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Cheap, green hydrogen would be a breakthrough in clean energy

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

#131

Post by Melatonic »

derriz wrote: post #25

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 do…

Couldn't it be very useful for instances where weight to fuel (energy) ratio is very important?

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

#132

Post by Melatonic »

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…

I can see a future where in 200 years we start using it for space travel

Ramjet maybe? Or I forget if that is even hydrogen based at all.

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

#133

Post by Melatonic »

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.

Burning fossil fuels has some pretty big negatives.......

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

#134

Post by osigurdson »

derriz wrote: post #25

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 do…

I think for larger plants the goal is not to store hydrogen in a fuel cell but in a depleted gas reservoir.

https://www.sciencedirect.com/science/article/abs/pii/S03603...

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

#135

Post by sumy23 »

mytwocentsworth wrote: post #130

The second paragraph of TFA passingly mentions liquid fuels, then fails to elaborate. A blockbuster point is thereby deprived of appropriate emphasis. According to Wikipedia[1], "Electrofuels, also known as e-fuels or synthetic fuels, are a type of drop-in replacement fuel. They are manufactured using captured carbon dioxide or carbon monoxide, together with hydrogen obtained from sustainable electricity sources such…

E-fuels don’t do anything other than make the original carbon consumption more efficient. Let’s say you have a coal power plant and capture the carbon to make e-fuel. You’ve made the coal more efficient, as you get the same amount of electricity + fuel, but it’s still carbon positive due to the laws of thermodynamics. E-fuels, while cool, aren’t that promising to me.

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

#136

Post by throw_nbvc1234 »

elihu wrote: post #93
rich_sasha wrote: post #59

Earlier quoted context omitted.

The point is that some countries have long dark winters, often with windless spells. Some are also lowland countries with little or no access to hydro. For green energy, you'd need to literally store months' worth of energy somehow, and the cost of doing that via batteries is prohibitive too. I guess the hope is that storing hydrogen, difficult and expensive that it is, could be made to be more like storing hydrocarb…

Having some cheap long-term energy storage option is one way to solve that problem, but another is better power grid interconnection. For instance, Chicago could get solar power from Chile in the winter time to buffer out the seasonal variability. Or if they didn't even want to have to maintain a smaller buffer to deal with day/night cycles, they could get solar power from, say, Algeria and Australia depending on tim…

How would you factor in Geo-political risks to this approach? Seems like we're trading dependency on oil producing countries with a dependency on "sunny and windy" countries. Arguably worse unless the grid is connected like a mesh. Quick google shows that 61% of oil is transported by sea.

Non-mesh power-grid interconnection is the equivalent of an oil pipeline with the geo-political downsides associated with it. Though maybe the dependency would at least be bi-directional in some instances.

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

#137

Post by UnchartedSystem »

ncmncm wrote: post #110
UnchartedSystem wrote: post #45

[dead]

Guess you mean dimethoxyethane, or "glyme". To "extract bitumen" appears to mean mine tar sands for hydrocarbons. I expect demand for mined oil to decline to the point where only the absolute cheapest producers of it will be able to stay in business. Extracting from tar sand will be right out.

I mean dimethyl ether: DME. Unfortunately, I really doubt we are nearing a collapse in demand for oil. This technology seeks to convert the transportation industry to safe, cheap, and green hydrogen power, but bitumen derived products are used as an industrial feedstock for countless products that make modern society. This technology can reduce the CO2 emissions of extracting and distributing bitumen by 85% - >100%, while reducing the capital costs by 65% - 85%. It allows transitional oil to be produced cheaply, relatively cleanly, and in countries that don't violate human rights or fund terrorists.

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

#138

Post by [deleted] »

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…

[deleted]

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

#139

Post by osigurdson »

ParksNet wrote: post #98
derriz wrote: post #25

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 do…

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.
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