Cheap, green hydrogen would be a breakthrough in clean energy • Hacker News Board

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#231

Post by ParksNet » Wed, Jun 22, 2022, 6:08 PM UTC

osigurdson wrote: post #139

ParksNet wrote: post #98

Earlier quoted context omitted.

If we want to be serious about grid storage, look to the gigantic fleet of EVs we're building out. All of those vehicles should be able to charge and discharge to the grid based on daily demand and user preference. I'm looking at buying a base Model 3. Huge (57.5 kWh)chunk of battery that will be sitting there most of the week (wife and I both work from home). Charging at 40c/kWh during the day (from abundant solar)…

I would think that EVs would largely be a net load on the grid at night since that is when they would normally be charged. It could possibly be a revenue source for those with non-standard usage patterns of course.

Here's California's energy usage by hour from 2017:

https://www.researchgate.net/publication/341393321/figure/fi...

We need some kind of alignment between Electricity producers / the Grid, and EVs / manufacturers.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#232

Post by ncmncm » Wed, Jun 22, 2022, 6:31 PM UTC

kkfx wrote: post #230

ncmncm wrote: post #218

Earlier quoted context omitted.

Let's make a game: you collect actual figures instead of just making shit up.

Ok, from a conference not much time ago I've noted, but unfortunately fail to recover linkable reference, around 67kWh to extract 1kg of H₂ if there are no losses in the process. I can't estimate losses but I can imaging are there in a relatively relevant percentage. The there is the storage issue: H₂ goes trough essentially any tank, no matter how we store it in practical ways, and that's another loss hard to be com…

You imagine that hydrogen cannot be stored, yet we handle tens of millions of tons every year. Do we vent it and then gather it from the air when we need some? No, we store and transport it. Some is stored in underground cavities, places where we put NG today. Some is liquified. Some is in, yes, tanks at 700atm.

You can buy electrolysers on the open market, cash on the barrel head. Need more hydrogen? Buy more electrolysers. Where does this fail to "scale"?

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#233

Post by Sinidir » Wed, Jun 22, 2022, 6:51 PM UTC

ClumsyPilot wrote: post #223

ZeroGravitas wrote: post #213

Earlier quoted context omitted.

Because it piggybacks on the political might of fossil fuel producers who are subsidized by taxpayers and don't have to pay for their externalities. It's not "cheaper" for a mob connected waste disposal firm to dump waste into a river. If they were prosecuted for the damage they did to other people's property and had to pay for the damage they did then they'd need to raise their prices to the point that just dealing…

So whats the best case possible efficiency?

https://www.sciencedirect.com/science/article/pii/S187661021...

This is a nice paper on the different fuel cycles of hydrogen ammonia and methyl.

Roundtrip efficiencies for hydrogen and ammonia are both at about 30% plus. Don't know how high it could theoretically go.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#234

Post by ncmncm » Wed, Jun 22, 2022, 6:58 PM UTC

arbol wrote: post #21

phkahler wrote: post #13

Earlier quoted context omitted.

Quoted post unavailable.

I was confused by this comment until I read this: https://www.weforum.org/agenda/2021/08/hydrogen-carbon-inten...

Point is that it is hard and anyway probably unwise to divert renewable power to hydrogen synthesis from things that are using the electricity without conversion losses. It is just about as good or bad to burn NG making hydrogen as to burn NG to make electricity.

But once we have got renewable overbuilt, all the math changes. Until then, unquestionably the right place to spend capital is building out renewables. Building up hydrogen infrastructure, in the meantime, and even fueling it with gray hydrogen, is OK provided it doesn't cost money that could have gone to renewable generating capacity instead.

Often capital has strings attached, and can't go for renewables. Then, spending on readiness to use the coming, cheap hydrogen or ammonia (and burning gray fuel for now), or generally on energy storage, is better than most choices.

Thing is, money is fungible. Each dollar goes to one place and therefore not another. Energy is too, albeit with conversion losses. So, green hydrogen and NG electric is no better or worse than gray NG hydrogen and renewables. Anywhere we can displace NG entirely is good. Moving use of it around, much less so.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#235

Post by ncmncm » Wed, Jun 22, 2022, 7:17 PM UTC

wh33zle wrote: post #49

bbojan wrote: post #29

Earlier quoted context omitted.

Water electrolysis is around 60-80 percent efficient. Hydrogen fuel cells are around 40-60 percent efficient. Plus you spend additional energy to either compress or cool the hydrogen in order to be able to store it. Electricity storage in a lithium-ion battery is on the order of 98% efficient, and electric motors are around 90% efficient (if you take into account the whole drivetrain).

Thanks! Although it seems like these numbers can be improved [0] and are not fundamentally linked to the technology. [0]: https://newatlas.com/energy/hysata-efficient-hydrogen-electr...

Yes, hydrogen and ammonia handling efficiency will mostly go up, unless extra-cheap (to buy) electrolysers come out with unfortunately lower efficiency.

What always matters most is cost. Inefficiency will get cheaper and cheaper as generation cost falls. Switching from gold & platinum catalyzing electrolysers to something not dependent on those and less efficient is still a win if you get a lot more electrolysers for your money.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#236

Post by kkfx » Wed, Jun 22, 2022, 7:53 PM UTC

ncmncm wrote: post #232

kkfx wrote: post #230

Earlier quoted context omitted.

Ok, from a conference not much time ago I've noted, but unfortunately fail to recover linkable reference, around 67kWh to extract 1kg of H₂ if there are no losses in the process. I can't estimate losses but I can imaging are there in a relatively relevant percentage. The there is the storage issue: H₂ goes trough essentially any tank, no matter how we store it in practical ways, and that's another loss hard to be com…

You imagine that hydrogen cannot be stored, yet we handle tens of millions of tons every year. Do we vent it and then gather it from the air when we need some? No, we store and transport it. Some is stored in underground cavities, places where we put NG today. Some is liquified. Some is in, yes , tanks at 700atm. You can buy electrolysers on the open market, cash on the barrel head. Need more hydrogen? Buy more elect…

I imaging hydrogen can be stored, but not for long, witch means we store it and slowly it "evaporate" going through the tank.

BTW let's talk about an example: Toyota Mirai, far complex than an EV, complex than an ICE, ~1kg H₂ / 100 km. Now let's say we have spend 67kWh of green electricity to produce that kg of H₂, the process have some loss, again I can't really know how much but some [1] say are around 14%, not bad but still a certain amount of loss. Than the energy need to compress resulting gas to 700 bars. Energy to push it in the car tank. At the end of the game you get what? 33-34kWh out of initial 67?

100 km? A Tesla do 100 km with around 18kWh... Surely and H₂ fuel-cell system have far more power than a lithium one, around five time per similar size/weight, so we can potentially power trucks, even planes with hydrogen, while we practically can't [2] with lithium.

Again trying to imaging a possible hydrogen-based vehicles scenario we end up in far cheaper "energetically speaking" blue/grey hydrogen but what's it's point? We can burn directly hydrocarbons, we already use them. Using them to make hydrogen means just spent a lot for a new supply chain and just shift pollution outside citizens sight. With the benefit of running on 700 bars bombs under our asses...

[1] https://mdpi-res.com/d_attachment/materials/materials-12-019...

[2] yes I know eVTOL experiments, they can't scale behind such kind of very expensive personal toys with lithium chemistry for energy source

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#237

Post by clouddrover » Wed, Jun 22, 2022, 9:40 PM UTC

taneq wrote: post #228

clouddrover wrote: post #104

Earlier quoted context omitted.

> Hydrogen is supported only to draw support away from EVs. I always find this false hydrogen versus batteries narrative bizarre. Hydrogen fuel cell vehicles are EVs. It isn't an exclusive choice between hydrogen or batteries. Choose both hydrogen and batteries, both FCEVs and BEVs. In any case, if you want your EV to be manufactured with green steel then you want hydrogen to be used in the production of that steel:…

The hydrogen-is-the-enemy-of-EVs thing comes from the way that car manufacturers in the '90s pushed hydrogen as the "fuel of the future" in order to stall the CARB EV mandate from interfering with their ICE car sales. It was a cynical bait-and-switch where they simultaneously insisted that it was impossible to build acceptable BEVs (despite both the GM EV1 and the Rav4-EV being universally lauded) and extolled hydrog…

That doesn't seem very likely. Nissan was mass producing EVs before Tesla:

https://en.wikipedia.org/wiki/Nissan_electric_vehicles

The hydrogen conspiracy theory doesn't make any practical sense.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#238

Post by rstuart4133 » Wed, Jun 22, 2022, 10:22 PM UTC

Barraketh wrote: post #52

Ammonia has been mentioned a few times in this thread, but I will expand a bit, because I believe it is the most promising hydrogen-based approach. Essentially, the idea is to use ammonia directly as fuel. There is an ARPA-E funded project (that I'm currently failing to find) that cracks ammonia into hydrogen and nitrogen using heat. They claim that they can create a mixture of H2 and ammonia that will burn at any re…

Are you referring to this: https://www.csiro.au/en/research/environmental-impacts/fuels... ?

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#239

Post by rstuart4133 » Wed, Jun 22, 2022, 10:36 PM UTC

craig1f wrote: post #2

It would. Yet there is no promising tech in this field. Hydrogen is supported only to draw support away from EVs. If hydrogen becomes inexpensive to produce, it will by by way of solar power used to generate it. It will never be easy to store. Hydrogen is the smallest element, and can move through solid objects over time. It is violently explosive. You think these EV fires you see all the time are bad? They're nothin…

> Hydrogen is supported only to draw support away from EVs.

No, or at least not by everyone. Hydrogen is seen as a replacement for natural gas. For example: https://reneweconomy.com.au/australia-japan-consortium-explo... There is no fancy fuel cell converting it to electricity in this plan. They are just going t burn it for heat, just as they do for natural gas.

Now there are a few problems, such as cost. Producing hydrogen costs around 4 times what it costs to produce natural gas. Or at least it did before the Ukraine broke out. Right now, if anyone was making renewable hydrogen, they would ge getting a tidy profit.

Another is storage. You can't economically liquefy it, it literally passes through metal walls and damages them on the way through. Converting to Ammonia is well understood, but getting hydrogen back was a problem. Until: https://www.csiro.au/en/research/environmental-impacts/fuels...

It might work. 100's of millions are being invested into finding out if it does.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#240

Post by ncmncm » Wed, Jun 22, 2022, 10:57 PM UTC

kkfx wrote: post #236

ncmncm wrote: post #232

Earlier quoted context omitted.

You imagine that hydrogen cannot be stored, yet we handle tens of millions of tons every year. Do we vent it and then gather it from the air when we need some? No, we store and transport it. Some is stored in underground cavities, places where we put NG today. Some is liquified. Some is in, yes , tanks at 700atm. You can buy electrolysers on the open market, cash on the barrel head. Need more hydrogen? Buy more elect…

I imaging hydrogen can be stored, but not for long, witch means we store it and slowly it "evaporate" going through the tank. BTW let's talk about an example: Toyota Mirai, far complex than an EV, complex than an ICE, ~1kg H₂ / 100 km. Now let's say we have spend 67kWh of green electricity to produce that kg of H₂, the process have some loss, again I can't really know how much but some [1] say are around 14%, not bad…

Let's not rely on your imagination.

Hydrogen is stored. The amount that leaks can be as small as you like. Actual loss as a percentage of what you put in is always negligible. The point often made about leaks is just that H2 must not be allowed to accumulate, so needs positive airflow to prevent detonations.

Mirai is just an electric car with an H2 tank, a fuel cell, and a small battery. The fuel cell has no moving parts: H2 and air go in, power, H2O, and N2 come out. Mirai is very light, so takes much less energy to muscle around than a battery car. Its small battery is to use while the fuel cell heats up, and maybe to absorb some kinetic energy braking.

A battery electric car is much more complex. It needs to manage charge and temperature on all its cells, use braking to recover and store kinetic and downhill energy to try to extend range. The battery is expensive.

But energy is fungible. After there is plenty of renewable generation capacity, hydrogen made from renewables has not cost anybody anything tangible. Until there is plenty of renewables, making hydrogen costs NG, so will not happen much.

Cars will have batteries. Trucks will probably run on ammonia. Aircraft will run on LH2. The kWh that goes into a unit of H2 will not matter much, because it is just sunshine and wind. We need to get there by spending on renewable generating capacity, first.