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First all-electric seaplane takes flight in B.C.

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Re: First all-electric seaplane takes flight in B.C.

#141

Post by seanmcdirmid »

mrpopo wrote: post #123
eloff wrote: post #96

Earlier quoted context omitted.

We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could…

> All we need to do is make it carbon neutral and our existing aviation tech won't even need to change. Except making it carbon neutral will require enormous amounts of energy, shift the price up, and make aviation available only to the richest among us. Aviation industry may keep existing, but will need to scale down.

Well, if we ever figure out fusion, we could get the enormous amount of energy part.

Re: First all-electric seaplane takes flight in B.C.

#142

Post by WalterBright »

SEJeff wrote: post #110
eloff wrote: post #96

Earlier quoted context omitted.

We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could…

Methane can be created via carbon capture entirely. It is in the SpaceX TODO list to create a factory to literally create metholox (methane + liquid oxygen is what they use as fuel for the new Starship / Superheavy rockets they want to use to go to mars) via carbon capture. Elon has already discussed this before. The end goal that the rocket launch is carbon neutral when you are using carbon already captured from the…

The whole "carbon neutral" think is a crock. Coal is, after all, just dead trees, so coal plants run on "biofuel" and are "carbon neutral".

Re: First all-electric seaplane takes flight in B.C.

#143

Post by WalterBright »

jjoonathan wrote: post #103
eloff wrote: post #96

Earlier quoted context omitted.

We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could…

Or biofuel. Plants are good at capturing atmospheric CO2 and the resulting biomass can be turned into fuel using well established technology. If it's nearly suitable for cars I suspect it's even more nearly suitable for aviation on account of the lower volumes and higher margins.

> Plants are good at capturing atmospheric CO2 and the resulting biomass can be turned into fuel using well established technology.

I.e. burning coal.

Re: First all-electric seaplane takes flight in B.C.

#144

Post by WalterBright »

deepspace wrote: post #47
semi-extrinsic wrote: post #27

You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…

> This thing is 560 kW and gets a range of 86 nmi Not even that. I believe an 86 nmi range is what they are hoping to achieve by 2025. Current range is a fraction of that. The technology demonstrator has a theoretical flight time of 15 minutes and no ability to carry passengers because all the room/weight is taken up by batteries.

"Kelly was now so desperate to save weight that he upped the ante to one hundred and fifty bucks to anyone who could save him a measly ten pounds. I suggested we inflate the Blackbird's tires with helium and give each pilot a preflight enema. Kelly tried the helium idea, but helium bled right through the tires. The enema idea he left to me to try to promote among the pilots."

   -- "Skunk Works" by Ben Rich

Re: First all-electric seaplane takes flight in B.C.

#145

Post by umeshunni »

hnick wrote: post #128
eloff wrote: post #96

Earlier quoted context omitted.

We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could…

I don't really know where else to ask, so I'll ask here. Another topic of research is very rapid sub-orbital passenger flight. Are there any numbers on proposed fuel efficiency for that? I'd expect you gain a lot by removing hours and hours of wind resistance, but getting up to speed and out of the atmosphere probably (gut feel) uses more.

No numbers, but you might have seen the SpaceX proposal / video here: https://www.youtube.com/watch?v=zqE-ultsWt0

Re: First all-electric seaplane takes flight in B.C.

#146

Post by WalterBright »

avmich wrote: post #60
darksaints wrote: post #53

Earlier quoted context omitted.

Fuel cells are a possibility. There is some pretty high power densities (2.5kw/kg for SOFCs, 10kw/kg for less efficient PEMs). Electric motors are now reaching 15kw/kg. For comparison, a GE90 is about 10kw/kg, and older turbofans down to 2kw/kg. Running on liquid hydrogen presents some problems that are definitely solvable, but SOFCs can run on pretty much any hydrocarbon fuels at extremely high efficiencies (50-60%,…

There reportedly is an additional threat to the climate coming from inversion traces (modifies enough of Earth albedo?), so if we're delivering water to high altitudes, it's still not good. Electrical motors would solve this; if we'd be able to avoid dispersing water from fuel cells up high, that could work. LH2 has storage - and safety - issues still not solved. Toyota Mirai approaches it from a different angle, wit…

Burning kerosene also delivers water to high altitudes - the result is contrails.

Re: First all-electric seaplane takes flight in B.C.

#147

Post by ben_w »

WalterBright wrote: post #142
SEJeff wrote: post #110

Earlier quoted context omitted.

Methane can be created via carbon capture entirely. It is in the SpaceX TODO list to create a factory to literally create metholox (methane + liquid oxygen is what they use as fuel for the new Starship / Superheavy rockets they want to use to go to mars) via carbon capture. Elon has already discussed this before. The end goal that the rocket launch is carbon neutral when you are using carbon already captured from the…

The whole "carbon neutral" think is a crock. Coal is, after all, just dead trees, so coal plants run on "biofuel" and are "carbon neutral".

Technically correct, but about as unhelpful as saying “solar isn’t renewable because the sun will eventually go out”.

Our biology and our biosphere are not adapted to the atmospheric CO2 levels we would have if we burned all the fossil fuels.

Re: First all-electric seaplane takes flight in B.C.

#148

Post by davedx »

hnick wrote: post #128
eloff wrote: post #96

Earlier quoted context omitted.

We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could…

I don't really know where else to ask, so I'll ask here. Another topic of research is very rapid sub-orbital passenger flight. Are there any numbers on proposed fuel efficiency for that? I'd expect you gain a lot by removing hours and hours of wind resistance, but getting up to speed and out of the atmosphere probably (gut feel) uses more.

I also haven't seen numbers, but I imagine the energy usage even to reach sub-orbital altitude would be pretty huge compared to a jet plane takeoff -> cruising altitude. Sub-orbital means you also have to bring your own oxygen too (rocket vs jet engine), which can approximately double your fuel mass...

Re: First all-electric seaplane takes flight in B.C.

#149

Post by m-i-l »

WalterBright wrote: post #142
SEJeff wrote: post #110

Earlier quoted context omitted.

Methane can be created via carbon capture entirely. It is in the SpaceX TODO list to create a factory to literally create metholox (methane + liquid oxygen is what they use as fuel for the new Starship / Superheavy rockets they want to use to go to mars) via carbon capture. Elon has already discussed this before. The end goal that the rocket launch is carbon neutral when you are using carbon already captured from the…

The whole "carbon neutral" think is a crock. Coal is, after all, just dead trees, so coal plants run on "biofuel" and are "carbon neutral".

> The whole "carbon neutral" think is a crock. Coal is, after all, just dead trees, so coal plants run on "biofuel" and are "carbon neutral".

The difference is in the timeframes for capture and replacement - with coal it is millions of years, and with wood it is years. That means burning coal releases carbon which was trapped millions of years ago, and it would take millions of years to trap equivalent amounts of carbon with the formation of new replacement coal deposits. Burning wood on the other hand releases carbon that has been trapped within our lifetime, and it is easy to replace with new trees grown in our lifetime. Bear in mind that if we reverse millions of years of carbon capture we would revert the atmosphere to what it was like millions of years ago, and time travellers visiting that era are likely to need breathing equipment.

Re: First all-electric seaplane takes flight in B.C.

#150

Post by philhippus »

WalterBright wrote: post #143
jjoonathan wrote: post #103

Earlier quoted context omitted.

Or biofuel. Plants are good at capturing atmospheric CO2 and the resulting biomass can be turned into fuel using well established technology. If it's nearly suitable for cars I suspect it's even more nearly suitable for aviation on account of the lower volumes and higher margins.

> Plants are good at capturing atmospheric CO2 and the resulting biomass can be turned into fuel using well established technology. I.e. burning coal.

Yes, but it takes 100's of thousands of years for the planet to form fossil fuels such as coal. We can't wait that long.
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