Just a quick note: the current issue of Science reports (non-free subscription required) that researchers at the University of Minnesota have developed a system for converting ethanol into hydrogen cheaply and efficiently. As most techniques for producing hydrogen for fuel cells use fossil fuels as source material, this will be a significant step away from non-renewable energy resources. The press release at the UMN website gives details.
When coupled with a hydrogen fuel cell, the unit - small enough to hold in your hand - could generate one kilowatt of power, almost enough to supply an average home, the researchers said. The technology is poised to remove the major stumbling block to the hydrogen economy: no free hydrogen exists, except what is made at high cost from fossil fuels.
The researchers see an early use for their invention in remote areas, where the installation of new power lines is not feasible. People could buy ethanol and use it to power small hydrogen fuel cells in their basements. The process could also be extended to biodiesel fuels, the researchers said.
Ethanol is easy to transport and relatively nontoxic. It is already being produced from corn and used in car engines. But if it were used instead to produce hydrogen for a fuel cell, the whole process would be nearly three times as efficient. That is, a bushel of corn would yield three times as much power if its energy were channeled into hydrogen fuel cells rather than burned along with gasoline.
We can potentially capture 50 percent of the energy stored in sugar [in corn], whereas converting the sugar to ethanol and burning the ethanol in a car would harvest only 20 percent of the energy in sugar, said Schmidt. Ethanol in car engines is burned with 20 percent efficiency, but if you used ethanol to make hydrogen for a fuel cell, you would get 60 percent efficiency.
Fuel cells for use in transportation aren't that efficient though - actually hardly better than internal combustion engines, particularly those used at optimal revs in hybrid engines.
However, their point about not needing to remove the water from the ethanol is an interesting one. Right now ethanol made from corn and used in transportation barely returns more energy than the fossil fuels expended in growing the corn and processing it to ethanol in the first place. If they can greatly reduce energy use in processing this way, it's a good step.
"Right now ethanol made from corn and used in transportation barely returns more energy than the fossil fuels expended in growing the corn and processing it to ethanol in the first place."
Granted, it feels like the utopian numbers quoted need an injection of reality from a few other sides. But what about when we factor back in the cost, both in actual processing costs, and in extended environmental costs, of the fossil fuel usage this could replace? There must be some gains there. Especially if the technology could be put to immediate use to replace some fossil fuel usage in the manufacture and transport of the ethanol.
One small example that just popped into my head - just imagine the plusses from having self powering underground pipelines of ethanol instead of the fossil fuel pipelines we currently have criss-crossing the nation...and this is just one small piece of the equation.