I love it when I see stories about new hydrogen fueled cars that will emit nothing but water. With all the focus these past few years on biofuels and more recently electric vehicles we don’t see as many of these stories, but I saw this one today, “Hydrogen cars gaining traction in the marketplace“.
Even better is this one from that energy mecca of San Francisco on Dec 1st, “Era of hydrogen fuel cell cars begins next year.” I love that one because you could just repost it every year about this time and it would still work.
What these stories are really about is using fuel cells to generate electricity to drive the car. So that I get. I wrote a story about the progress of electric cars that highlights that we are indeed heading slowly but surely in that direction overall, at least for light autos. So if that is the case, then why not use hydrogen fuel cells to make that electricity?
Well has anyone seen a hydrogen well around anywhere? Oh, yeah I know we’ll just crack water like we did in high school science class and generate the hydrogen that way. What’s not to like, we have lots of water, just fire up the…wait what exactly do we use to crack that water into hydrogen and oxygen? You guessed it electricity. How do we make that electricity, well lots of ways, but the point is we sure don’t have a ready source of free hydrogen just laying around to use. So consuming electricity to make hydrogen only to then run it back through a fuel cell to then make electricity seems pretty damn silly once folks understand that is what is happening.
So no hydrogen is not a source of energy here on planet earth. It can be a carrier of energy in the form of chemical potential energy that is released when we combine it with Oxygen to make water. Yes if we do that in a fuel cell, you can create direct electric current that is indeed perfectly good electricity.
The little problem is that using hydrogen as an energy carrier is about 10% as efficient in terms of space and density as using gasoline as the carrier. What is even better is that to get at that wonderful inefficiency we’d need to invest in entirely new infrastructure. California plans to spend $20 million a year on new hydrogen fueling stations for the next 10 years, and expects that they will then have a whopping 100 stations open. Now that’s bang for your buck.
All of that misses the point anyway. That point is that we make the vast majority of our hydrogen today from natural gas. Yep, goes back to fossil fuel anyway, so if you are going to use a fossil fuel, then just use it in the most efficient way possible. Don’t add in 10 extra steps that eat up tons of energy along the way just so some movie star can feel good about driving a car that emits only water.
Thinking On Energy 