Hydrogen Fuel Production Takes Another Step Forward

Researchers at Penn State University have developed a method using bacteria and common materials to generate hydrogen at previously unachievable levels according to a press release from the National Science Foundation. This work could pave the way for an efficient and net-energy-positive means of producing hydrogen as a fuel source.

"We achieved the highest hydrogen yields ever obtained with this approach from different sources of organic matter, such as yields of 91 percent using vinegar (acetic acid) and 68 percent using cellulose," said principal investigator Bruce Logan, a professor of environmental engineering at Penn State.

Logan's method has nearly double the net-energy impact as producing hydrogen through electrolysis, which breaks down water into its two components, hydrogen and oxygen.

The team at Penn State developed a technology called microbial electrolysis cells (MECs) as part of the federal government's alternative fuels initiative funded in part by the National Science Foundation. The MECs take organic compounds, such as vinegar, alcohol or materials containing cellulose, combine them with hydrogen producing bacteria, and give them a very small jolt of electricity. The microbes break down the material into hydrogen, water and carbon dioxide, and theoretically could be fueled by the contents of a common salad bar.

While the team achieved heretofore unachievable levels of efficiency, the process still remains relatively slow, taking 24 hours to produce 1.23 cubic meters of hydrogen for every cubic meter of the MEC. Another alternative fuel production method under commercial development, thermal depolymerization, which takes the waste stream from sewage, only takes two hours to produce take 1400 gallons of waste and convert it into roughly 294 gallons of light-weight oil and 56 gallons of methane.

Logan and his team are now working on speeding up the process, to achieve production levels high enough to make the process commercially viable.

Bruce Hamilton, NSF director of the environmental sustainability program says "Bruce Logan is a clear leader in this area of research on sustainable energy," Hamilton oversees the grant that funds Logan's work.

Logan thinks hydrogen-methane fueled vehicles may be just around the corner. "We drive a lot of vehicles on natural gas already. Natural gas is essentially methane," says Logan in a press release from Penn State. "Methane burns fairly cleanly, but if we add hydrogen, it burns even more cleanly and works fine in existing natural gas combustion vehicles."

Logan and principal author Shaoan Cheng announced their findings online version of Proceedings of the National Academy of Sciences on November 12.