Why battery-powered aircraft will never have significant range

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emotodude

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And once you've got this "renewably-produced" hydrogen (Ha! Look at the >lifecycle< environmental impact of wind and solar), we'll need to compress, transport and store it. Not easy. And you'd best start with clean water--something that isn't in universally abundant supply--good for drinking, producing food, etc.
Most hydrogen produced today is made using natural gas as a base stock--that's a LOT less expensive than electrolysis, and environmentally more sound (considering that electricity--from any source--would be best used to displace electricity produced by dirtier/more expensive sources.)
For fuel cells, expect that the first practical ones in widespread use will use fuels that are liquid at/near typical ambient temperatures--just like our present hydrocarbon transportation fuels. It's an incredibly compact and convenient way to transport energy.
On-site generation largely resolves the transportation issues. Your other points are valid, but surmountable. Methanol or Ammonia Reformers and Fuel Cells will be technologies to watch...
 

emotodude

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The quickest path to carbon neutral is to produce hydrogen with the lowest carbon and scalable energy source, which is nuclear. Then extract carbon dioxide from air and use it to make a stable hydrocarbon like propane.
Large experimental carbon dioxide extractors from air are being built currently.
Agreed! Actually not opposed to this approach. Some applications, like long range flight, will require hydrocarbon based fuels for at least a couple decades...

I feel like everyone just gets so entrenched in a "one size fits all" energy solution. Lately I've been saying "battery when you can, H2 when you must". This could be extended to hydrocarbons as well. Energy storage preference should be something like Battery>H2>Hydrocarbons. Power generation should be something like Renewables>Nuclear>Coal/Gas
 

Billrsv4

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And once you've got this "renewably-produced" hydrogen (Ha! Look at the >lifecycle< environmental impact of wind and solar), we'll need to compress, transport and store it. Not easy. And you'd best start with clean water--something that isn't in universally abundant supply--good for drinking, producing food, etc.
Most hydrogen produced today is made using natural gas as a base stock--that's a LOT less expensive than electrolysis, and environmentally more sound (considering that electricity--from any source--would be best used to displace electricity produced by dirtier/more expensive sources.)
For fuel cells, expect that the first practical ones in widespread use will use fuels that are liquid at/near typical ambient temperatures--just like our present hydrocarbon transportation fuels. It's an incredibly compact and convenient way to transport energy.
One thing ignored in this arguement is that a properly designed PEM fuel cell can produce H2 at up to 3000 psi when used as an electrolizer. Power from renewable sources could even be used to run the cell.
 

Speedboat100

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Reichelt flew with just 750 watts of power.

I think Reichelt was in the class of his own....flying with 750 watts is pure art ( like enclosed pic ).
I figure that when you have aspect ratio and L/D about 3 x better than Cessna 172 and also the loaded ratio at 4 like in Rutans Voyager....you will no longer see any problem with the electric AC range ?

Who is with me in this ?

koller-elephante-baloon.jpg
 

BBerson

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Solar only works about 4 hours of a 24 hour day cycle. Solar should not be called "renewable" at all. Solar is and should be classed as "unreliable" energy. It requires a base load "reliable" energy source such as nuclear, natural gas or biomass (trees). Solar is just an inconvenience to the grid operators that drives up the cost and will never get to carbon neutral. Getting near into political now... so get some videos of Alex Epstein or his book Moral Case For Fossil Fuels for more details.
 
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Vigilant1

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One thing ignored in this arguement is that a properly designed PEM fuel cell can produce H2 at up to 3000 psi when used as an electrolizer. Power from renewable sources could even be used to run the cell.
-It is no more efficient than electrolysis, so no energy savings.
- I suppose there could be capital savings in equipment if we use equipment on board the aircraft ( a reversible PEM fuel cell/hydrolizer) to make H2 from ground power. Just be prepared for a long wait to fill up.

And we are still left with a major problem of pressurized H2: poor volumetric energy density.
H2 at 3000 psi: 6,500 btu per gallon
Gasoline: approx 115,000 btu per gallon.

So, about 18 gallons of high pressure hydrogen to equal 1 gal of gasoline. Even with very efficient conversion of that H2 to mechanical energy, our fuel tank would still need to be huge.

And then we'd need to factor in the weight of the tank needed to contain that 3000 psi hydrogen.

Hydrogen is not the answer.
 

Speedboat100

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Solar only works about 4 hours of a 24 hour day cycle. Solar should not be called "renewable" at all. Solar is and should be classed as "unreliable" energy. It requires a base load "reliable" energy source such as nuclear, natural gas or biomass (trees). Solar is just an inconvenience to the grid operators that drives up the cost and will never get to carbon neutral. Getting a bit into political now... so get some videos of Alex Epstein or his book Moral Case For Fossil Fuels for more details.

Solar could be a range extender, but I would not rely solely on it either....albeit sun does shine everyday above the clouds...not so much at the night time.
 

Pale Bear

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-It is no more efficient than electrolysis, so no energy savings.
- I suppose there could be capital savings in equipment if we use equipment on board the aircraft ( a reversible PEM fuel cell/hydrolizer) to make H2 from ground power. Just be prepared for a long wait to fill up.

And we are still left with a major problem of pressurized H2: poor volumetric energy density.
H2 at 3000 psi: 6,500 btu per gallon
Gasoline: approx 115,000 btu per gallon.

So, about 18 gallons of high pressure hydrogen to equal 1 gal of gasoline. Even with very efficient conversion of that H2 to mechanical energy, our fuel tank would still need to be huge.

And then we'd need to factor in the weight of the tank needed to contain that 3000 psi hydrogen.

Hydrogen is not the answer.
18 to 1 ratio .. no, that's not great. Dang, .. there goes my theory of having H2 plants built around all the wind turbines, here.
 

Toobuilder

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Un-informed hookum. Please google "cheapest source of energy" and educate yourself.

Aside from the fact that I'm not going to take interest in electric airplanes until they can deliver me, my wife and 100 pounds of stuff 1000 miles at 200 knots, and then refuel within 15 minutes, you have really jumped the shark by citing Wikipedia as a "truth source". If wind was so incredibly cheap, then there would be no need to subsidize so deeply. I live in a significant area of wind turbine activity, and after seeing these things crop up like weeds and ruin my local environment for the past 20 years, I can say I'd rather have a nuke plant next door. I live downwind from several thousand of these things and my power bill has only gone up.

Im all for the most efficient delivery of power, but it has to be based on engineering units - not political spin.
 

emotodude

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Aside from the fact that I'm not going to take interest in electric airplanes until they can deliver me, my wife and 100 pounds of stuff 1000 miles at 200 knots, and then refuel within 15 minutes, you have really jumped the shark by citing Wikipedia as a "truth source". If wind was so incredibly cheap, then there would be no need to subsidize so deeply. I live in a significant area of wind turbine activity, and after seeing these things crop up like weeds and ruin my local environment for the past 20 years, I can say I'd rather have a nuke plant next door. I live downwind from several thousand of these things and my power bill has only gone up.

Im all for the most efficient delivery of power, but it has to be based on engineering units - not political spin.
There are many cited studies in that wikipedia entry and elsewhere on the interwebs that substantiate my claims of energy productions costs. You are free to read and research as much as you want, or not... It doesn't change the facts. Feel free to post credible studies showing otherwise! I'm always willing to learn. I am also a proponent of Nuclear power where it makes sense. I am no energy bigot, as I said earlier there is no "one size fits all" solution.
 

Toobuilder

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Studies on the internet do not replace market forces. If "wind" power was a significantly lower cost of delivery than other energy sources, the the suppliers of the energy product would run (not walk) to provide that product. They would not need to be dragged into the market by government incentive - the ability to provide a product with higher profit margins would be all the incentive needed.

That's the beauty of capitalism - it is the "truth" behind human nature. If wind or solar was "cheap", it would be the primary energy source for the planet. But it's not.
 

emotodude

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Solar only works about 4 hours of a 24 hour day cycle. Solar should not be called "renewable" at all. Solar is and should be classed as "unreliable" energy. It requires a base load "reliable" energy source such as nuclear, natural gas or biomass (trees). Solar is just an inconvenience to the grid operators that drives up the cost and will never get to carbon neutral. Getting near into political now... so get some videos of Alex Epstein or his book Moral Case For Fossil Fuels for more details.
Alex Epstein's book is hardly considered authoritative or credible by many and heavily leans on denying climate change...

Here's a very well sourced review of his book and arguments

I actually worked in the energy industry and your statements about inconvenience are just wrong. Solar production is quite predictable and generally mirrors peak consumption rates reasonably well. And it is far cheaper than fossil sources.

Variable H2 production rates and "smart grid" technology will allow us to load level and store energy on unprecedented scales. I don't understand the resistance to change. 2 decades ago this this same sort of thinking would deny the viability of battery electric cars. Nowadays all major car manufacturers are planning on going to full electric over the next decade or two. The same will happen with aviation, just on a longer time scale.
 
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pictsidhe

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Plenty of unsubsidised wind farns are getting built in europe. Whether that makes financial sense is dependent on many things. Wind speed being a huge factor
 

Vigilant1

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Plenty of unsubsidised wind farns are getting built in europe. Whether that makes financial sense is dependent on many things. Wind speed being a huge factor
European renewable energy mandates are a very real form of subsidy to these schemes. They wouldn't be built without them. There are lots of ways to put a thumb on the scale . . .
 

emotodude

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European renewable energy mandates are a very real form of subsidy to these schemes. They wouldn't be built without them. There are lots of ways to put a thumb on the scale . . .
"they wouldn't be built without them" Sources to back up your claims?
 

BBerson

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Solar production is quite predictable and generally mirrors peak consumption rates reasonably well.
Not here. Peak solar is July and the Bonneville electric has too much excess power and the industrial energy rate can go negative to avoid damage releasing too much water at once.
We need peak power in January. Yet the state has a $.53 per KWH Photovoltaic subsidy. It isn't competive without subsidy.
 

emotodude

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Not here. Peak solar is July and the Bonneville electric has too much excess power and the industrial energy rate can go negative to avoid damage releasing too much water at once.
We need power peak power in January. The state has a $.53 per KWH Photovoltaic subsidy. It isn't competive without subsidy.
Totally agree solar is not the correct solution Everywhere, All the time. Nor is Wind or any other solution. Nuclear baseload with renewable "as makes sense" is probably the best way forward. H2 and smart grid will expand the viability of renewables over time.
 

BBerson

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Nuclear baseload with renewable "as makes sense" is probably the best way forward. H2 and smart grid will expand the viability of renewables over time.
The "renewable" industry is blocking advanced nuclear with over regulation.
 

henryk

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Nuclear baseload with renewable "as makes sense" is probably the best way forward.
=?

-in one qubic meter of cold atmospheric AIR is accumulated circa 150 kJ (kilo Jouul)
KINETIC energy !!! =NO need in nuclear,focile sources etc. ...

E=0.5 m * V^2 = 0.5* 1.3 [kg] * 500 ^2 [m^2/s^2 ] =150000 J

=look at tornado kinematic.
 

Vigilant1

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"they wouldn't be built without them" Sources to back up your claims?
It isn't polite to argue about religion, so I won't be going down this rabbit hole with you. The renewable energy mandates clearly drive up the cost of energy (this is not in dispute) and serve as a transfer payment to producers of renewable power.
More here with a simulation of the mechanics.
The intermittent nature of wind and solar power imposes higher stress on the grid and as their share of total capacity increases, the marginal value of each added watt they contribute decreases. Concomitantly, the value of dependable baseline power capacity increases.
 
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