Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Cheap, green hydrogen would be a breakthrough in clean energy

gatesnotes.com

Post reply on HN
Print view View original

21–30 of 254 posts

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

#21

Post by arbol »

phkahler wrote: post #13
ZeroGravitas wrote: post #7

> the world will have to get better at balancing energy supply and demand so we don’t go dark when the sun isn’t shining or the wind isn’t blowing. Thanks Bill, that's really helpful, was there really no other way you could have phrased that? > Another option is to produce hydrogen using the current methods that burn fossil fuels and then capture the CO2 produced in the process before it’s released in the atmosphere.…

Quoted post unavailable.

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

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

#22

Post by arbol »

wh33zle wrote: post #15
phkahler wrote: post #13

Earlier quoted context omitted.

Quoted post unavailable.

Can you expand why separation from water is a net energy loss?

Conversion from water to hydrogen via hydrolysis is only 60-80% efficient so it takes more energy to generate the hydrogen than the hydrogen will produce in future.

Source: https://www.weforum.org/agenda/2021/08/hydrogen-carbon-inten...

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

#23

Post by ZeroGravitas »

phkahler wrote: post #13
ZeroGravitas wrote: post #7

> the world will have to get better at balancing energy supply and demand so we don’t go dark when the sun isn’t shining or the wind isn’t blowing. Thanks Bill, that's really helpful, was there really no other way you could have phrased that? > Another option is to produce hydrogen using the current methods that burn fossil fuels and then capture the CO2 produced in the process before it’s released in the atmosphere.…

Quoted post unavailable.

Don't use it as an energy source, see the hydrogen ladder for the sensible markets that we should switch from gray hydrogen to green and the ones we should just electrify directly:

https://www.linkedin.com/pulse/clean-hydrogen-ladder-v40-mic...

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

#24

Post by hnlmorg »

causi wrote: post #18

It's too late for hydrogen. For hydrogen to be green is has to either A) be more green than storing the generating power in batteries and using it from there or B) be created with something other than electricity. It's too late for A, batteries are already too good. As for B), feel free to come up with some kind of metamaterial that can produce hydrogen mechanically and in doing so bypass the efficiency loss of elect…

> For hydrogen to be green is has to either A) be more green than storing the generating power in batteries

I thought batteries had some pretty toxic elements inside them? I don’t know much about using hydrogen as a power source so I’m interested to understand how it’s less green than batteries.

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

#25

Post by derriz »

I don't see hydrogen playing any role for energy storage or grid demand balancing.

Even if all the technical and engineering challenges associated with storing and transporting it safely could be addressed, I just don't see how the economics of green hydrogen is supposed to work. The round-trip energy efficiency of electrolysis-fuel cell is poor - currently about 40%.

The counter-argument is that such inefficiency doesn't matter as it can be used as a sink for excess/almost free renewables (solar or wind) but for this to work, it means leaving your capital-expensive electrolysis plant idle for half or 2/3rds of the day. Since the cost of green hydrogen production is mostly cap-ex not op-ex, this makes the proposition almost completely infeasible.

Looking at the trajectories of grid-scale battery storage and that of hydrogen technology, I don't see how anyone could bet on hydrogen.

The best hope is that we can replace the current industrial consumption of grey hydrogen with that of green but this currently needs massive subsidy as a kg of green hydrogen current costs about 5 times that of gray (admittedly I think the multiple will be less given the current high NG prices).

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

#26

Post by ortusdux »

freemint wrote: post #10

Yeah, so would cheap nuclear power or cheap batteries. I find cheap batteries way more likely then either of those.

Hydrogen is a battery. We have no free source of H2. We have to put energy into making it, storing it, and transporting it. We get less energy back than we put in. The most generous lifecycle analyses that I have seen estimate 60-70% roundtrip efficiency.

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

#27

Post by UncleOxidant »

partiallypro wrote: post #17
freemint wrote: post #10

Yeah, so would cheap nuclear power or cheap batteries. I find cheap batteries way more likely then either of those.

I think the current problem with batteries is that it presents a geopolitical risk that is akin to (maybe worse than) oil.

There are lots of efforts in creating battery chemistries that do not rely on hard to source elements. Lithium sulfur (no cobalt required), Sodium ion (much more readily available than Li), and many other efforts - some showing good results.

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

#28

Post by jxramos »

Is that metal hydride stuff feasible? I heard about it and saw videos around the claims of the substance but was curious why it never took off if it was so great. What are the challenges around it precisely? https://www.energy.gov/eere/fuelcells/metal-hydride-storage-...

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

#29

Post by bbojan »

wh33zle wrote: post #15
phkahler wrote: post #13

Earlier quoted context omitted.

Quoted post unavailable.

Can you expand why separation from water is a net energy loss?

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).

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

#30

Post by [deleted] »

ravenstine wrote: post #20
phkahler wrote: post #13

Earlier quoted context omitted.

Quoted post unavailable.

> separate it from water, which is a net energy LOSS This is true of every form of energy transfer. There is never, ever 100% energy maintained, and maybe you'll be stunned at how inefficient existing energy sources are.

[deleted]
Post reply on HN