German electricity plant runs on corn waste
Non-edible plant materials like corn husks and stalks produce biogas more efficiently than cereal crops.
German scientists at the Fraunhofer Institute for Ceramic Technologies and Systems have developed an electricity plant that produces its biogas, a form of biofuel, from non-edible plant waste.
The Dresden, Germany, plant produces biogas from corn waste like husks and stalks, notably not cobs. Like other bioenergy plants, the biogas is then converted into electricity at the plant.
Because this electricity plant does not use any edible crop sources, the system, if scaled up for wider use, would not interfere with world food supplies, according to a statement from the group.
Not only is the plant agro-friendly because it avoids using feedstocks, the scientists have also come up with a quicker method for fermenting the ingredients.
The biomass used at the Dresden plant are decomposed in about 30 days compared to the typical 80 days it takes to ferment feedstock biomass.
"Corn stalks contain cellulose which cannot be directly fermented. But in our plant, the cellulose is broken down by enzymes before the silage ferments," Michael Stelter, head of the research group, said in a statement.
To produce the electricity from the biogas, the plant uses a high-temperature fuel cell with a combined electrical and thermal efficiency of about 85 percent. That, too, is more efficient, according to the scientists who contend that the average combustion engine only has an efficiency of about 38 percent.
As of now, the plant is only built to produce about 1.5 kilowatts of electricity, barely enough to supply one home. Now that the system works, the group plans to step it up to two kilowatts.