Fuel Cell Mower

Now, what about making the lawnmower a vegetarian: a machine that processes its own grass clippings to make a biofuel that makes its engine go?

Like a goat, for instance?

This is a spinoff of a previous topic on the controllable fuel cell a few days back (I don't know why it is being repeated in an inferior form):

The original article link that describes the fuel cell operation in much better detail. It essentially controls the water level in the cell which varies the amount of exposed reactive area.

http://www.whatsnextnetwork.com/technology/index.php/2007/01/16/breakthrough_design_in_fuel_cell_technol

My previous post:

"An interesting twist, but other than making a $5000 lawnmower with sluggish performance and a need to be kept above freezing temperatures closer to reality I see little practical use anytime soon in outdoor mobile use. In a stationary indoor application however, it could be useful. Using changes in the water level to control output does not seem viable in a fuel cell subject to various acceleration forces or in a climate where freezing could occur.

The major obstacles are the very high initial cost, and relatively short lifetimes, of fuel cells in general. The H2 is pure, but the O2 in all consumer applications is from the ambient air, and the other gases and pollutants in the air cause "fouling" of the fuel cell over time resulting in a continual degradation of its output.

These are problems that will likely be solved over time in a way that might make the fuel cell economically competitive but there are many other technologies in the pipeline that may get there before the fuel cell as we presently define it. Biotechnology, nanotechnology, and/or matrices of micro or nano-machines are but some of the emerging technologies that may convert chemical energy to mechanical energy in a more cost effective and durable manner. And of course, recent history tells us not to rule out improvements or new variations of existing technology (IC engines in particular). For lawnmowers, a liquid fueled (not necessarily gasoline) IC engine with pollution controls or improved rechargeable battery powered models are infinitely more likely in the foreseeable future.

In any case, a fuel cell powered lawnmower sounds like something an "academic" would propose!"