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A comment on The Third Phase of Clean Energy Will Be Most Disruptive Yet. Parent comment

Re:The Third Phase of Clean Energy Will Be Most Disruptive Yet by tachyonbeam on Wednesday April 03, 2019 @01:03PM (#19565036)
Could we power airplanes with ethanol? I've heard that we couldn't realistically grown enough corn/canes to produce ethanol for all cars, but if cars are electric, could we potentially produce enough ethanol for airplanes?

If we can't make enough ethanol for all air travel, I'm still optimistic. It's likely that battery densities will become good enough for us to have electrically powered regional jets within the next decade. Then only long flights would need liquid fuels. As a last option, we could also switch to high-speed trains for continental travel.

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Re:The Third Phase of Clean Energy Will Be Most Disruptive Yet by i_am_proteus on Wednesday April 03, 2019 @01:17PM (#19565158)
Piston-engined aircraft, which are basically just light general aviation aircraft, can and have used ethanol.

Most commercial aircraft use jet engines. Other biofuels that are chemically closer to kerosene can be used in most existing jet engines in blends; use of 100% biofuels for hasn't been extensively tested-- but it has been tested![0] This is also the highest-hanging fruit and I wouldn't worry about it in 2019.

[0]https://www.navy.mil/submit/display.asp?story_id=96702

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Re:The Third Phase of Clean Energy Will Be Most Disruptive Yet by ams6110 on Wednesday April 03, 2019 @02:00PM (#19565582)
Turbine engines in theory can run on almost any flammable liquid. However in practice they would need substantial re-engineering. Also ethanol is less energy-dense than kerosene/jet fuel.
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Re:The Third Phase of Clean Energy Will Be Most Disruptive Yet by sokoloff on Wednesday April 03, 2019 @10:46PM (#19568928)
Have high-power turbocharged piston engines been run on ethanol in service? I’m not aware of any. GA piston fleet has the common property where 20% of the fleet burns 70+% of the fuel as they are working airplanes. (Think CapeAir and similar in passenger service.) Those highly stressed turbocharged engines have lower detonation margins, currently requiring tetraethyl lead additive to meet worst case detonation margins.
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Re:The Third Phase of Clean Energy Will Be Most Disruptive Yet by jhayward on Wednesday April 03, 2019 @02:32PM (#19565931)
The US DOD has a project which qualifies what is essentially biodiesel (bio-derived JP8) for use in jet aircraft.

There's not a lot of work to do, just the details of making a mil-spec standard and then doing the testing in each engine type. In other words, everyday blocking and tackling not scientific breakthroughs.

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