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Airbus: Hydrogen Powered Airliners by 2035

Old 04-15-2021, 01:03 AM
  #21  
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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.
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Old 04-15-2021, 06:42 AM
  #22  
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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.
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Old 04-15-2021, 07:49 AM
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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.
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Old 04-15-2021, 11:03 AM
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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.
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Old 04-15-2021, 03:33 PM
  #25  
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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.
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