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There might not be a need to equal the energy density of jet fuel in a battery. If the efficiency of the engine and propulsion improve significantly compared to
by PietdeVries 11y ago
There might not be a need to equal the energy density of jet fuel in a battery. If the efficiency of the engine and propulsion improve significantly compared to fuel jets, an electrical system might not need that much energy after all.
See the hybrid car: the efficiency of a regular engine (VW Diesel not taken into account ;-) is relatively low. If an electrical engine can be twice as efficient, you only need half the energy...
- ohazi 11y agoWait, what? A good electric motor is already ~90% efficient. How are you going to double that?
- kruczek 11y agoBy reducing wasted energy by half, thereby increasing efficiency to ~95%.
- mlonkibjuyhv 11y agoBut you're still only increasing useful energy by a few percent. Surely that's the interesting quantity here.
- mhandley 11y agoThe electric motor is around 90% efficient, but the thermal efficiency of a jet engine is (if I recall correctly) only around 30%. So the batteries only need to contain 1/3 of the energy of the jet fuel. Batteries are still a long way off from this, but that factor of 3x makes it somewhat nearer than it would otherwise be.
- jkot 11y agoAnd what about dead weight of battery after its empty?
- deleted 11y ago[deleted]
- doctorstupid 11y agoBut jets combine the energy of air and fuel, whilst electric motors are solely powered by batteries.