How far are we from electric planes?

Robert asks how high and how fast could electric aircraft fly, and how far away are we from actually having an electric aeroplane as reality? Chris Smith put this to Tim Revell from New Scientist...

Tim - I'd say we’re still quite a long way from the reality of flying around rather in sort of jumbo jets like they are but electric versions. That's not happening any time soon. And the problem is with electric aircraft is it just takes so much energy, to fly anything, but with an electric aircraft you need a lot of batteries and batteries are really really heavy. The heavier something is the more energy it needs so the more batteries you need. And if you've ever flown a drone you will have seen this.

You get these tiny little drones that get into the air really really quickly and a lot of fun to fly around. And eight minutes later your battery is flat. You can get some slightly bigger drones but even the big ones are there much much heavier. But even those can only fly for 30 minutes or an hour. We're talking about very short periods of time.

But that's not to say we don’t have any electric planes. There are some that have been successful and perhaps the most famous one is called Solar Impulse 2. This one had solar panels on it, was created by a Swiss team, and in 2015 it circumnavigated the globe. But the problem was it had to keep stopping and the whole journey took 16 months and it only had room for one person.

That's sort of the height as it were of electric planes at the moment. And so to answer the original question of “how high and how fast”... Solar Impulse 2 travelled at about 70 kilometers an hour, which just sort of 43 miles per hour, and was about 12000 meters in the air or about 40000 feet. In terms of height that's about the same height as a jumbo jet. We're talking similar sort of distance into the air.
But in terms of speed, a jumbo jet will easily do 500 miles an hour. It was doing 43 miles an hour. So we're a long way off at that.

But people would love to have electric aeroplanes because air transport is an absolutely terrible polluter of the air and it's also adding to our greenhouse gas emissions so it's also bad for the environment in many many different ways. The problem is we just don’t have good enough technology yet to make flying aircraft that would be sustainable and do the job that aircraft currently do.

Chris - It seems like all of these issues related to transport come down to batteries and energy supply. It’s like we’re at the precipice here and we really need to solve this problem. And no one's yet managed to get over this chasm of how we get enough energy packed into something that doesn't weigh more than the aeroplane at the moment and all its fuel and all its passengers. The problem is they’re just so heavy, as you say. And it’s holding back technology for phones, it’s holding back technology and other communications devices, it’s holding back technology for cars and so on.

Tim - Yeah. In terms of things like cars and even trucks and also boats, they are perhaps more promising than electric planes because the weight isn't as much of an issue. Yes, you still have to get going, but actually once you get going keeping it going is not nearly as hard as it is to keep something in the air, or to get it into the air in the first place. We’re already seeing electric cars making it onto the streets, and there are the first examples of electric trucks and also electric boats that might be able to clean up those industries before we start cleaning up planes.