As far as fuels are concerned, hydrogen is just about perfect. When combined with oxygen in a fuel cell, just three things come out: electricity, water, and heat. That’s it. No carbon dioxide. No particulates. No worries about sinking public health or rising sea levels. It’s the fuel you can bring home to meet your parents.
In fact, there’s really only one reason hydrogen isn’t keeping your lights on and ferrying you to the supermarket right now: it’s neither simple nor clean to make. Unlike fossil fuels, we can’t drill or dig for hydrogen. While it’s the most abundant element in the universe, it’s also one of the lightest. So here on Earth, free hydrogen immediately ascends to the heavens. Any hydrogen that sticks around does so because it’s bound up in other things, like water and methane, which means that to get hydrogen for your fuel cell, you have to separate it from compounds that contain it. There are several ways to do this, but they either consume more energy than their hydrogen creates, or they release greenhouse gases or toxins, or both. (Recently, researchers figured out how to coax algae into producing hydrogen, but the process is still experimental.)
Now scientists have pulled a new trick from their sleeve: an experimental system that uses solar cells to split water into hydrogen and oxygen. I’m not going to pretend that I really know what they’re talking about on a technical level. All I care about is the promise inherent in the new research: a day when the power of the sun could be harnessed on our rooftops to cheaply and cleanly create 100% pollution-free energy for use in our own basement fuel cells, which would provide electricity and heat renewably and, yes, even perfectly.
The technology essentially mimics photosynthesis and needs to be refined to reach efficiency levels that would produce useable amounts of hydrogen, but it’s an important first step with lots of potential. The best thing about the idea is what it gives us hope that we human beings are clever enough and wise enough to do what has to be done. Anyone who says that things have to be the way they are simply doesn’t have any imagination.