Originally Posted by
meleagertoo
Well, you gonna be waiting an awful long time before anyone comes up with an aeroplane that can manage any sort of credibly useful performance to compare with conventionally fueled ones.
Even longer for airline size and performance, barring a revolutionary and to-date unanticipated breakthrough in battery technology or realisation of fuel cells.
It's a simple matter of energy density - how much energy can be stored in the space available. Currently batteries lag two orders of magnitude behind fossil fuels in this.
LiIon batteries currently stand in the range of .4 to .8 MJ/Kg. Jet A1 is 48. That's one hundred times more.
Certainly some necessarily small future aerodynamic and weight effciencies will narrow the gap slightly (small because those sciences are pretty much at peak already)
Batteries got some catching up to do!
True to some degree. However, only around 45% at best of the energy stored in the Jet A1 will eventually be translated into forward force. Electric motors on the other hand are at an efficiency of +95% of using the energy in the battery. Of course that does not close the gap yet in aviation, so yes, battery technology has ways to go.
On the car side however, it is already very close. As those engines are rarely if ever used at their optimal point of specific fuel usage, they have an average efficiency of around 17% for gasoline cars and around 20% for diesel ones. On the other hand, a 100kWh battery, the largest size currently available for cars, has only the energy that around 11 litre of gasoline have. So yes, in that application electrification is much more sensible currently.