Let's get started: Electrics, hydraulics or pneumatics, are
all means to transfer energy from one place to another. Electrics
are far more efficient and have less weight than either of the other
two. Hydraulics need heavy pumps, valves and lines to withstand the
high pressure and conversion efficiences are low.. Compressed
air needs a lot of ducting to get it to the right place. Wire does it
at a fraction of the cost and weight.
I fully agree.
The two batteries of the 787 have NOTHING to do with that, they are common for all airliners.
- APU start
- Elec Essential backup