Last year we published a post on a small Pennsylvania company, NanoLogix, that had patented a means of "Hydrogen Synthesis from Bacteria and Waste Heat Inputs," a feat remarkable for its reliance on toxin-producing Clostridium bacteria.
From the following year, one marked by much punditory and investor fuss over cellulosic ethanol, plenty of hoopla over algal biodiesel, and a stream of overt criticism of hydrogen-based fuel cells, principally directed at the 'inefficiency of H2 production.' we emerged with a gut feel that something new would change everything. It might have.
At the bench scale, a report on bio-hydrogen work by a team from Pennsylvania's Penn State University seems poised to eclipse last year's fuss, as this startling announcement demonstrates: "In new table-top reactor, bacteria from wastewater produce abundant, clean hydrogen from cellulose, or even vinegar, and a little electricity."
Bruce Logan and colleagues at Penn State University had already shown success at using microbes to produce electricity. Now, using starter material that could theoretically be sourced from a salad bar, the researchers have coaxed those same microbes to generate hydrogen.
By tweaking their design, improving conditions for the bacteria, and adding a small jolt of electricity, they increased the hydrogen yield to a new record for this type of system....
"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 Logan.
Even with the small amount of electricity applied, the hydrogen ultimately provides more energy as a fuel than the electricity needed to drive the reactor. Incorporating all energy inputs and outputs, the overall efficiency of the vinegar-fueled system is better than 80 percent, far better than the efficiency for generation of the leading alternative fuel, ethanol
Pennsylvania is the mother of all coal states. Wouldn't it be a wonder if the seminal breakthrough which one day makes the H2 fuel cell a vital transportation technology, was originating, just now, in the center of Penn's historically coal-dusted woods? Almost makes a writer want to believe in the Gaia hypothesis circumscribing the human intellect.
The bio-hydrogen work appears to have no direct involvement with patent holders of existing fuel cell technology, and no visible support from the US Department of Energy. Quite interesting, is the stated support of the work by Air Products and Chemicals, Inc, yet another Pennsylvania based company that widely distributes industrial gases, including hydrogen, and has a published commitment to sustainable development.
This Penn State press release on the project adds further efficiency comparisons:
"This process produces 288 percent more energy in hydrogen than the electrical energy that is added to the process," says Logan.
Water hydrolysis, a standard method for producing hydrogen, is only 50 to 70 percent efficient. Even if the microbial electrolysis cell process is set up to bleed off some of the hydrogen to produce the added energy boost needed to sustain hydrogen production, the process still creates 144 percent more available energy than the electrical energy used to produce it.
For those who think that a hydrogen economy is far in the future, Logan suggests that hydrogen produced from cellulose and other renewable organic materials could be blended with natural gas for use in natural gas vehicles.
"We drive a lot of vehicles on natural gas already. Natural gas is essentially methane," says Logan. "Methane burns fairly cleanly, but if we add hydrogen, it burns even more cleanly and works fine in existing natural gas combustion vehicles."
The range of efficiencies of hydrogen production based on electrical energy and energy in a variety of organic substances is between 63 and 82 percent. Both lactic acid and acetic acid achieve 82 percent, while un-pretreated cellulose is 63 percent efficient. Glucose is 64 percent efficient.
Another potential use for microbial-electrolysis-cell produced hydrogen is in fertilizer manufacture. Currently fertilizer is produced in large factories and trucked to farms. With microbial electrolysis cells, very large farms or farm cooperatives could produce hydrogen from wood chips and then through a common process, use the nitrogen in the air to produce ammonia or nitric acid. Both of these are used directly as fertilizer or the ammonia could be used to make ammonium nitrate, sulfate or phosphate
Fair disclosure: a bit of bias is included, as this writer lives in Pennsylvania, USA and does think that hydrogen has an important future as a transportation fuel. Plus, I just want to be able to tell my grandkids that my car was one of the first to run on vinegar.