These days, with the importance of furthering the fight against climate change, more and more different options are being explored. Making the transition to clean renewable energy is one of the centerpieces of our net zero future, and one of these potential sources is hydrogen energy.
The International Energy Agency (IEA) projects that from here out to 2050, hydrogen energy will play a small but noticeable role. It accounts for 6% of the cumulative emission reductions needed to hit our net zero targets by mid-century. But what is hydrogen energy, exactly? And what does it do that other sources of clean energy can’t do right now? Let’s start with the fundamentals of hydrogen energy: how does it work?
Hydrogen Fuel: The Basics
The first thing to know about hydrogen energy is that hydrogen is a fuel. What that means is that like other fuels, such as coal or natural gas, we can burn it to create energy. However, when burned in a fuel cell, the only emission from hydrogen energy is water. Unlike fossil fuels that emit greenhouse gasses, hydrogen fuel can burn 100% clean – or mostly clean, depending on how it’s done. In a hydrogen fuel cell EV or FCEV, hydrogen is burned with pure oxygen in specially made cells to create water. However, there’s also a type of hydrogen vehicle called the hydrogen internal combustion engine vehicle, or HICEV.
HICEVs are actually very similar to our current, commonly used gas-powered vehicles. Indeed, many HICEV prototypes have simply been modified versions of previously existing vehicles, as shown below: HICEVs burn hydrogen fuel with air in order to generate energy. Since there’s no carbon in the fuel, no carbon dioxide is emitted in the process. However, since air contains nitrogen, the byproducts from burning hydrogen in an HICEV include nitrogen oxide (NOx) alongside water. And while NOx isn’t a greenhouse gas, it’s an air pollutant that contributes to smog. And while traditional gas-powered vehicles produce significantly greater amounts of NOx, the fact that HICEVs produce some as well means that they’re not true zero-emissions vehicles – even if this can be mitigated with catalytic converters much like in a regular car.
Even with that taken into consideration, however, both FCEVs and HICEVs produce zero carbon emissions, which are the main focus of our net zero transition. As a result, hydrogen is being considered for use in vehicles as a replacement for traditional gas-powered internal combustion engines, alongside electric vehicles (EVs).
Why Hydrogen Fuel?
Now, you’re probably thinking – EVs are everywhere, and chances are pretty good that your local dealership has several on their showroom floor, whether they’re plug-in hybrids or fully electric battery EVs. But if you’re reading this article, there’s a good chance you’ve never even heard of hydrogen-powered cars. Much less be able to drive one off a lot yourself (unless you happen to live in China, Japan, South Korea, or Germany). Haven’t EVs already established themselves as the dominant replacement option for gas-powered cars? What could hydrogen bring to the table that EVs can’t offer?
Here are some of the major advantages and disadvantages of FCEVs and HICEVs (referred to as H2-ICEs in this table) vs. traditional EVs, as well as a fourth option: biogas/synthetic fuel:
As you can see, regular EVs and FCEVs share many of the same advantages and disadvantages. But HICEVs are slightly more advantageous on a couple of measures as a trade-off for not being 100% emissions-free vehicles. One thing not mentioned in the table above is that hydrogen vehicles generally have the same range as their traditional gas-powered counterparts. In contrast, battery EV owners must shell out the big bucks if they want their vehicle to have a range competitive with that of a regular car. These longer-range EV batteries would weigh more, in turn causing the vehicles to use more energy. Hydrogen fuel’s energy density is significantly higher than that of batteries. As such, a hydrogen vehicle of equivalent range would weigh much less than the battery EV equivalent. A longer-range battery EV also directly translates to a longer charging time. In contrast, refilling a hydrogen vehicle is essentially identical to how you fill up your car at a gas station.
In summary, hydrogen vehicles, and HICEVs in particular, offer a number of competitive advantages over battery EVs. But they do have their own disadvantages too. Hydrogen fuel is more difficult to store than electricity, for instance. The main barrier to mass adoption for both EVs and hydrogen vehicles is that they require extensive build-out of refueling infrastructure. But EVs do have an advantage in this regard as many battery EV owners can recharge their vehicles at home, even if the process is slow. That’s why battery EVs are winning – at least for now.
How Do We Get Hydrogen Fuel?
That battery EVs can be charged at home is perhaps the biggest advantage battery EVs have over hydrogen vehicles right now. Electricity is all around us and part of our daily lives. Hydrogen fuel, however, would require production and distribution facilities just like how gas stations need to get their gas from refineries and bulk storage terminals. Unlike oil, however, hydrogen doesn’t naturally form in large quantities on Earth. There aren’t any hydrogen formations we can drill down into to start producing from. Instead, hydrogen fuel needs to be produced through manmade processes.
There are two main methods of hydrogen production: from natural gas, and from water. The former is known as blue hydrogen. This type of production usually combines methane from natural gas with high-temperature, high-pressure steam to form hydrogen and carbon monoxide. This process is known as steam methane reformation. Currently, this is how the world gets most of its hydrogen. However, since methane contains carbon, inevitably we end up with carbon emissions. That would mean we need some method of capturing and storing the carbon emissions to make this hydrogen a clean energy.
However, hydrogen can also be produced from the electrolysis of water, which is…