Making sense of the hydrogen hype
Jules Verne was right: the future will be powered by water
I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable.
People have been talking about water as a source of power since Jules Verne dreamed up a society fueled by hydrogen in his 1875 book The Mysterious Island.
Having never paid attention to chemistry or 19th century sci-fi in school, I saw hydrogen as just a gas, and a particularly boring one at that (unlike its big brother helium which is definitely not boring.)
But hydrogen is a fuel, and the promise is exciting indeed. The process for making it is well understood and, provided the energy used in the process is clean, then it is an entirely green power source. It is produced by running electricity through water which splits the H2O molecules into hydrogen and oxygen, a process called electrolysis. The resulting H2 gas can be stored and transported and it can be burned to create energy. The residue of the combustion is pure water vapor.
Hydrogen could, the logic goes, be used to replace fossil fuel use just about everywhere: to power industrial processes, to make fertilizer, to heat and cool buildings, and to fuel all transportation. That all sounds too good to be true, and it is, for reasons I describe below. Even then it remains the case that hydrogen is incredibly exciting and deserving of the hype as the fuel of the future.
Hydrogen today
We already make a lot of hydrogen gas but almost all of it by using a process called steam reforming where hot water steam is mixed with methane or another hydrocarbon. It is a very carbon intensive process. From Wikipedia:
Hydrogen is required for many essential chemical processes. In 2020, roughly 87 million tons of hydrogen was produced worldwide for various uses, such as oil refining, and in the production of ammonia (NH3) and methanol (CH3OH), and also as a fuel in transportation.
Electrolysis (performed by devices called electrolyzers) holds the big promise for producing hydrogen cleanly as long as it can be powered by renewable energy. By some estimates the world will need 3,500 Gigawatts of electrolysis by 2050 to get to net zero while today production sits at less than 1GW.
Hydrogen is colorful
Actually it isn’t. But now I have your attention, don’t I?
The most abundant, simplest, and lightest element in the universe is colorless, odorless, tasteless, and non-toxic. It is of course flammable (the whole point of a fuel is that it burns) but less dangerous than other fuels: it is lighter than air so any leaks are likely to float up and quickly disperse.
But if H2 is invisible, then what is all the fuss about green, blue, gray, and even pink hydrogen? The image and link below go into detail but suffice to say that for the purposes of decarbonization the only type that matters is green hydrogen: the one produced with renewable energy. All other colors are largely a distraction, even the much hyped blue hydrogen which is produced by steam reforming using carbon capture and storage. But CCS can never capture all the emissions and any lifecycle analysis would deem the carbon intensity in blue hydrogen as still quite high.
Limitations mean that hydrogen will not solve everything
By the time that hydrogen has been produced and delivered to where it is needed it could have only 30% of the energy it started with. More than 60% of the energy content gets lost along the way of the production and supply chain. This is compared to around 20% inefficiency of using batteries.
Production is inefficient:
There is up to a 30% loss in energy in hydrogen production through electrolysis. That poses a question: why bother making hydrogen instead of just using the input energy source itself? The answer is that hydrogen is a way to store and move energy around, and in a different way from batteries.
To produce all the green hydrogen needed to reach net zero targets we first need to manufacture the electrolyzers. And there could be problematic bottlenecks like reliance on rare minerals like iridium and platinum.
Transportation is difficult:
Hydrogen is the most energy dense fuel measured by weight but it requires more volume to carry the same amount of energy compared to gasoline or jet fuel. That is why some hydrogen powered airplanes look weird.
The same means of transportation used for liquefied natural gas (LNG) can also be used for hydrogen but it would still be up to 5x more expensive by unit of energy. That high cost is due in part to the larger volume but mostly because liquefying hydrogen takes 30% of the energy in the hydrogen itself since it needs to be pressurized and cooled to -240 °C (only 33 Kelvin!)
Ammonia can be used as an energy carrier allowing for easier transportation (it can be liquefied at a relatively warm -33 °C) but that requires additional energy at the other end to convert back to hydrogen. The shipping industry is betting on ammonia itself as a fuel to avoid that last inefficient step.
To avoid liquefying, hydrogen can be moved as a gas via pipelines. Existing methane pipelines can be converted for that purpose and that would be cheaper than building new infrastructure. But there are problems including increased risk of leaks given how tiny the H2 molecule is.
A more realistic role for hydrogen in decarbonization
All considering, hydrogen will be key in a decarbonized economy. In short, its place can be described as an alternative to batteries where batteries are impractical or impossible. I see that as the following:
Hard to decarbonize manufacturing like steel and cement that need a very dense source of energy to create a lot of heat. Hydrogen can be shipped to facilities as a liquid or even produced in situ.
Long-distance transportation: shipping, aviation, and rail. Basically in places where the refueling infrastructure footprint is more manageable. Some (hello, Toyota!) still hope for hydrogen fuel cell vehicles (FCEV) with their longer ranges and shorter refueling times compared to batteries but that would require an entirely separate infrastructure to supply hydrogen to a huge network of fueling stations. Plus, fuel cells are basically electrolyzers and we don’t want more market competition for those rare materials as that could hurt large scale hydrogen production.
Clean up fertilizer production. Ammonia plays an important role in making fertilizer so to a certain extent the decarbonization of agriculture relies on a quickly switch to making ammonia exclusively from green hydrogen.
But making green hydrogen will require a lot of spare power that can be deployed towards an inefficient process and we already need all the renewable power we can get to replace fossil fuel electricity everywhere. Will there be enough green power to make hydrogen?
Here the main downside of solar and wind power could be a big plus: when the sun is shining at its brightest and the wind blowing at its strongest, we typically produce more power than we can use. All that surplus power needs to be used, stored, or wasted. Some of it will be stored in batteries. But some of it could be stored as hydrogen.
Places with plenty of renewable resources like Brazil (called out by McKinsey as one of the most competitive in the world) and Australia (with plans to be the Saudi Arabia of green hydrogen) have a bold hydrogen strategy in place to harness abundant sun and wind to become major exporters of hydrogen to the world.
Expand your knowledge:
Watch hydrogen being burned. Not only is H2 gas invisible but — incredibly — its flame is also invisible! Is this awesome or what.
Listen to a discussion about the market dynamics of hydrogen production in Europe vs. the United States. It seems that with new incentives in the IRA the US is about to steal the hydrogen wind from under Europe’s sails.
Read about clean fuel alternatives to green hydrogen in long distance transportation:
How the shipping industry is betting on ammonia as part of a cleaner energy mix
Forget electric cars, the future of battery technology is in airplanes
Fleetzero begins its search for the first giant ship to convert to battery power
And last, and definitely least, Toyota secures funding to develop hydrogen fuel cell versions of its Hilux pickup in the UK (for some reason Toyota keeps doubling down on fuel cell cars. I can’t see how that effort could succeed given next to no movement elsewhere)