Hydrogen can be used as a fuel when it’s burned with oxygen. But what makes hydrogen special is it’s a zero-carbon fuel, so it could be a game changer in the mission to make transport reach its net zero goals. You can use hydrogen in fuel cells or internal combustion engines. Hydrogen has already been used in commercial fuel cell vehicles, such as cars and buses, and it’s also been used as a fuel in spacecraft propulsion. Let’s look at the possibilities of hydrogen as a sustainable fuel to solve some of our main challenges in making transport more sustainable.
Hydrogen is one of the most abundant elements in our universe, and when burned, the only waste produced is water and heat. Using hydrogen in transportation is not a far-off fantasy or science fiction, as hydrogen fuel cells have been around for decades, and even now, hydrogen-powered vehicles are running in California.
Cars can also use hydrogen as a straight-up fuel, where hydrogen gas is used as the energy source to power the vehicle’s engine, producing electricity and propelling the car.
To understand the use of hydrogen, let’s talk about the two main ways it can be used. First, hydrogen can be used in combination with traditional gasoline in internal combustion engines, which is not ideal, but still can reduce emissions drastically. Secondly, hydrogen can be combined with oxygen that’s in ample supply in our air to create hydrogen-powered fuel cells that generate electricity and propel the car that way.
How do these two ways work?
Fuel cells use chemical energy from hydrogen or other fuels to generate electricity. They are unique in that they can use a wide range of fuels and provide power to satisfy a range of energy demands, from something as small as a computer to as large as a power station. A fuel cell works like a battery but never needs recharging. As long as fuel is supplied, the fuel cells will continue producing electricity.
Just like with a battery, they have a negative electrode (an anode) and a positive electrode (a cathode), which surround an electrolyte. When you use fuel like hydrogen, this is fed to the anode, while air (oxygen) is fed to the cathode. Hydrogen is split into its protons and electrons using a catalyst at the anode. The electrons take a different route in the cathode to the protons, and the electrons create a flow of electricity through the external circuit. On the other hand, the protons unite with oxygen and produce water and heat.
German automobile manufacturer, BMW, built the world’s first hydrogen internal combustion engine operated in a passenger car between 2005 and 2007. This engine was an internal combustion engine that used hydrogen as a fuel source directly, and not fuel cells. The Hydrogen 7, BMW’s hydrogen-powered car, had two tanks–one for traditional gasoline and one for hydrogen–and the fuel could be switched. This means the car could run even if refuelling with hydrogen was unavailable. Although there are few hydrogen-refuelling stations, BMW produced more than 100 replicas of this car, but the vehicle is not available on the commercial market yet. However, there’s a lot of potential in the technology for using hydrogen fuelled-internal combustion engines.
Firstly, converting conventional gasoline motors to those that can operate on hydrogen as fuel requires little change. The main changes concern the inlet system and a new hydrogen dispensing valve. In the Hydrogen 7, an additional pipeline was installed alongside the gasoline one. A second tank also needed to be installed to accommodate the hydrogen, which could be introduced directly into the combustion chamber under high pressure.
Another benefit is that, unlike electric operation, hydrogen propulsion does not require using rare metals or heavy electric motors. The technology is being used more and more. In Europe, even trucks are being tested with hydrogen internal combustion engines, as it looks like hydrogen could solve the problem for long-distance transportation.
The main benefit of using hydrogen in transportation is its clean energy; the only waste products from using hydrogen as a fuel are water and heat. This makes hydrogen a zero-carbon emission, clean, and sustainable fuel.
Hydrogen is one of the most abundant elements in the universe. It can also be produced using various processes, like thermochemical processes using heat and chemical reactions to release hydrogen from organic materials, biomass, or even water. You can even split hydrogen from water using electrolysis or solar energy. And you also have microorganisms like bacteria and algae that can extract hydrogen through biological processes. This means that hydrogen can be a readily available fuel source.
Also, hydrogen is very energy efficient and may even be more so than fossil fuels. It’s a very versatile fuel, depending on the mechanism. As we can see, it can be used even in dual-tank vehicles, which can use both hydrogen and fossil fuels in the internal combustion engine.
There is still some way to go before we can ultimately move into hydrogen-powered vehicles in the mainstream.
Although there are many ways hydrogen can be extracted, these also require energy for the most part. One of the main ways to extract hydrogen is from fossil fuels, which can make it counterproductive to sustainability goals. There may be greener and more energy-efficient ways to extract hydrogen, but it could take some time for the technology to make it viable on a mass scale.
Storing hydrogen can also be a challenge, as hydrogen is more complex to store than fossil fuels, not to mention it’s also very flammable, which raises some safety concerns.
It’ll take more research, innovation, and even regulatory developments before hydrogen can be ready for mass adoption. More investment and development are needed to make the technology available, but all things point to hydrogen being a tool we can use to decarbonise transport.
As we’ve seen, the outlook for using hydrogen as a fuel for internal combustion engines shows promise. These engines can be made to adapt to different fuel sources, and our client, Carnot, is doing precisely this. They are producing fuel-agnostic powertrains, which can be a sustainable compromise for long-distance transport like heavy-duty vehicles and marine. These engines can adapt to different fuels, so they can use hydrogen or hydrogen-ammonia blends, but they can also be used with biofuels, e-fuels, and even traditional fuels. If we can envision hydrogen fuels as the future, these engines could be the perfect stepping stone to help decarbonise transport.
The good news is that there are many promising technologies in development–closer than we think–that can help us reduce our emissions and reach net-zero emissions. Hydrogen is one of the more exciting developments, and its commercial use might even be closer than we think.