Hydrogen, the most theoretically accessible power carrier in the universe, is being harvested in different ways and on different occasions, using even the most unexpected technologies. As an example, the Napa Wine Company in Oakville found an interesting way of producing hydrogen by using the winery’s own wastewater, using naturally-occurring bacteria and a small amount of electricity to extract hydrogen the organic material they usually throw away,with a generator the size of a refrigerator.
Penn State’s Bruce E. Logan, a passionate hydrogen believer, says: “This is a demonstration to prove we can continuously generate renewable hydrogen and to study the engineering factors affecting the system performance,” said Bruce E. Logan, Kappe professor of environmental engineering. “The hydrogen produced will be vented except for a small amount that will be used in a hydrogen fuel cell.”
The wastewater comes from cleaning equipment, grape disposal, wine making and other processes. The company already has on-site wastewater treatment and recycling and the partially treated water from the microbial electrolysis system will join other water for further treatment and use in irrigation.
“It is nice that Napa Wine Company offered up their winery and facilities to test this new approach,” said Logan. “We chose a winery because it is a natural tourist attraction. People go there all the time to experience wine making and wine, and now they can also see a demonstration of how to make clean hydrogen gas from agricultural wastes.”
Napa already has a demonstration microbial electrolysis plant that will process around 1,000 liters per day. The electrolysis cell consists of two electrodes immersed in liquid (the wastewater). The positive electrode is made of carbon, and the negative electrode of stainless steel. To cut costs, they didn’t use electrodes coated with precious metals like platinum or gold.
The bacterial electrolysis cell works this way: wastewater enters the cell, where the bacteria convert the organic material into electricity. By slightly increasing the voltage that the bacteria produces, hydrogen is produced by normal electrolysis on the negative stainless steel electrode. The demonstration plant is made up of 24 modules, each module having six pairs of electrodes. “The composition of the wastewater will change throughout the year,” said Logan. “Now it is likely to be rather sugary, but later it may shift more toward the remnants of the fermentation process.”
The hydrogen produced this way will be used to partially re-power the electrolysis process, through a hydrogen fuel cell, and the main part of it will be collected and used for the company’s internal needs, that don’t exclude powering their cars.
Please take note that the whole technological chain they have there will also bring a lot of green-minded visitors, so the system’s maintenance will probably come for free.