Hydrogen still has
potential as a fuel

I read with interest your short article on "Browns Gas" in "Ask SILICON CHIP" (September 2008 issue, pages 89-90) and hasten to add that I agree with the majority of your comments.

However, I would like to challenge your comment that the use of hydrogen as a fuel is never likely to come to anything. There is at least one quite promising research project being undertaken within Australia which involves producing hydrogen as a usable and practical fuel, although the approach is a little unconventional.

There is a reasonably well-known industrial process which uses waste "high grade" (ie, around 800°C) heat to convert methane (CH₄) to H₂ and CO in a catalytic process. The resultant blend of hydrogen and carbon monoxide is often referred to as Syngas. The principle is that the otherwise wasted heat energy is stored in the molecular structure of the gas so that the resultant gas has a higher (up to 30%) calorific content than the original.

CSIRO have a test plant running at their solar research facility in Newcastle where they use heat generated in a solar tower rather than using waste heat. Natural gas is pumped through a catalyst at the top of the solar tower and H₂ & CO comes out the other side (keep in mind that CO is combustible).

The initial reaction to this concept is that it is cheating. All they are doing is taking a non-renewable resource and modifying it! Thinking it through a bit further though, how hard is it to store solar energy and how much harder to store it in a medium that can be easily transported and used in multiple applications?

The point is that the energy content of the methane is less than the energy content of the synthesised hydrogen/carbon monoxide mixture. The difference is the heat that has been added. If that heat is from solar energy, it is effectively free. If it is from waste heat from industrial processes again it is effectively free because it would otherwise just be heating up the atmosphere. Thus, energy has been stored that is otherwise difficult to capture.

My understanding is that CSIRO now have significant Federal and state government funding for a pilot/research plant to be built in Queensland. Further details can be found at http://www.det.csiro.au/science/r_h/nsec.htm

While I accept that this is a long way from being developed into a commercial proposition, it does appear that there is enough happening out there to stop us writing off hydrogen as a fuel just yet.