If you've read Hydrogen Production 101, you're now familiar with "SMR" and "WGS." The other method we're going to discuss today is called electrolysis. It’s really simple: add electricity to water and it splits into hydrogen and oxygen.
No carbon means no carbon dioxide. No fossil fuels. No pollution, and no global warming. This is fantastic: we can create a fuel – pure hydrogen – that is 100% renewable and sustainable!
We also see that hydrogen from electrolysis is simply a way to convert electricity to another form. Electricity by its nature is fluid, it’s dynamic, always moving. The only way we can directly save it for later is with batteries. But batteries, even the most advanced kinds today, can reach immense sizes and costs to store the amounts of energy needed for industrial or power generation applications. Hydrogen is a way to store electricity in a much lighter, more compact, and – key point – more transportable form. This is why hydrogen is sometimes called an “electrofuel.” The image of hydrogen as stored electricity is a powerful and useful one when trying to understand its importance and potential.
We have to be careful, though, because the electricity to make hydrogen via electrolysis has to come from somewhere, and if we use electricity created from fossil fuel power plants we haven’t really gained much; it kind of defeats the purpose. What we want to do is create electricity from a 100% renewable and sustainable source, and that source is the Sun. The photons in sunlight can make electricity directly though solar photovoltaic (PV) panels. The heat of the sun causes temperature differences on the earth’s surface leading to wind, which in turn also leads to waves; it evaporates water and causes precipitation which enables hydroelectric power; and it can be focused to boil water and make electricity through generators powered by steam.
Sunlight and wind occur everywhere on earth in varying degrees, waves happen everywhere there are bodies of water, and hydroelectric power is available wherever there is precipitation and differences in elevation. This is another important distinction from fossil fuels, which are concentrated in various underground deposits, because it means we can make renewable electricity – and thus renewable hydrogen – anywhere on the globe! And compared to the machinery and complexity needed to extract oil, gas, or coal from the ground and process it to usable fuel, solar energy is so easy and simple to capture that a two-year old can create electricity – and thus renewable hydrogen – just by holding a small solar panel out their window.
Creating hydrogen everywhere in the world is not just possible, but desirable. Hydrogen production facilities that use fossil fuels, as we saw above, are based on chemical reactions at high temperatures. These kinds of plants are most efficient – both from an energy standpoint and a cost one – when they are very big. Combine that with the fact that over 90% of hydrogen produced today is used by just two industries, crude oil refining and ammonia production, which also needs to be done in very large plants, and it starts making sense why today’s hydrogen production is limited to fossil fuel-based methods in a few large facilities.
But as we transition to the widespread use of hydrogen for industry, for homes, and for transportation we now have the option to create hydrogen anywhere, by anyone. Imagine every house or apartment complex capturing solar energy and using small electrolyzers to convert that to hydrogen, which you then use to fill your car. The scenario can be repeated at businesses, manufacturing plants, train depots, farms; the list goes on and on. If you create more hydrogen than you need, you can sell it to your neighbors for some extra income.
It’s not just individuals who can benefit from this. In our work over the past few years we have had discussions with municipal and national governments around the world about strategies to combine their solar energy resources with hydrogen production to not only eliminate the need for fossil fuel imports, but to also turn an energy importer into a clean energy exporter. There are immense beneficial implications of this scenario for governments.
Because electrolyzers do not rely on high temperature chemical conversions, they are not affected by economies of scale and thus enable these visions to occur. It becomes much more efficient from a cost and energy perspective to create the hydrogen where it will be used, and this also allows us to capture more of the solar energy given to us (for free) every day by our Sun.
Uh-oh, I can hear the entrepreneur in me laughing. “It seems like the engineer has just concluded that hydrogen not only can, but should be found under every rock in the world,” he smiles. “Can we keep marketing hydrogen as, ‘the most abundant element in the universe’ then?”
I’m not sure I’m ready for that quite yet. Let’s try: “Hydrogen enables the world to completely remove fossil fuels from its power mix and rely exclusively on the sustainable, renewable power of the sun to meet all of our energy needs.”
The marketer groans…