Understanding Solar Energy

The author misses a perhaps unintuitive point: the cost of storage depends also on the cost of energy. By the time you've overbuilt 2x, a full extra 100% of your demand is sitting around literally free at odd hours.

Traditionally, moving energy around means batteries, and yes maybe your battery costs more than just generating new electricity from a less efficient new solar panel at odd hours. But batteries are optimized for energy being expensive, where losses are wasteful.

Consider this really simple, dirt cheap alternative: plug your free energy into a pool of water and collect the hydrogen from it. Burn the hydrogen later, and point the light at your idle solar panels. It's hellishly inefficient, but I repeat: the energy is free. You are only minimizing capital costs, at least until other people catch up and start shifting load some other way.

The sane point on this curve probably looks something along the lines of a mix of batteries and synthetic fuels powering existing fossil fuel plants. The nice thing about going all the way to synthetic fuels and not hydrogen is that long term storage becomes trivially cheap, so it starts offsetting your winter load as well.

It's a very long stretch from "generate hydrogen" to "powering existing fossil fuel plants".

The most unlikely part is not even creating renewable fuels (that is a stretch already), but the idea that those fuels are going to be compatible with existing plants and infrastructure. It's not impossible, but it would probably be the least economical way to go about it. I recommend reading some industrydecarbonization.com articles for going a bit more in-depth about the why.

> It's hellishly inefficient, but I repeat: the energy is free.

Can you give pointers about who gives away hydrogen generation systems for free?

Because the cost of energy usually factors in the cost of amortizing equipment required to produce and distribute it.

> The nice thing about going all the way to synthetic fuels and not hydrogen is that long term storage becomes trivially cheap

Once you've financed all of the horribly expensive capital expenditure, and provided you disregard that operating costs actually require paying people to monitor, repair and operate that infrastructure, the rest is basically free.

> Can you give pointers about who gives away hydrogen generation systems for free?

If you don't care about efficiency (because the electricity is free), a 9 year old can make hydrogen generators out of old pencils and jam jars.

Citation: me, I did that.

I can also make some methane depending on what's on the lunch menu, but that doesn't mean cheap renewable natural gas is a solved problem.

Do you really not understand the point I'm making here?

The technical skills needed to make a device that turns water and electricity into hydrogen are so minimal that they can be performed by someone too young for you to be allowed to employ them.

When you don't care about efficiency, hydrogen is trivial.

The limiting factor is how much electricity you can shove through the water, not human effort.

To be fair the problem with hydrogen isn't the production (that is ~free, once you have free energy at least some amount of time) but it's storage and then usage. Storage is a fundamental physics problem. Usage is something where low efficiency may or may not be a problem, depending on the over provisioning that we applied at the generation and storage stages.

Hydrogen-ready power plants are already being built, so that’s actually the least difficult part of the problem. The current bottleneck is actually producing the hydrogen, and next will be building the transport infrastructure.

https://www.latitudemedia.com/news/hydrogen-ready-power-plan...

Production is trivial, but storage and transport really isn't: https://climate.mit.edu/ask-mit/can-we-use-pipelines-and-pow...

Less than 1% of all the hydrogen produced worldwide is from "green" sources [1].

If your dirt cheap alternative is really so dirt cheap, why doesn't anybody do it?

[1]: https://www.iea.org/reports/global-hydrogen-review-2024/hydr...

first of all, youre spreading misinformation.

storage is CHEAP AF. BUT not kind every misinfo guru from youtube tells you about.

this is cheaper - https://ethz.ch/en/news-and-events/eth-news/news/2024/08/iro...

also https://www.rotterdaminnovationcity.com/co2-neutral-living-i...

AND most importantly, WHY do you need to transport hydrogen ? You do not need. think about it. you get electricity to your plant, make hydrogen on site, store hydrogen on site for almost nothing. why do you need to transport anything ? you do not.

Oh wow. I read about that project some time last year. But I didn't do the calculations back then. If I did my math correctly then this H2-in-iron comes out to 2EUR/kWh_el. I wonder what the catch is

We don't yet live in a world where electricity is reliably overproduced by 2x. Renewables are ~100% of the US's new electricity production, but still only a small fraction of its total electricity production.

Hydrogen generation systems exist on the same balance. When the input electricity is expensive, you want to build them to be more efficient, and that costs money, in catalysts and low-loss reaction chambers and such. If a huge amount of energy at peak times is free, then the optimal point is very different, and indeed if you try to minimize capital costs you end up needing something barely more sophisticated than a kettle. Kettles aren't particularly expensive to run!

While competition will quickly drive this towards a more even balance, as cheap storage displaces yet-more excess solar buildout, the point of the argument was just to show why naïvely extrapolating to extreme overproduction (>2x) is misleading.

Storage matters for widespread direct-consumer use of hydrogen, but in the example I gave it's not a big deal: just put the electrolyzer next to the solar panels. You only need to store ~12h of hydrogen production, and burn it onsite.

A more realistic world won't be implementing the Dumbest Possible Refutation, and would overbuild solar less than this in the first place. In that case you do care a lot more about storage, and that's a large part of why I suggested ‘synthetic fuels powering existing fossil fuel plants’ would be a saner strategy. But what exactly that world looks like is in the details, and not critical to the broad point I was making.

Interesting references, thanks. But both seem to be at the research and feasibility stage. From the ETH group's web page: (https://fml.ethz.ch/research/ses.html)

> To demonstrate the technical feasability of this process, we buildt a 10MWh pilot plant at ETH Hönggerberg. The first charing cycle, using hydrogen to reduce iron oxide to iron, was successfully completed over a time span of 4 months. The discharging cycle is currently ongoing.

So either they haven't managed to do a full cycle yet, or they are not updating their research page. It sounds like this should work, so I'm tentatively optimistic. But this looks like a technology you'd have to bet on, not yet a certain path to a commercial seasonal battery just waiting for mass deployment.

ETH zurich is not inventing new reaction, google "reducing iron oxide by hydrogen". it is well known and already used technology. nothing new about this reaction, way they use it is new. all your concerns are answered in next article :

another university - university of eindhoven is using same reaction but totally different way - they just burn iron oxide in air ... https://www.youtube.com/watch?v=Qm0sIN-KhUo same thing same people - https://newatlas.com/energy/bavarian-brewery-carbon-free-ren... it is just totally primitive way and THAT is actually benefit. because it can be deployed fast and wide.

people seems to not understand how big of a energy demand is for hot water. and this can make hot water from renewable sources a reality. in most houses hot water need is roughly 50% of energy need. in low carbon houses / LEED / BREAM /Passive house / or what EU regulations already require, is energy need for hot water multiples of all other energy needs of household, because with better houses, youre lowering energy required for heating, cooling, but hot water stays same amount but bugger percentage.

planetary - with better buildings, we can lower house heating by 70-80 % no price problem, hassle free, that means we need less electricity generation for houses. + adding hydrogen generation / iron oxide reduction into mix we can just burn it and make hot water and electricity in winter from spring, summer, autumn sun.... in spring,summer,autumn you use PV for hot water + hydrogen to store for winter. booom 95+% of household consumption is gone from grid. household energy need is how much of total planetary energy need ? 20 or 40 % ? no one cares.

you do not need to transport anything if you think about this as for seasonal storage. but you can transport raw iron like university of eidhoven is proposing if your mission is to provide heat but reduce iron oxide close to renewable generation. your tansporting iron (Fe), NOT iron oxide(FeO,FeO2,FeO3)...

how much of kWh is your house needing for heating, hot water and how much for tv,notebook etc ? calculate what percentage / ratio your tv is. caring about electricity is nonsense, care about 95% of your household consumption. and yes your cooling bill is 0 dollars because you have PV on roof.

> youre spreading misinformation

> every misinfo guru from youtube tells you

Please don't cross into personal attack in HN comments and please edit out swipes and name-calling. Your post would be fine without those bits.

If you'd please review https://news.ycombinator.com/newsguidelines.html and stick to the rules when posting here, we'd appreciate it.

> Do you really not understand the point I'm making here?

This is the sort of thing that the site guidelines ask you to edit out of your comments here (https://news.ycombinator.com/newsguidelines.html). Your post would be just fine without that bit.

youtuber - it is not personal attack it is commentary on state of world, im saying to him that he should recalculate, review information he gets from youtubers.

every youtuber who says hydrogen storage, transport is not cheap is spreading misinformation. or if youre angry because you know youtubers are saying it because it as a desinformation, then feel free to chime in about it. or report those youtubers directly inside of a youtube platform.

not personal attack, i am not cute, i am not smart. they are saying nonsense. i provided links showing price for transport, storage is orders of magnitude lower than what any of top 50 science youtubers are saying it is.

you can correct previous statement by providing link for any video of any top 50 science youtuber providing correct numbers.

I meant "misinfo guru" in that case, especially because you directed that at the other person ("tells you").

You don't need to say things like "they are saying nonsense" - it's enough to provide correct information that addresses incorrect information.

but he will just go back to youtube. that is why i need to say youtube guru is wrong to make clear what exactly is harmful.

Oops, noted.