That is a very good and often overlooked point. So in average on a flight one has to calculate maybe with 60% weight of kerosene, while the battery keeps 100% of its weight during the entire flight.

It gets worse with lithium air batteries that actually gain weight as they discharge because of the formation of solid oxides from the air. Argonne are reporting 1200Wh/kg in the lab though so still worth it.

Dumping batteries might be a thing? After all it is an emergency!

With parachutes, and you can reuse them.

You can also do this on regular flights just to save weight. It's SpaceX style reusability but on a commercial aviation scale.

Electric engines may be much more reliable than kerosene engines.

This is more about day to day operations than emergencies. For an electric plane, your MTOW (max takeoff weight) is equal to your MLW (max landing weight). An ICE plane can take off with "bonus" fuel that it can't land with for structural reasons, while an electric plane can't.

I would hope so, considering this is what it looks like inside. https://en.wikipedia.org/wiki/Rolls-Royce_Trent_1000#/media/...

But. Turbine engine is actually very reliable and doesn't need overhaul for 20,000 flight hours.

The problem here is single-engine planes losing engine on takeoff. Would be almost non-issue with electrics.

Electric planes could recharge using solar or wind. As efficiency increases with these technologies, it would mean planes wouldn't require carrying the same watt-for-watt energy as fuel.

> Electric planes could recharge using solar or wind. As efficiency increases with these technologies, it would mean planes wouldn't require carrying the same watt-for-watt energy as fuel.

Those are pipe dreams :-)))

Solar recharging for electric cars is not realistic, let alone for electric planes.

Wind charger... maybe there's something there, but the fact that nobody has tried it probably means it's not good enough.

https://www.arenaev.com/why_solar_panels_on_cars_are_beyond_...

> So under optimal conditions the Hyundai solar roof would yield 280kWh *yearly*. In London you'd get 164kWh.

Planes have a much larger surface area to carry solar panels, and they fly above clouds, so have clearer access to sunlight than cars do.

Wind charging is more of a pipe dream, but there's no reason a plane couldn't glide for a period of time to get some energy back, similar to regenerative breaking.

There have been experiments in both areas, and while it's certainly unfeasible today for any large aircraft, the technology and efficiency will only improve. It would be wrong to discard these as an impossibility.

The concepts of potential energy and kinetic energy make the "wind charging" idea ... difficult.

The extra weight and structural challenges imposed by solar panels on aircraft don't seem worth it. The math on (174 sqft) * ideal theoretical power (250 W /m2) yields an optimistic ideal 4000 Watts. A conservative 75% power usage of a 172 engine is around 100kW. 4% under ideal circumstances.

> Planes have a much larger surface area to carry solar panels, and they fly above clouds, so have clearer access to sunlight than cars do.

And the energy they require for flying is an order of magnitude than that required to drive stuff on the ground.

> And the energy they require for flying is an order of magnitude than that required to drive stuff on the ground.

Take off requires a lot of resources, but maintaining altitude and speed are likely minimal additional energy.

Recharging a small plane with solar power would either take ages or hectares. Pick your poison.

Recharging multiple airliners will take a nuclear reactor at the airport.

Recharging would take a lot of energy but it's not unthinkable to have 1-3 GW supplied to an airport (which is what a reactor would likely supply), large metropolitan areas and large industrial factories already get to similar amounts. It's a couple of transmission lines and most large airports are close to population centers anyway.

The challenge would be getting the right amount at the right time, like now with quick charging. Like there, you'd probably have buffer storage at the airport so that it consumes electricity when available (e.g. during the day from solar) and dispenses it to aircrafts when needed. Luckily, most airports in the world have nearly all take offs and landings during the day, so there's a big overlap. Dubai would be an example where likely all would come from solar but a lot is needed over night (if we ever get electric long-haul flights).

So overall I don't think that this would be the limiting factor. But I guess larger airliners are more likely to run on synthetic fuels than electricity for a long time. And I guess that's fine, we have a lot of areas where cheap and/or dense batteries can help us much more in the short term (grid storage, cars, trucks).

This is true. It’s a big engineering project, but, guess what, airports are very big engineering projects.

It's way cheaper and more efficient for electricity consumers to purchase power from the grid, and for the grid to figure out the most optimal way to produce and deliver the power.

Solar and wind are in many areas a) only available during certain hours b) expensive.

To ensure you have a stable power cost, and stable power availability, you as a large consumer (In the EU) make PPA agreements with power producers for specific KW rates, for specific KWh amounts, for specific times. These are complicated agreements.

A few panels on some warehouses and hangers close to an airport could keep the lights and the A/C on in the terminal, but that's about it. No one is putting up wind turbines anywhere close to an airport.