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Iron as an inexpensive storage medium for hydrogen

ethz.ch

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Re: Iron as an inexpensive storage medium for hydrogen

#41

Post by rini17 »

7952 wrote: post #20
w-m wrote: post #15

This seems to be the most important problem to be solved for a green, future grid. So I’m happy there’s a new solution shown every other month. It’s annoying that they always seem to contain some hand-wavy efficiency calculations. I think this one didn’t even consider the losses from hydrogen production? Is there a benchmark out there, of these long-term electricity storage solutions? Like: you get 1 MWh at 25 deg C,…

The focus on efficiency can be short sighted though. The whole point of storage is that the energy you sell is more expensive than the energy you buy. If the profit margin is high enough then you can afford to waste energy through inefficiency. And grids with lots of renewables will naturally have times where energy is cheap and times when it is expensive. Also, I doubt this will exist in isolation. It will probably…

If it has 33% net efficiency that sets it back 3 times compared to batteries right from the outset. With stainless steel pressure vessels needed here and hydrogen precautions, not holding my breath.

Re: Iron as an inexpensive storage medium for hydrogen

#42

Post by samatman »

When I was a child, we would play a game called "the floor is lava". It's a simple game: you have to get around, but not touch the floor. Jumping on the furniture and such. Fine for a pastime, when you're small, but to get places, you use the floor.

A certain faction of the project to decarbonize the electrical grid likes to play a similar childish game: "nuclear power is lava". It causes them to come up with whimsical and absurd epicycles, which make no sense at all unless you're playing that game.

Seasonal storage of 2GWh? Please. A 2GW plant produces 2GWh every hour, with 90% uptime. And it doesn't involve losing more than 90% of the photovoltaic energy, I will eat my whole hat if the ray-to-electricity pipeline for this boondoggle exceeds 10% efficiency.

Can we please stop wasting time and effort, and invest in the buildout of a substantial nuclear fleet to provide baseline power?

Re: Iron as an inexpensive storage medium for hydrogen

#43

Post by HeatrayEnjoyer »

erickj wrote: post #23
johndough wrote: post #10

Earlier quoted context omitted.

I'd like to point out row 3 of the excellent Fig. 6 where the authors evaluate the risk of fine iron powder being exposed to air, which heats up to about 600°C due to oxidation. https://pubs.rsc.org/image/article/2024/se/d3se01228j/d3se01...

I believe most Swiss scientific investigations are legally required to involve Cervelat

What is it?

Re: Iron as an inexpensive storage medium for hydrogen

#45

Post by outop »

londons_explore wrote: post #14
jl6 wrote: post #3

Earlier quoted context omitted.

They mention using waste heat from the reaction to minimize the energy cost of discharge. As long as they still get some power out of it, it could be a win even if it’s quite inefficient. When the input hydrogen is “free” in the summer (due to excess production), inefficiency can be tolerable. I do wonder if “free” will actually pan out, or whether someone will find a way to demand-shift from winter to summer and use…

I suspect in the next 50 years electricity will end up globally transportable via undersea cables, like the internet does for data today. At that point, it's always summertime somewhere and it's always daylight somewhere, and if prices were to fall to zero there is always someone who would like more heat for something. Therefore I suspect zero-priced energy will stop existing.

Isn't it possible that such a system will over-produce 99% of the year and that therefore, the marginal cost will almost always be $0?

'Take my energy and allow me to stop accelerating my flywheels which regulate production' seems more plausible than 'someone would always like more heat for something' (what?)

Or possibly 'take my energy and I'll cut off some of the people using spare energy to do low priority, low value computation for free'?

Re: Iron as an inexpensive storage medium for hydrogen

#47

Post by derriz »

crote wrote: post #38
goodpoint wrote: post #32

Earlier quoted context omitted.

This not a problem at all when using PV. Plus, the generated heat can be used.

The issue is that it's a self-defeating mechanism. PV doesn't produce zero energy during wintertime, they just produce less . You're going to be building additional PV to charge the Season Battery, but those additional panels will also be providing power during the winter. If your battery's efficiency gets bad enough the added winter power from those extra panels is going to be enough to cover the winter shortage - s…

A good point.

Depending on the latitude/weather/etc, the difference between winter PV production can see a reduction of between 40% and 85% compared to summer output (sampling from [0]).

Panel prices have dropped so much, it's far more likely that, at least with places where summer output is double that of winter or less, that simply doubling the number of panels solves the problem.

Batteries and PV are cheap and getting cheaper all the time, are proven and are absolutely trivial to install, operate and maintain compared to ANY conceivable process that involves hydrogen.

I don't get the apparently insatiable drive/impulse that drives people to put so much effort into shoehorning hydrogen into the energy sector. It's expensive, inefficient, dangerous, leaky and is a potent greenhouse gas[1].

The hydrogen idea has been around for over 100 years, has never worked at scale, despite many efforts and large investments. It's time to walk away and concentrate effort into technologies that have actually delivered and have already reduced carbon emissions at scale.

[0] https://pvwatts.nrel.gov/pvwatts.php

[1] https://www.dnv.com/article/is-hydrogen-a-greenhouse-gas--24...

Re: Iron as an inexpensive storage medium for hydrogen

#48

Post by micwag »

rini17 wrote: post #41
7952 wrote: post #20

Earlier quoted context omitted.

The focus on efficiency can be short sighted though. The whole point of storage is that the energy you sell is more expensive than the energy you buy. If the profit margin is high enough then you can afford to waste energy through inefficiency. And grids with lots of renewables will naturally have times where energy is cheap and times when it is expensive. Also, I doubt this will exist in isolation. It will probably…

If it has 33% net efficiency that sets it back 3 times compared to batteries right from the outset. With stainless steel pressure vessels needed here and hydrogen precautions, not holding my breath.

This is for seasonal energy storage with only 1 charge and discharge per year. It competes with water reservoirs not with batteries.

Re: Iron as an inexpensive storage medium for hydrogen

#49

Post by 7952 »

rini17 wrote: post #41
7952 wrote: post #20

Earlier quoted context omitted.

The focus on efficiency can be short sighted though. The whole point of storage is that the energy you sell is more expensive than the energy you buy. If the profit margin is high enough then you can afford to waste energy through inefficiency. And grids with lots of renewables will naturally have times where energy is cheap and times when it is expensive. Also, I doubt this will exist in isolation. It will probably…

If it has 33% net efficiency that sets it back 3 times compared to batteries right from the outset. With stainless steel pressure vessels needed here and hydrogen precautions, not holding my breath.

But there comes a point where battery storage has all been used and prices go even higher. You sell at a x6 profit margin. And are able to sell at x3 profit margin for longer than the battery operators. And that assumes that 100% of the fuel would need to come from storage.
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