[ExI] Novel technique for cheap and abundant hydrogen

[Damien Broderick]

http://www.cosmosmagazine.com/node/1697


Novel technique for cheap and abundant hydrogen

Tuesday, 13 November 2007
Agençe France-Presse

CHICAGO: A new method of producing hydrogen gas 
from biodegradable organic material has been 
developed, potentially providing an abundant source of clean-burning fuel.

The technology offers a way to cheaply and 
efficiently generate hydrogen from readily 
available and renewable biomass such as cellulose 
or glucose, and could be used for powering 
vehicles, making fertiliser and treating drinking water.

Public transport systems

Numerous public transportation systems are moving 
toward hydrogen-powered engines as an alternative 
to gasoline, but most hydrogen today is generated 
from non-renewable fossil fuels such as natural gas.

The new method developed by engineers at 
Pennsylvania State University in University Park, 
U.S., combines electron-generating bacteria and a 
small electrical charge in a microbial fuel cell to produce hydrogen gas.

Microbial fuel cells work through the action of 
bacteria, which can pass electrons to an anode. 
The electrons flow from the anode through a wire 
to the cathode producing an electric current. In 
the process, the bacteria consume organic matter 
in the biomass material. An external jolt of 
electricity helps generate hydrogen gas at the cathode.

In the past, the process, which is known as 
electrohydrogenesis, has had poor efficiency 
rates and low hydrogen yields. But environmental 
engineers Shaoan Cheng and Bruce Logan were able 
to get around these problems by chemically modifying elements of the reactor.

Economically viable now

Their study appears in the U.S. Proceedings of 
the National Academy of Sciences.

In laboratory experiments, their reactor 
generated hydrogen gas at nearly 99 per cent of 
the theoretical maximum yield using aetic acid, a 
common dead-end product of glucose fermentation.

"This process produces 288 per cent more energy 
in hydrogen than the electrical energy that is 
added in the process," said Logan.

The technology is economically viable now, which 
gives hydrogen an edge over another alternative 
biofuel, which is grabbing more headlines. "The 
energy focus is currently on ethanol as a fuel, 
but economical ethanol from cellulose is 10 years 
down the road," said Logan. "First you need to 
break cellulose down to sugars and then bacteria can convert them to ethanol."

One of the immediate applications for this 
technology is to supply the fuel for electric 
fuel cell vehicles – but it could also be used to 
convert wood chips into hydrogen to create fertiliser, said the researchers.