Today's topic is something that has been bothering me for a while. It has to do with hydrogen fuel cells, touted by many as the solution to our energy problems, as well as to global warming.
There are many reasons why hydrogen is not the salvation that many claim. First and foremost, hydrogen is not a fuel source. It is a storage method for energy derived from other methods.
So, in order to get the equivalent energy of a gallon of gasoline, you have to burn the equivalent of significantly more than a gallon of gasoline, with all of the pollution, carbon dioxide, petroleum availability, and other concerns. Of course, you can also burn coal, use nuclear energy, or use large (probably impractical) amounts of solar or wind energy.
Creating vast amounts of hydrogen also takes even vaster amounts of water. Hydrogen is also hard to store and transport. Even liquid hydrogen, which requires additional energy to keep cold, takes up four times the volume as gasoline to generate the same amount of energy.
But the promise of so-called pollution-free energy is tempting. Ignore for a moment the amount of pollution (including the dreaded carbon dioxide) put into the atmosphere just to create and transport the hydrogen required to fuel something like an automobile. The only byproducts created when you burn hydrogen to create energy are heat and water vapor.
Here's what bothers me. A century ago we traded in our smelly and manure-generating horsedrawn carriages for gasoline-powered automobiles. And now, a century later, we are discovering that cars not only smell bad and generate pollution, they are part of the cause of a huge change to our planet's climate. Pretty heavy stuff for our grandparents to leave us.
How do we know that our solution to gasoline-powered mobility isn't going to leave an equivalent legacy for our grandchildren?
A recent study
discovered that the amount of rainfall in Phoenix has increased by 12-14% in recent years, due to human activities. However, anybody who has lived in the southwest US for a while can tell you that things are hotter and more humid now than they were before all the people came. Human activities have increased the amount of water vapor in the air in arid cities.
What would happen if you had hundreds of millions of cars spewing water vapor into the air? Would that cause another uptick in humidity in the arid and formerly arid regions? Will we be creating a new source of local climate change?
Now, think about global warming and the greenhouse effect. The focus in the media has been mostly on carbon dioxide. CO2
is a potent greenhouse gas, we are pumping huge amounts into the air, and temperatures on our planet are rising.
However, water vapor is also a greenhouse gas. Most of the public focus has been on CO2
, since that is the biggest change we are forcing into the system. In the climate models, as I understand it, H2
O is not considered a driving factor. On the average over the entire planet, if more water is evaporated into the air, more precipitation will happen, and the amount of H2
O will remain constant.
But what happens if we create a new, huge source of water vapor directly into the air? What if we do that everywhere, including the arid and semi-arid parts of the country and world? If we increase local humidity in a large enough percentage of the planet, won't that have a measurable impact on the average global levels of water vapor?
Hydrogen fuel cells would then be a driver for both local climate change and global climate change.
Of course, when things heat up, whether because of increased CO2
or increased H2
O, the air will be able to hold more H2
O, which will then further drive global warming.
Because of the many huge hurdles to overcome, it will be a long time before hydrogen fuel cells will be a feasible replacement for any significant portion of our current energy consumption, if ever. Let's hope that before we jump on a new technology bandwagon as the solution to the problems of the current system we take a long hard look at the consequences.
Labels: climate, energy, environment, science, transportation