As you might already know, the E in eVTOLs stands for electric. Knowing this, it’s fair to ask, are eVTOLs sustainable, and how will eVTOLs affect the environment?
On the surface, the answer might seem straightforward. However, it’s actually quite complicated when you bring together the factors involved. So, let’s look at whether eVTOLs are sustainable.
What Do We Mean by Sustainable?
This might be an obvious place to start, but to answer the question, are eVTOLs sustainable, we must first explain what we mean.
Sustainable means maintaining something at a set rate or pace. In relation to sustainable travel or vehicles, we’re referring to carbon emissions and greenhouse gases.
In short, a sustainable vehicle doesn’t contribute to carbon emissions. Electric cars, on the surface, are sustainable. Petrol vehicles, however, aren’t.
Are eVTOLs Sustainable?
Now that we understand what we mean by sustainable, we can consider whether it applies to eVTOLs. For an overall picture of a vehicle’s sustainability, we should consider everything from design and production to sale and use. However, to keep this article at a reasonable length, we’re only going to focus on production and use.
The eVTOL Powertrain
A vehicle’s powertrain includes all the components that make it move. For an eVTOL, this would be the battery, engine, and propellers. Of course, it’s more complicated than that, but we don’t need to go too deep into the science.
eVTOLs run on lithium-ion batteries, which are just bigger versions of the battery in your smartphone. And, like your phone, these batteries must be charged.
This is where the first question of sustainability pops up. After all, we can only consider an electric vehicle truly sustainable if it receives energy from a renewable source. If it’s charged using fossil fuel power, it’s not really achieving much.
Plenty of concepts for vertiports (eVTOL stations) include solar panels. These will charge the eVTOLs’ batteries, meaning this aspect will at least be truly sustainable.
You can check out this video for a deeper look at how an eVTOL powertrain works.
eVTOLs and Hydrogen
Some eVTOLs will instead use hydrogen fuel cells. While they won’t be truly electric, it’s not dissimilar to the upcoming change to the Toyota Prius, which will feature a hybrid engine. It’s both gas and hydrogen powered. These eVTOLs will be the same, just with electric.
Hydrogen is often viewed as a perfect alternative to gasoline engines because its only waste product is water. However, it’s not all as green as it seems.
There’s something called the hydrogen color spectrum. It refers to different ways in which we produce hydrogen, as it needs to come from somewhere. The most common form of production is gray hydrogen. This is where it’s produced using natural gas, which results in greenhouse gas emissions.
Green hydrogen is, of course, the goal. As you can probably guess, it’s produced using renewable energy sources. These power hydrolysis machines, which split hydrogen from water. Unfortunately, the process is very expensive but should become more common in the future.
So, like charging batteries, there’s much more to dig into when it comes to power sources. When looking at the question, are eVTOLs sustainable, the answer is no until their power comes from fully renewable sources.
How Will eVTOLs Affect the Environment?
Looking at the sustainability of eVTOLs means focusing on use. But looking at their environmental impact means considering their production, too. First, we’ll cover their impact during use, as that’s what we’ve been discussing.
eVTOLs and Emissions
During the concept and development stages, eVTOLs were seen as a truly sustainable alternative to road vehicles – both electric and gas-powered.
However, a study from 2019 found that eVTOLs might actually do some damage. It tested electric planes and cars over a 100km journey to see which was better for the environment.
The test showed that electric cars produced 28% less greenhouse gas emissions over that distance. For journeys longer than 100km with 3 passengers, though, eVTOLs were 6% more efficient than electric cars.
This is because of how much power it takes to fly vertically. Once in cruise mode, eVTOLs are pretty efficient. The study concluded that journeys of less than 35km are pointless in an eVTOL, but anything over 100km is worth it from a sustainability perspective.
So, when looking at the question, are eVTOLs sustainable, much of it depends on their purpose. Long-range eVTOLs seem to address the sustainability issue far more than UAMs. However, this might change in the future as technology improves.
Production: How Will eVTOLs Affect the Environment?
We could go into a lot of detail about how will eVTOLs affect the environment in terms of production. But the main thing worth focusing on is lithium, as it’s a very interesting story.
Lithium is used in rechargeable batteries. Your phone battery will have up to 3 grams of lithium in it. That battery weighs around 32 grams. An eVTOL battery, however, can weigh anywhere between 200kg and 600kg. That’s a lot of lithium.
Mining lithium is an incredibly dirty (but profitable) business. It’s pumped out of the ground using water before it’s processed. To get 1 ton of lithium, you need around 500,000 gallons of water.
It doesn’t help that one of the biggest lithium reserves is under Chile’s Atacama salt flats, an area notoriously short of water. Mining efforts impact local communities by basically stealing their water.
And that’s not even considering the carbon emissions involved. In 2016, lithium mining companies produced 211.3 million tons of CO2. Considering lithium is a cornerstone of electric vehicles and aircraft, this is a pretty big source of environmental damage.
Putting it All Together: Are eVTOLs Sustainable?
So, now we can come up with a better answer to how eVTOLs will affect the environment. Providing they’re powered with completely renewable energy and only fly journeys longer than 100km, their impact will be largely positive.
But, for now, this is probably just a pipe dream. We don’t have the kind of battery density and renewable energy sources needed to make eVTOLs a fully green concept.
That’s not to say it can’t happen. Much like how electric cars went from 20-mile trips to nearly 400 miles, eVTOLs will hopefully become much more sustainable in the future. We are still in the early stages of technology, after all, and it’s come a long way in a short time.