun and wind production varies. Note that low or zero generation of both occurs.

I mean, this is basic kindergarten stuff. I can't believe I have to spell out the obvious to somebody that can both read and right. Don't know about the comprehension part, tho.

A hilarious thing about his argument is that it also would rule out nuclear.

Existing thermal burner reactors cannot power the world -- the cheap uranium they depend on would run out too quickly. So, one either needs breeder reactors or cheap seawater uranium extraction. And neither of those are available commercially.

> Most seem to think 4 hours qualifies as storage.

It does in some places. In Finland (where I presume you are), it clearly isn't enough, but in warmer places like Texas and California and the huge swathes of the world that have sufficiently reliable renewable electricity resources that 4 hour storage could handle the intermittency.