New Method Creates Cheap, Clean Hydrogen Gas

Researchers at Penn State University have developed a method of producing hydrogen gas from almost any biodegradable organic substance, from grass clippings to wastewater, potentially providing an abundant source of this clean-burning fuel.

Hydrogen is touted as a virtually limitless source of clean energy. Public transport systems worldwide are moving toward hydrogen-powered engines as an alternative to petrol engines, because they burn hydrogen to produce only water. But the problem is that most hydrogen available today is produced by expensive processes that require the burning of polluting fossil fuels, such as natural gas - a problem the new method seems to solve because it uses existing technology and can be put to use immediately.

The method used by engineers at Pennsylvania State University 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.

A microbial electrolysis cell (MEC) shown with the power source (upper right) and hydrogen monitoring device (upper left) used to produce hydrogen using bacteria.

Using acetic acid, a common waste product of industrial fermentation, the authors' reactor generated hydrogen gas at efficiencies up to 99% of the theoretical maximum yield. "This process produces 288 percent more energy in hydrogen than the electrical energy that is added to the process," says Prof Logan one of the authors of the study.

"There are substantial infrastructure issues to be addressed in using hydrogen gas, but the environmental and energy-conversion efficiency benefits for hydrogen as a transportation fuel makes it worth addressing and solving these issues," conclude the authors.

[source: Penn State University]