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17-09-2021, 10:23 AM
#18931
Originally Posted by dobby41
Impossible today is old hat tomorrow.
Unfortunately we have pesky physics in the way! We've doubled the energy density of batteries within about a 10 year period, but even increasing the doubling to every 5 years it would take several lifetimes to reach comparable levels of storage with hydrocarbons, but that's if it's even physically possible.
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17-09-2021, 10:25 AM
#18932
Originally Posted by Zaphod
The density figures provided by Doug give you an idea of how much energy can be packed into a given space and explains why the battery pack used in a vehicle is so much larger than a fuel tank. Electric vehicles store much smaller amounts of energy on board, but are generally more efficient at using that stored energy. Basically, the calculations you've made above don't reflect all of the variables involved and might not be the best way to draw energy use comparisons between the two. It gets pretty complicated!
True - always wondered how birds can fly for many thousand of km's without rest when they have just this incredibly inefficient biofuel on board :
Albatrossrange.JPG
Godwits.JPG
To determine the range there are clearly other parameters to consider than just the energy density of the fuel storage container ...
Last edited by BlackPeter; 17-09-2021 at 10:28 AM.
----
"Prediction is very difficult, especially about the future" (Niels Bohr)
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17-09-2021, 10:35 AM
#18933
Originally Posted by causecelebre
AIR loves a good greenwash
Absolutely! I did the Air NZ survey last night and they are looking to get rid of plastic bag tags/membership for Koru/Frequent Flyers, for sustainability and digital technoology reasons. But at the same time looking at still being able to buy them. Whats the difference apart from saving Air NZ money??
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17-09-2021, 10:36 AM
#18934
Originally Posted by BlackPeter
True - always wondered how birds can fly for many thousand of km's without rest when they have just this incredibly inefficient biofuel on board :
Albatrossrange.JPG
Godwits.JPG
To determine the range there are clearly other parameters to consider than just the energy density of the fuel storage container ...
Isnt this why Air N Z has the Koru on its tail ?
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17-09-2021, 10:38 AM
#18935
so which bird can fly the furthest?
Capture.JPG
bearish engulfing on the weekly too!
the monthly is more ambiguous with the last few just spinning.
For clarity, nothing I say is advice....
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17-09-2021, 11:15 AM
#18936
Those godwits are amazing …this fella left Alaska for NZ but met a storm
From Miranda Trust:
Well the Godwit has had quite an adventure but ended up where he started, after flying for 57 hours and covering 4,200 kms, he is back on the Yukon delta, now he will have to refuel and hope he gets better weather on his next attempt
That’s averaging over 70kmh …cool
“ At the top of every bubble, everyone is convinced it's not yet a bubble.”
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17-09-2021, 12:45 PM
#18937
Member
Originally Posted by Zaphod
The density figures provided by Doug give you an idea of how much energy can be packed into a given space and explains why the battery pack used in a vehicle is so much larger than a fuel tank. Electric vehicles store much smaller amounts of energy on board, but are generally more efficient at using that stored energy. Basically, the calculations you've made above don't reflect all of the variables involved and might not be the best way to draw energy use comparisons between the two. It gets pretty complicated!
However, quite a few electric cars employ regenerative braking to harvest and re-store some of the energy back to the batteries (instead of burning it off at conventional brake pads) when braking and extend their range that way. That won't be an option with electric planes.....
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17-09-2021, 03:49 PM
#18938
Member
Originally Posted by Sideshow Bob
Absolutely! I did the Air NZ survey last night and they are looking to get rid of plastic bag tags/membership for Koru/Frequent Flyers, for sustainability and digital technoology reasons. But at the same time looking at still being able to buy them. Whats the difference apart from saving Air NZ money??
There's a big difference between "Zero emission's hydrogen powered air-craft", as touted by AIR, and "Zero emission's hydrogen". Remember we don't invest in green H2 in NZ, the vast majority is grey H2 production, the carbon waste coming from SMR using gas and, even worse, black H2 from coal gasification. Green H2 production won't be economic for another 25 years.
Minister Shaw is heading to COP26 knowing much serious NZ production of H2 is dirty, e.g. Glenbrook (for the next 14 years), when green H2 tech is being invested in overseas. Any green H2 produced here will likely be used to decarbonise indiustry here and for export. AIR will no doubt try to spin the use of grey H2 by using carbon capture or carbon offsets.
We should be using green H2 in industrial processes rather than pretending we can have a cheap aviation sector but without emissions. Industrial's aren't as sexy as aviation.
Last edited by causecelebre; 17-09-2021 at 04:16 PM.
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17-09-2021, 06:53 PM
#18939
Originally Posted by sideline
However, quite a few electric cars employ regenerative braking to harvest and re-store some of the energy back to the batteries (instead of burning it off at conventional brake pads) when braking and extend their range that way. That won't be an option with electric planes.....
You could potentially generate power by changing how reverse thrust for turbofan or turboprop jets is implemented, or for any type of descent maneuver. I still remain highly skeptical of large-scale electrification of aircraft at this point however.
Last edited by Zaphod; 17-09-2021 at 07:24 PM.
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17-09-2021, 07:51 PM
#18940
My Li-Ion battery electric mower is getting a bit gutless after only 3 years.
Cant see this current (lol) technolgy giving the longevity neccesary to make the investment wortwhile.
Its not particularly relevant i guess but this first experience with replacing an ICE with electric battery isnt impressing me
i couldve put this in the electric car thread
For clarity, nothing I say is advice....
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