10 years ago, electric cars seemed like something of a distant future; now they're everywhere. Tesla was one of the first companies to start the hype and now almost all car manufacturers present more and more electric cars. If we've come along this far with cars can we translate the concept to planes? Can we just stuff some batteries into our planes and replace the turbines with electric engines? Let’s have a look at the future of electric aviation and its potential to make flying green.
When one thinks of green energy, solar power is one of the first forms of production that comes to mind. We can power our houses, charge our phones and even run a cinema with the sun, can't we use it to fly around as well? Well, yes and no.
Not so long ago we managed to fly around the world in a solar-powered aircraft. Everyone had their doubts: Would the plane take off? Would it be able to finish its trip around the world? Well, it did but rather slowly. It took pilots Bertrand Piccard and Andre Borschberg 505 days to complete the journey. For most distances, the solar plane defied the idea of flying — you know, speed — because its cruise speed was much lower. What is more, the plane had a wingspan close to a jumbo jet but would only carry one person: the pilot. So in order for solar-powered air travel to become commercially viable, we would need to develop some extraordinary solar panels and more efficient planes.
You could argue that not all electric cars don’t run on solar panels but rather batteries. So can we just put some batteries, similar to the ones in cars, in our planes? The most crucial difference between ground and air travel comes into play when considering electric planes. When you're traveling on the ground the weight of the vehicle is not your most crucial concern. The energy is mainly used to move the car forward and work against the wind resistance. This isn't the case for airplanes. A large portion of the energy is used to lift the plane up in the air. In fact, the heavier is the plane the more energy is needed. It is therefore important that the fuel doesn't make the plane significantly heavier.
When it comes to fuel, the way to measure it is the energy density, which describes how much energy you can store per weight unit. Sadly batteries have a much lower energy density by 14 to 40 compared to kerosene. So if we were to put batteries on planes they would get much heavier and – if they flew at all – carry less weight. And there is a further drawback: with kerosene airplanes, fuel is burned during a flight so the plane gets lighter over course of the travel. Batteries, however, keep their weight which means higher energy consumption through the flight and a much bumpier landing. An electric aircraft would need a considerable increase in battery capacity and performance; according to industry projections, this doesn't seem like it's going to be happening in the coming few years.
At this moment in time, electric planes are no feasible alternative in commercial aviation if we don’t want to put them on a power cord, but surely someone thought the Wright Brothers were also bound to fail. All hope is not lost on the future of flying green, we just need to get creative.
This article was written by Eric Schuler for Kinder World in light of the upcoming Kinder Conversations event on the future of green aviation: The Sky Has a Limit. Schuler is a PhD candidate at the University of Amsterdam and works on new industrial sustainable chemistries to turn captured CO2 into useful things such as plastics or fuel. He's also a photojournalist with an interest in climate and land-use change.