May 19, 2007
A "Revolution" in Renewable Energy? Maybe Not.
Snake oil or salvation? Via MSNBC:
A Purdue University engineer and National Medal of Technology winner says he's ready and able to start a revolution in clean energy.Wow. It sounds almost too good to be true. Yet another new process for generating energy from water. With all the water on this planet, our energy problems should be behind us in no time. We can finally tell Hugo Chavez and those damned Saudis to kiss our asses!!! Sayonara, suckers!!!
Professor Jerry Woodall and students have invented a way to use an aluminum alloy to extract hydrogen from water — a process that he thinks could replace gasoline as well as its pollutants and emissions tied to global warming.
But Woodall says there's one big hitch: "Egos" at the U.S. Department of Energy, a key funding source for energy research, "are holding up the revolution."
...or maybe not. Find out why below the fold.
It seems like we're seeing stories like this on a fairly regular basis, usually written by enthusiastic, but often technologically-challenged, journalists who are willing to believe almost anything a researcher tells them. I have no reason to doubt that the process described in the article works to generate hydrogen from water. It probably does, but this process isn't a revolution, or even an "invention."
Elemental metals like oxygen, and aluminum likes oxygen a lot. Aluminum's not unique in this respect. Drop some metallic sodium in water sometime and see what happens. (I strongly recommend you watch from a safe distance.) You can mix other things with water to make fuel. You can generate acetylene, for example, by mixing water and calcium carbide. In other words, the idea of generating hydrogen by reacting water with a metal or other chemical is far from revolutionary, controversial or even new. This would've been ground-breaking stuff in 1750. In 2007? Not so much.
The article doesn't mention it, but Prof. Woodall filed for his patent on this almost 27 years ago and the patent has long-since expired. (It's patent number 4,358,291 if you want to check it out.) Even though the chemistry here is likely sound, it's far from novel, and there are some troublesome facts that didn't make it into this article.
Generating hydrogen fuel from water and metal sounds like a really good idea until you realize some troublesome facts, starting with...
TROUBLESOME FACT # 1 : By mass, water is mostly oxygen. There's not much hydrogen in water.In fact, in NINE pounds of water, there's only ONE pound of hydrogen. Since a hydrogen-burning engine generates water as its waste product, this isn't as big a problem as it may first appear, as the waste water can likely be recycled.
The other troublesome facts are, however, more "troublesome."
The article touches on the fact that this process consumes aluminum, but it fails to go into any detail as to how much. The article refers to the aluminum almost as if it were just some type of catalyst or something, but in fact this process consumes very large quantities of aluminum. I noted above that it takes 9 pounds of water to get 1 pound of hydrogen. This brings us to...
TROUBLESOME FACT # 2 : The process of reacting aluminum with water consumes roughly NINE pounds of water and EIGHT pounds of aluminum for every ONE pound of hydrogen it generates.Now, 16 pounds of solid waste product may not seem like a big deal until you realize that the 1 pound of hydrogen fuel you've just generated is the energy equivalent of less than ONE HALF GALLON of gasoline. That's where the big, 350-lb. chunk of aluminum alloy comes in. The article mentions that there's a 350-lb. chunk of aluminum alloy added to the vehicle and that some aluminum is consumed by the process, but the article fails to elaborate...
TROUBLESOME FACT # 3 : The process of reacting aluminum with water generates roughly SIXTEEN pounds of aluminum oxide waste for every ONE pound of hydrogen it generates.
TROUBLESOME FACT # 4: At an average level of automotive efficiency, the 350-lb. chunk of aluminum will be consumed every few hundred miles.This is an important fact that was left out of the article. Another thing...
TROUBLESOME FACT # 5: Given the same assumption on efficiency, the 350-lb. chunk of aluminum will be converted into a 700-pound chunk of aluminum oxide which will, again, have to be disposed of every few hundred miles.
Bottom line : it's not that water can't be reacted with metals to generate hydrogen. It certainly can, and scientists have known of this phenomenon for centuries. The problem is that "filling up" your car for this would morph from a simple matter of adding a liquid fluid (gasoline) to a tank into a process much closer to removing the old fuel tank and putting in a new one. And this would have to be done every time you "fill up." This just doesn't seem to me like something most drivers would be willing put up with unless the product was virtually free.
A revolution? Not quite.