Electric batteries, hydrogen fuel cells, and fossil fuels: What will propel AAM?

Giovani Izidório Cesconetto

April 5, 2022

Electric Batteries, Hydrogen Fuel Cells and Fossil Fuels: What will propel AAM?While conventional air mobility runs mostly on fossil fuels, the industry builds Advanced Air Mobility (AAM) around greener solutions like electricity and hydrogen. But that raises more questions than answers, like, are these new technologies more sustainable than fossil fuels? And how well do these new types of energy differ from what we currently use? Read on to learn more about each of these three types of fuels.

Fossil fuels

Even though it’s true that we should run away as fast as possible from fossil fuels, the reality is they’ll be an essential part of aviation—and society—for years to come. However, this doesn’t mean that there’s absolutely nothing we can do to mitigate fossil fuels’ environmental impact.

For example, hybrid-electric aircraft have already arrived, such as, also known as aircraft, which use both fossil fuel engines and also an electric engine. Before plug-in cars, there was the Prius. So why should AAM think of going straight from fossil fuels to zero-emission aircraft? Of course, today’s batteries are way better than they were back in the 1990s when Toyota launched the first Prius, but as we saw, electric batteries still aren’t as efficient as they need to be for commercial aviation.

Hybrid-electric aircraft can burn up to 40% less fuel than conventional aircraft. That’s already a considerable reduction in GHG emissions. Hybrid-electric aircraft also have more range than purely electric. For example, Electra Aero’s aircraft can fly as far as 805 km with a cruising speed of 321 km/h, needing only 48 km/h and 30 meters to take off and land—making it a STOL. And just like cars, once batteries improve their efficiency, AAM can move towards innovating electric commercial aircraft.

And hybrids aren’t only a solution to speed up the zero-emission future; they can also speed up the hydrogen future. ZeroAvia is heavenly investing in hydrogen-electric aircraft. The company knows that a 100% hydrogen aircraft isn’t possible today, but a hybrid is.

Hybrids are important to AAM because they offer a path to be followed, a timeline almost. It starts with fossil-electric, goes to 100% electric, advances to hydrogen-electric, and gets to 100% hydrogen. With these steps, the transition to a zero-emission AAM becomes more accessible and faster.


Electric batteries, including state-of-the-art lithium-ion batteries, are already commonly found in the electronics in your home. They’re mass-produced, and unlike hydrogen fuel cells, lithium-ion batteries are easy to build with today’s technology.

The problem electric batteries currently have for aviation purposes is the energy density. These batteries only have around 1% of the power “punch” by weight compared to existing fossil fuels. , This means that aircraft would need to have much more of the weight they can carry dedicated to fuel instead of people or cargo. 

Another problem with electric batteries is that they are only as clean as the energy coming “from the wall.” Suppose electricity is green (hydro, solar, wind, etc.), then, consequently, it’ll be a zero-emission aircraft; however, if the energy comes from coal, fossil fuel, etc., the aircraft won’t be zero-emission, even if the aircraft itself isn’t polluting. It’s also worth noting that batteries often require rare earth metals for building, we don’t have a great way to recycle them yet, and they don’t last forever.

But there are good things about electric batteries as well. They already exist, are already produced on a large scale, are relatively cheap to produce, have many researchers making them better daily, and there’s no GHG emission while operating. So while hydrogen fuel cells will always be a better long-term solution, electric batteries are the bridge that connects today with tomorrow.

When we talk to experts worldwide looking at aviation and the potential applications of batteries, many tell us that electric batteries will forever change the future of short-haul travel. Longer trips may require other fuel sources, like hydrogen.


Hydrogen has a far greater energy storage density than lithium-ion batteries (considered the best currently available electric batteries), offering a significant range advantage for electric aircraft while also being lighter and occupying less space.

Another edge is that you can refuel hydrogen-powered aircraft in just a few minutes by pumping hydrogen into the aircraft—similar to how you’d pump gas for your car—, while battery-powered aircraft requires a wait while the battery charges—granted, this process is getting quicker and more efficient by the day; however, it’s essential to recognize that there still is a long road ahead.

And unquestionably, the best part of hydrogen is that, in the end, it generates only water—no greenhouse gases (GHG), no pollutants at all, only water.

The problems with hydrogen are the technical challenges. Since it’s a new technology, creating hydrogen is still expensive, and the capacity to grow production is limited. And even though the end result is water, it currently takes a significant amount of energy to make fuel cells, And this energy doesn’t always come from the greenest place.

Let’s take a moment to understand the different types of hydrogen. Hydrogen is a colourless gas, but depending on its production, it receives colourful names.

Grey hydrogen uses fossil fuels, such as natural gas, in its production and releases CO2 during the process; this is the cheapest and most common source of hydrogen today.

Blue hydrogen also uses fossil fuels in its production, but the CO2 is captured during the process, limiting the GHG emissions; this method is more expensive than the previous and therefore less common.

Green hydrogen uses only renewable energy sources in its production. Because of that, it is both the cleanest form of hydrogen and the most expensive way of producing hydrogen.

Will AAM reach net-zero emission?

The answer is “yes.”

But like every simplistic answer to a complex question, it doesn’t tell the whole story, nor is it entirely correct.

The more correct answer would be, “AAM has the potential to reach net-zero emissions, but the countries will have the final say on the matter.” And why is that? Because as we saw in this article, AAM aircraft are only as green as the energy propelling them. An AAM aircraft won’t be 100% zero-emission just because it uses electricity, hydrogen, or both. Sure, the aircraft itself won’t be actively polluting, but if the electricity or hydrogen comes from fossil fuels, the aircraft will be indirectly polluting.

So for an AAM aircraft to be 100% zero-emission, there’s no margin for pollution at any steps along the way. That’s why countries will have the final say and why Canada is in an excellent position to have a zero-emission AAM future. As JR Hammond, Canadian Advanced Air Mobility Consortium (CAAM) Founder & Executive Director, says in this interview, Canada is one of the few linked and organized countries in the world.

And in this interview, JR explains what he understands for “linked and organized,”

Canada’s advantage is that we are very structured and organized; TransLink has jurisdiction over thirteen cities in Metro Vancouver, for example. So reaching consensus is easier, and the implementation is also more straightforward because when TransLink decides something, it implements it across the board.

And as Dr. Fatih Birol, International Energy Agency’s (IEA) Executive Director, stated in his foreword of the Canada 2022: Energy Police Review report remarked,

Canada’s electricity supply is among the cleanest in the world, thanks largely to the dominance of hydropower and the important role of nuclear. Greater interconnections among provinces and territories can ensure balanced progress towards national goals for decarbonizing the power sector. Steeper emissions reductions are still needed in other sectors, notably oil and gas production, transport and industry. To this end, Canada has focused its efforts on a number of technologies, including carbon capture, utilization and storage; hydrogen; and small modular nuclear reactors, to serve as a supplier of energy and climate solutions to the world.

Since provincial cooperation can be easier in Canada than in other countries, Canada has a better chance of increasing its already clean energy production, making the country a perfect place to see AAM reaching net-zero emissions sooner than later. Other countries that aren’t as linked, structured, and organized as Canada will probably also reach a zero-emission future, but it’ll take them more time than Canada.

Click here to know more about how CAAM and Canada build a zero-emission future.

By Giovani Izidorio Cesconetto