Connect and get the inside scoop on Airline Companies

Welcome to Airline Pilot Forums - Connect and get the inside scoop on Airline Companies

If this is your first visit, be sure to check out the FAQ. Join our community today and start interacting with existing members. Registration is fast, simple and absolutely free.


User Tag List

Post Reply
 
Thread Tools Search this Thread
Old 04-15-2021, 01:03 AM   #21  
Gets Weekends Off
 
HIFLYR's Avatar
 
Joined APC: Sep 2007
Position: 777 Captain in Training
Posts: 1,232
Default

Quote:
Originally Posted by rower View Post
"What is the Disadvantage of Hydrogen Fuel Cells?

Hydrogen Extraction
Despite being the most abundant element in the Universe, hydrogen does not exist on its own so needs to be extracted from water via electrolysis or separated from carbon fossil fuels. Both of these processes require a significant amount of energy to achieve. This energy can be more than that gained from the hydrogen itself as well as being expensive. In addition, this extraction typically requires the use of fossil fuels, which undermines the green credentials of hydrogen."

Source: https://www.twi-global.com/technical...gen-fuel-cells

Those who claim that hydrogen is the future of fuels for: "trains, planes and automobiles" do not know physics and chemistry.
But battery power will be, right. How you going to run a bulldozer, combine, ship, transcontinental aircraft, etc ? If you say they can overcome the engineering obstacles, then they can just as likely overcome the hydrogen engineering obstacles. You could use the new safer nuclear options to get hydrogen. Batteries require destroying the environment for heavy minerals for their construction and environmental problems for their disposal.
HIFLYR is offline  
Old 04-15-2021, 06:42 AM   #22  
Prime Minister/Moderator
 
rickair7777's Avatar
 
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
Posts: 29,176
Default

Quote:
Originally Posted by HIFLYR View Post
But battery power will be, right. How you going to run a bulldozer, combine, ship, transcontinental aircraft, etc ? If you say they can overcome the engineering obstacles, then they can just as likely overcome the hydrogen engineering obstacles. You could use the new safer nuclear options to get hydrogen. Batteries require destroying the environment for heavy minerals for their construction and environmental problems for their disposal.
Fuel cells are better than batteries *if* you have the infrastructure to deliver the fuel. We're using batteries right now because we already have the infrastructure (the grid). The grid can become greener over time, but as you mentioned I think that needs a lot of (modern tech) nuclear to get where they claim they want to be.
rickair7777 is offline  
Old 04-15-2021, 07:49 AM   #23  
New Hire
 
Joined APC: Apr 2021
Posts: 2
Default

You can not use nuclear power to extract hydrogen from water or fossil fuels because all methods we know today are inefficient.
You have to generate 3 kWh of electricity in a nuclear plant to obtain hydrogen that, as fuel for a vehicle, will produce just 1 kWh of mechanical work.
rower is offline  
Old 04-15-2021, 11:03 AM   #24  
Prime Minister/Moderator
 
rickair7777's Avatar
 
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
Posts: 29,176
Default

Quote:
Originally Posted by rower View Post
You can not use nuclear power to extract hydrogen from water or fossil fuels because all methods we know today are inefficient.
You have to generate 3 kWh of electricity in a nuclear plant to obtain hydrogen that, as fuel for a vehicle, will produce just 1 kWh of mechanical work.
Sure you can. It doesn't have to be efficient as long as it's green. More nuclear doesn't increase carbon (other than the inevitable carbon overhead associated with any industry and the people who work there).

Also your math assumes that the H2 is cooled to a cryogenic state which requires additional energy. That's correct for airplanes, but worth noting that if you wanted to replace natural gas with H2, you could get about 70% conversion efficiency out of electrolysis as long as the H2 gas produced is simply pumped directly into a pipeline, vice cooled or compressed for vehicle storage tanks. My SWAG would be that we'll just go all-electric for residential and light industry just due to the potential hassle (and increased danger) of plumbing H2 gas into everybody's homes. H2 gas might be useful as a surge accumulator though, since generating capacity could make H2 all night which would then cover the normal morning surge when people get up, turn on the heater and take hot showers. Although solar naturally tends to balance out that peak cycle if you have enough of it.

The real obstacle for H2 in planes is energy density, ie storage takes up too much volume on the plane which means more structure, which means more weight, which requires more fuel, etc, etc. might be able to mitigate with large-volume designs, ie BWB.
rickair7777 is offline  
Old 04-15-2021, 03:33 PM   #25  
Gets Mon-Sun Off
 
TransWorld's Avatar
 
Joined APC: Aug 2016
Position: Up Front
Posts: 3,226
Default

Quote:
Originally Posted by rower View Post
You can not use nuclear power to extract hydrogen from water or fossil fuels because all methods we know today are inefficient.
You have to generate 3 kWh of electricity in a nuclear plant to obtain hydrogen that, as fuel for a vehicle, will produce just 1 kWh of mechanical work.
And most nuclear power plants make about 3 kWh of thermal heat which generates 1 kWh of electricity. So, about 1 kWh of mechanical work for every 9kWh of power from the nuclear core.
TransWorld is offline  
 
 
 

 
Post Reply
 



Thread Tools Search this Thread
Search this Thread:

Advanced Search


Related Topics
Thread Thread Starter Forum Replies Last Post
Fedex and UPS A380 Freighter Flea Bite Cargo 34 07-12-2006 04:21 PM
Letter to NTSB regarding AA 587 ADIRU Major 13 06-07-2006 12:48 PM
Airbus admits A350 flopped, to spend $10 billion on new plane Gordon C Major 46 05-15-2006 10:48 PM
Boeing gains major ground against Airbus captain_drew Hangar Talk 0 12-30-2005 07:03 PM
Singapore Air head furious at Airbus Sir James Hangar Talk 0 08-07-2005 11:40 AM


All times are GMT -8. The time now is 06:25 AM.