Hydrogen: Artificial Photosynthesis & a Clean Fuel
13 minute read
Updated on Sun Aug 29 2021
In the last chapter, we saw that batteries allow us to replace 71% of oil-based fuels with electricity. This is for cars, trucks, and other land transport, but batteries can’t hold enough energy per kg to make airplanes or ships electric.
In nature, hydrogen (H) usually appears as a pair of two atoms (H₂). This is also true for oxygen (O₂).
Water (H₂O) is made of hydrogen and oxygen. You’ve probably never seen water fall apart into H₂ and O₂, right? That’s because water is a stable compound. Splitting H₂O requires energy. Therefore, we can store energy by splitting water (2H₂O) into 2H₂ and O₂ and later get the energy back by bringing them back together.
Fuel from water?
How is hydrogen produced today?
Why use gas over renewables? Cost. But with innovation and further deployment of solar and wind, we could get costs down by a lot:
What needs to change?
Higher electrolysis efficiency: The more hydrogen per unit of energy, the better!
Higher compression efficiency: Every unit of energy we spend on compression essentially goes to waste, but we need to compress hydrogen to fit it into tanks. It's a gas, in the end.
Higher fuel cell efficiency: The more energy we get out of each kilogram of hydrogen, the better.
Infrastructure: Gases are hard to transport. To avoid the huge upfront cost of building pipelines, H₂ could be produced near to where it’s used. This is a trade off because building many smaller electrolyzers would likely be more expensive than a few big ones.
Can Artificial photosynthesis help?
What if we could do what plants do to make energy, but do it better?
Price & hydrogen’s battery trap
For example, to make one bag of chips, you need to build a potato farm and a chip production factory. If you then make 100,000 more bags and divide the initial cost among them, each of them gets cheaper!
Making production, compression, storage, and transportation of hydrogen cheaper could have a massive impact on the whole energy ecosystem and, as a side effect, would help avoid the 2% of global emissions coming from hydrogen production today.Next Chapter