Shots Across The Bow

New Hydrogen production methods

SK Bubba links to a couple of experiments dealing with new ways to generate H2. The hope is to find an inexpensive way to generate H2, making fuel cells practical.

The first link is to ORNL's experiment in producing H2 by photosynthesis. They say that they are producing close to the theoretical maximum of 12 moles H2 for every mole of sugar processed. Unfortunately, the article doesn't give us relevant info like time and area required, but we'll go with what we have.

A mole of sugar weighs approximately .4 lbs and a mole of H2 weighs approximately .004 lbs, so we have a 8:1 relationship. So 8 kilos of sugar will be converted to 1 kilo of H2.

The energy value of a kilo of H2 is about 33.3kWh, and a fuel cell will utilize about 60% of that, or 20kWh. 20 kWatts is equivalent to approximately 27 horsepower, so assuming a car runs with 150 horsepower, the energy from 100 kilos of sugar will run the average car for about 10 minutes. 8 kilos of sugar is about 18 pounds for those of us who hate the metric system.

That's a lot of sugar.

In his second reference, the process uses specially designed membranes to catalyze the splitting of water into H2 and O2. reading the patent claim, I discovered that the process takes place at around 1000 degrees centigrade, or 1832 degrees F. That's going to take some significant energy to maintain. While it may make it less inefficient to liberate the hydrogen, it still doesn't get us past the laws of thermodynamics.

No matter how many clever ways we try to get around it, you can't get out more than you put in. But what fuel cells and hydrogen technology might do for us is lower the back end costs, pollution, environmental damage, etc to the point where the additional front end costs are compensated for. Looked at from that perspective, every little bit helps.

Posted by Rich at February 27, 2003 4:03 PM | TrackBack