Hydrogen Economy - What are the REAL issues beyond the massive hype ?? 5

[MJCronin]

A superb, comprehensive and scientific essay about the New Hydrogen Economy by Chemical Engineer, Paul Martin..

Just published ....

https://cleanenergyrevolution.co/2023/03/12/hydrogen-to-replace-natural-gas-by-the-numbers/

Superb job Paul, as always .... Thank You Sir !!!

MJCronin
Sr. Process Engineer

 

[GregLocock]

H2 will indeed react with something in the atmosphere and become the biggest greenhouse gas by far. Water vapor.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[enginesrus]

I knew the escape to space deal, its the as its going there. So then we are going to send our water on this planet or what ever else they extract hydrogen from out to space, just like all the other stuff they have sent and would like to send. And thanks GregLocock.
How smart. The more massive the use of hydrogen is the more the chance of massive leaks and losses of it. Why not just stick to good ole clean mineral oil, that is plentiful. And stop the geoengineering then all will be nice.

 

[enginesrus]

"the only way freon ever got to the upper atmosphere is by aircraft, it used to be used as windshield deicer for high flying aircraft." ... I had not heard that before ... then why change SL refrigerant ? hype ?? (say it isn't so !!)

This was even reported on a TV show similar to, or 60 minutes, I'd say like 40 some years ago. It seems any thing about that now has been scrubbed, as it doesn't agree to well with the now! narrative.

 

[BrianPetersen]

That's because it's rubbish. The atmosphere is turbulent, and the normal process of turbulence and diffusion will carry even heavier-than-air gases upward. The mixture will be stratified, but the concentration of heavier-than-air gases higher up will still be non-zero.

 

[rb1957]

which particular piece of "rubbish" are you referring to ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[BrianPetersen]

I will let you figure that out while I unplug my EV and drive to one of my more distant customers today. I'll be on the road for a few hours, long enough that I'll have to plug in for a bit on the way while I have a coffee. Gotta go, the car is charged up and ready in the driveway.

 

[SkipVought]

"I'll have to plug in for a bit on the way while I have a coffee"

Now that's a plus in progress, like taking a break on a Conestoga crossing the prairie.

Skip,
[sub]
Just traded in my OLD subtlety...
for a NUance![/sub]

 

[dik]

Freon is a different problem... it breaks down the ozone, allowing more radiation to enter the earth's atmosphere and because of the reduction in the use of it, the ozone 'hole' has been repaired... It acts as a catalyst and deplete ozone without being affected itself... and continues to break down more ozone without being chemically altered.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[georgeverghese]

Energy conversion eff :
Solar panels: 20% max
Electrolysis : Believe this is currently approx 70%
H2 internal combustion engine (same as for current gasoline engines): 15%

Overall conversion : 0.2 x 0.7 x 0.15 = .02 = 2% roughly or 50:1

 

[enginesrus]

dik that is just it. The only way freon gets there is if it is put there on purpose. It can't fly there by itself.
So I now wonder how much of our H2o is gone because of electrolysis, that has been used for way over 100 plus years now? You know the H2 going to space.

 

[LittleInch]

Come on George.

Solar energy at arrival on earth is free.

ICE efficiency is more likely 30 to 35% surely.

So yes it's low overall but what's better?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BrianPetersen]

Start from electricity.
Charge/discharge efficiency of a good lithium (or sodium) battery is in the 90% range.
Powertrain efficiency of a good EV is in the 90% range.
About 80% of the electricity gets to propelling the vehicle.

Or ...
Electrolysis 70%
The process of compressing the hydrogen to 700 bar so that it can be stored in a practical volume eats up about a third of the chemical energy in the hydrogen and there's not a practical way to get this energy back at the point of use. Call it 70%
Fuel cell 70-ish-%
Powertrain efficiency same as the EV because it's the same stuff involved
So ... This route requires starting with 3 times as much electricity as if one went the EV route. 3 times as much solar collection area, 3 times as many wind turbines.

Or ...
Substitute 30% (optimistic) for powertrain efficiency if one were to use it in a combustion engine. In practical use in passenger vehicles, the average is quite a bit worse because they spend a lot of time operating "off design".
So .., This route requires starting with 10 times as much solar collection area, 10 times as many wind turbines as the battery EV route.

 

[MJCronin]

Here is a fun new study about Hydrogen usage in long-haul trucking:

https://thedriven.io/2023/04/03/hydrogen-for-long-distance-trucking-makes-no-sense-says-expert/

He says:

“The vehicles are at least double the cost of a battery electric vehicle and it costs three times more [in terms of energy] to run them than an electric vehicle.”

What do you think ?.... Is this guy wrong ???

MJCronin
Sr. Process Engineer

 

[SnTMan]

I can't see any way hydrogen makes any sense as a transportation fuel. You can't carry enough by volume to talk about.

“a scarce and precious resource” that should be quarantined for sectors like aviation or shipping

Aviation? Really? Dirigibles? LOL

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[dik]

It's still there, mostly from all the AC units, foam insulation plants and pressurised spray cans from down on the earth surface... they slowly make their way through the entire atomosphere due to molecular activity... they don't settle into the sewers and remain there, forever.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[georgeverghese]

@LI, I did that estimate merely to show that only 2% of solar radiation incident at PV solar panels gets converted to power output from an IC engine. Civilian transport IC engine average eff (from the US EPA btw) is pitifully low, 30-35% is from the newer gas turbines with ceramic coated air cooled blades running at very high temperatures. I havent heard of any improvements to IC engine energy eff. Smaller size industrial gas engines running at constant peak load would get to 25%, supercharging would get about 30% for the larger frames.
Its ironic that there is so much attention given to EVs' and H2 engines, all in the name of environmental protection, while there are millions of of tonnes of soft plastics leaching out into the oceans every year from landfills. Out here in Aus, soft plastics recycling / incineration has ground to a complete halt for some 6months now.

 

[BrianPetersen]

There's a tonne of problems to be solved, and just because someone else isn't addressing that other problem over there, shouldn't be an excuse to not address this problem right here.

Using hydrogen in a combustion engine is insanity, and I'm quite sure the economics will sort that out in due course.