The last I read into Germany's plan to be "100%" renewable, it was using other countries in Europe to provide the base load using their hydro and nuclear. Which is great so long as they have excess to provide Germany I suppose.

There does not seem to be nearly enough construction of pumped storage or battery to cover the unevenness of German wind power. In fact, their prices have gone negative repeatedly in the past, which is not in fact a good thing. (OMG help, we'll pay anyone to take this power before the grid blows up!)

It would be stupid to spend on storage before there is enough renewable generating capacity to charge it from. In the meantime they spend, sensibly, on renewable generating capacity.

By the time there is enough, storage will be massively cheaper. In the meantime, charging storage from gas or coal and then drawing it down is the same as burning gas or coal for immediate use, just with losses.

The storage should be built in conjunction with the renewable generation to avoid those excess grid damaging events which is just wasteful. Similar issue to US where constructing generation is being subsidised but not constructing storage along with it.

There are no "grid damaging events".

Correct, because they price it negatively to avoid that happening. It's still indicative of a problem.

Batteries will probably be cheaper, but pumped hydro storage will probably cost about the same since it's a mature technology.

I could see Norway or Switzerland being major players in pumped hydro storage, given their geography.

Awhile back I did a bunch of math to try to figure out how much stored gravitational energy is in Lake Mead, and if I didn't make any major mistakes it came out to be about as much energy as the U.S. uses (as electrical energy) in 24 hours. The idea of moving that amount of water around on short time scales is hard to fathom.

The overwhelming majority of storage will not be batteries, unless a massively cheaper battery chemistry takes over.

Lake Mead stores (well, stored) radically less energy than mountaintop reservoirs with thousands of feet of "head" can hold behind cheap earthen dikes. Look up "penstock".

I suppose I should have clarified that I meant "lake Mead if at capacity" which it isn't.

Stored energy (in a fixed gravitational field) is the product of height and mass. Hoover dam has a "hydraulic height" of 576 feet according to a government website, though the average height of any given drop of water is less than that because the lake is deep (or it was, anyways).

The thing about lake Mead is that the volume of water is absolutely huge. I don't think there are any mountaintop reservoirs anywhere close to it because though the altitude difference could be a lot more, it's hard to store large amounts of water on a mountaintop.

If we estimate that the average height of water in Lake Mead is 400 feet and it holds 26 million acre feet, then a pumped hydro storage system with 4,000 feet of altitude difference would need to hold 2.6 million acre feet to be equivalent. I'm pretty sure there's nothing like that in the U.S. The Bath County Pumped Storage Station in Virginia has an upper reservoir of about 35.6 thousand acre feet and a vertical distance of 380 meters (1,246 feet).

There are dozens of such reservoirs in the Sierra Nevada range in California. None of them will take as much water as Lake Mead, but they don't need to.

The cost of batteries is actually rising, now that manufacturing costs only make up ~25% of a battery's cost [1]. The remaining 75% is raw materials, dominated by the cathode and anode, which are having trouble keeping up with demand [2].

1. https://www.visualcapitalist.com/breaking-down-the-cost-of-a...

2. https://www.cnbc.com/2022/05/18/ev-battery-costs-set-to-spik...

The cost of batteries is immaterial to anything being discussed here.

As you already knew l.

From the previous comment:

> Batteries will probably be cheaper,

The above commenter clearly thinks that batteries are going to provide cheap storage.

If you have some alternative plan for storage at the scale of tens of terawatt hours, please do tell.

It has been explained to you numerous times already.

Trolling is unwelcome here.

So just to make sure I'm understanding you: you insist that storage is a solved problem. It's solution is so obvious that anyone who doesn't agree it's an easy problem is trolling. But on the other hand, you are unwilling to mention how grid scale energy storage in a majority renewable grid will work.

It has been explained to you numerous times already.

You may repeat your lies as much as you like. I will point out that you are lying, each time.

Who do you imagine you are fooling?

you are the one trolling, claiming that a mature technology of hydroelectric dams will get chesper, and making various disingenious argunents like insenuating there are magical locations where oceans of water can be stored at the peak of mount everest

Who do you imagine you will fool?

I'd imagine we'll probably continue to store power the same way the vast majority of power is stored now, using pumped hydroelectric storage.

Pumped storage is geographically limited: as more convenient sites are developed, viable locations become more and more remote. Hydroelectric storage is great, but not the pumped kind. The energy storage supplies by the Hoover dam, the Coolie dam, dwarf pumped hydro.

It's great for countries that have it, but you're not going to be storing much hydroelectricity outside of mountainous regions.

Pumped storage is not, in fact, geographically limited. There are very few places without any hills nearby. There is absolutely no shortage of hills.

Which you knew, if only because it has been pointed out to you numerous times.

But you prefer to repeat your lies, hoping no one will call attention to them.

Pumped storage requires a nearby hill with a lake on top of it (otherwise earth and concrete has to be poured to form an artificial reservoir), and a nearby lower reservoir, and a nearby source of water. And if it isn't close to transportation infrastructure, building a facility becomes prohibitively expensive. As the optimal sites are developed, less and less suitable sites need to be developed.

Why is New York building battery storage at $567/KWh [1] if pumped storage is so cheap?

There a vast amount of hydro storage potential in the Himalayas, but good luck developing any of it.

1. https://www.utilitydive.com/news/new-york-battery-storage-co...

It has already been explained to you numerous times that the above is false. Who do you imagine you will fool this time?

Edit: I've taken a closer look at your recent comments in other threads and it turns out you've been breaking the site guidelines so frequently and so aggressively that I've banned your account.

If you don't want to be banned, you're welcome to email [email protected] and give us reason to believe that you'll follow the rules in the future. They're here: https://news.ycombinator.com/newsguidelines.html.

---

Original post:

Would you please stop breaking the site guidelines? You've been posting tons of unsubstantive and flamebait comments and even (as here) crossing into personal attack. Besides being the sort of thing we ban accounts for, this has the disadvantage of discrediting your own view, which is a bad thing if you happen to be right.

If you'd please review https://news.ycombinator.com/newsguidelines.html and stick to the rules when posting here, we'd appreciate it. We've had to ask you about well over a dozen times in the past, which is not cool.

Edit: you've posted over 80 comments in this thread alone- most of them flamewar comments. That's extreme. Please don't do anything like that on HN again, regardless of how wrong someone else is or you feel they are.

Edit 2: you've been breaking the site guidelines badly in other threads recently too. As I said, we've warned you many times. If you keep it up we're going to have to ban you, so please fix this. It's seriously not ok.

This was definitely the right call.

> we'll pay anyone to take this power before the grid blows up

that's not how that works.

also:

Dunkelflaute is 0.5% - 1.5% per year and only very rarely for longer than 24h. peaker power plants are turned off most of the time today and a combination of those and decentralized battery storage will easily buffer Dunkelflaute in Germany.

https://en.m.wikipedia.org/wiki/Dunkelflaute

In fact, many believe that storage as hydrogen shows promise. There are many test plants for this right now in areas with a lot of wind and connection to the national gas grid.

The idea is that the hydrogen can then be used in existing gas power plants.

Hydrogen is one of many practical storage media. Many will be used, different ones favored in different places. Hydrogen is particularly suited for places with large, stable underground cavities.

hydrogen has a relatively poor efficiency compared to battery storage electricity to store and back, and it's an highly flammable, infamously explosive gas. but it has a high energy density and it can be transported relatively well. hydrogen will find it's niche.

How exactly will you be 100% renewable during a cloudy and windless period with solar and wind?

Trolling is unwelcome here, thank you.

The comment you are replying to was not "trolling"; it raised a legitimate, technical objection to a policy in a manner that invites constructive responses (for example, "with storage technology" is a common response I see).

It is trolling because the answer -- storage -- is well known to anybody who cares enough to do the most shallow of research. So, everyone left is a troll.

Then it'd be good to mention what this storage mechanism is, and examples of existing commercial deployments said storage mechanism and their cost history. It's odd to see someone insist that the solution is so obvious that anyone who doesn't recognize it is trolling, yet they neglect to mention what that solution is.

Storage is a common answer, but it has problems of its own. Presumably the OP considers these problems fatal; if you disagree, say so and explain why.

OP could explain why they imagine fatal problems. Would, if they were not just trolling.

Intermittency is one of the most difficult parts of building a majority renewable grid. Dismissing the biggest challenge in building a renewable grid as trolling is not a good look.

Intermittency is not, in fact, a "serious problem", because simple technical measures mitigate it.

Only trolls insist it is "difficult", to suit their agenda.

All this has been explained to you numerous times. Your trolling is no more welcome this time than any dozen previous times.

> because simple technical measures mitigate it.

And what simple technical measure mitigates it in a cost effective manner? Hydroelectricity is one, but it's geographically dependent. Sweden already has about 30% of it's electricity coming from dams, but it still needs to built more nuclear plants to fulfill it's demand. And most countries have even less hydroelectric generation than Sweden.

Besides hydroelectricity, there's batteries which are not able to be built at scale. Then there's experimental solutions like compressed air, chemical storage, or giant flywheels. But none of those have been deployed commercially and thus there's no real-world cost history.

Proclaiming that the solution is simple, yet neglecting to actually specify it is not an effective way to make the case for storage. If you want to make the case for a plan to provision storage, make it and we can discuss that. But apparently, the solution is apparently so simple it defies explanation. How convenient!

Well in that case: we don't need fission, renewables, or storage. I know of a fusion breakthrough that will make electricity to cheap to meter! And it's so obvious I don't need to explain how it works, and anyone who doubts me is a troll.

You may troll, and, troll, and troll again.

But all know you are lying, this time same as last.

Pumped hydro storage, batteries, and/or long-distance grid interconnection. It's not often overcast in the Sahara, as far as I know, and solar power imported from far to the east and west can mitigate the day/night cycle problem.

It's reasonable to keep ICE power plants around as an emergency backup; if you have to use them for a week in January or when infrastructure breaks for whatever reason it's not the end of the world. Ideally things would run smoothly enough that they'd never be used.

Transmitting energy over long distances is way more difficult than you make it out to be: https://www.youtube.com/watch?v=7OpM_zKGE4o

It'd be expensive, but it's technically feasible. I'd also expect there's economies of scale involved; building a cable with twice the capacity doesn't cost twice as much; you might even just use the same cable and run it at a higher voltage.

Expensive but technically feasible, plus making Europe at the mercy of unstable regimes across the Mediterranean. That worked just fine with natural gas imports from Russia right?

At least Morocco/Algeria/Libya/Egypt/Tunisia don't have nuclear weapons or large conventional militaries and aren't generally much of a threat to anyone but themselves and sometimes their immediate neighbors.

There is a political risk that the governments of those countries change and they seize the energy-producing assets and sell surplus power to someone other than Europe. Perhaps a mutually-beneficial arrangement would be the best way to reduce the risk of it falling apart; for instance, if Morocco has the solar panels and Switzerland has the pumped-hydro storage facility to buffer out day/night cycles, both sides can trade power to their mutual benefit. Without both parts of the whole system, the other half is less useful.

There is absolutely no need to get renewable power from "across the Mediterranean".

Which you already knew, but evidently hoped readers would not.

In case you didn't notice, I originally responded to someone writing:

> It's not often overcast in the Sahara, as far as I know, and solar power imported from far to the east and west can mitigate the day/night cycle problem.

This is not first time in this comment section that you seem to be alleging that I'm bring up irrelevant information, when in fact I am directly addressing something another commenter wrote.

You knew better, but pretended not to.

> It'd be expensive, but it's technically feasible.

So is nuclear fusion. You have provided no evidence or even argument that it is practical.

Proposing that you can compensate day night cycle with transmission is surely a joke, no infrastructure of such scale has ever been built.

Fusion is not, in fact, technically feasible.

Anything not built yet has not been built. After it is built, it will then have been built.

Those things aren't equivalent. Useful nuclear fusion (i.e. more electrical power out than in) has not been demonstrated yet, and probably relies on techniques and technologies that haven't been invented yet.

On the other hand, we know how to make high-voltage DC transmission lines -- the only real questions are: how much will it cost, and is there some way we can do it better and cheaper?

There have already been DC lines over 2,000 miles long built that run at 800 kV or more. That's already long enough to reach several time zones away, and it's not a conceptual stretch to imagine linking several of these together to reach further. According to wikipedia:

> In 2010, ABB Group built the world's first 800 kV UHVDC in China. The Zhundong–Wannan UHVDC line with 1100 kV, 3400 km (2100 miles) length and 12 GW capacity was completed in 2018. As of 2020, at least thirteen UHVDC transmission lines in China have been completed.

> While the majority of recent UHVDC technology deployment is in China, it has also been deployed in South America as well as other parts of Asia. In India, a 1830 km (1140 mile), 800 kV, 6 GW line between Raigarh and Pugalur is expected to be completed in 2019.[58] In Brazil, the Xingu-Estreito line over 2076 km (1290 miles) with 800 kV and 4 GW was completed in 2017, and the Xingu-Rio line over 2543 km (1580 miles) with 800 kV and 4 GW was completed in 2019, both to transmit the energy from Belo Monte Dam. As of 2020, no UHVDC line (≥ 800 kV) exists in Europe or North America.

https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad...

You are assuming geopolitical realities that will... never be reality. The entire issue of Germany's dependence on energy from another country makes this obvious.

You also assume that power plants can just be flipped on and off like a light switch. They can't.

Nobody believes any such thing. Stop putting words in others' mouths.

Which country situated in Sahara would you consider to be stable enough politically, and unlikely to enter in geopolitical alliances that are adversarial to Europe, to place your primary energy infrastructure in?

Deserts are a stupid place to plant solar farms, so the question is moot.

Numerous politically stable European countries have plenty of room for solar installations.

Dunkelflaute is 0.5% - 1.5% of the year and most of the events last shorter than 24h

https://en.m.wikipedia.org/wiki/Dunkelflaute

in my book 98.5% easily fits the bill of "close to 100%"

so the answer is exactly what we do today: have a reserve capacity. part of that may even be traditional peaker power plants that remain turned off most of the year just like today.

I'd be curious about climate data on the distribution of Dunkelflaute duration, by region.

I believe the difference is that during a Dunkelflaute, peaker plants might have to generate a large amount of or the majority of electricity, whereas today, peaker plants are build to only generate relatively small amount of power at the margin.

So, we'd have to build a large number of peaker plants, which are really expensive in that they have to amortize their costs over a small amount of uptime.

short term weather forecasts are amazingly accurate. this allows us to deliberately "extend" the "range" of buffer storage. and even today in some situations some energy intense heavy industries have to pause production for a few hours if there is a lack of energy supply.

It's a political problem, not a technical one, and we do not, absolutely not have to build up new parallel peaker capacity. we can simply keep select plants alive.

Figuring out how much extra capacity is needed still needs to be done.

Simply stating that no new peaker plants are needed "because storage capacity will be there" is a bit too simplistic.

I'd be glad if that's the case, but I'm not convinced it's actually true.

right we have 7 years to figure this out for 80% renewables and 17 years to figure it out for close to 100%

it took 1 year to build and start operation of giga Shanghai, and not much longer for giga Berlin.

it's a political challenge, not a technical one.

Is that the same interview in which she also stood by their decision to rely so heavily on Russian gas, even though the writing has been clearly on the wall since at least 2014?

first that's not what she said. she said given what the cabinet and western intelligence knew they considered it the right approach. and second, in hindsight some writing was on the wall in 2014.

however back then Germany was between a rock and a hard place for our energy supply and we simply added a new supply channel, in addition to US LNG and Saudi and Qatari LNG.

https://youtu.be/yR0wsWrs2yY