Posts Tagged ONR

Bacteria and Fuel Cells

Posted by on Tuesday, 1 June, 2010

Fuel Cells are popular because they present the potential to power cars, airplanes, and other machines without burning coal, oil, or natural gas without using petroleum based energy. It’s necessary to remind people that fuel cells are a type of battery, they don’t actually generate renewable energy so they must receive power from another source. Charging a fuel cell or another battery from a wall outlet might actually cause more pollution depending on where the power is generated. The main advantage of fuel cells is that they can store power which is generated by many different types of sources.

Conventional fuel cells operate with a reaction that uses up elemental hydrogen. Although hydrogen in its pure form is present in outer space, it is extremely rare and unlikely to find any elemental hydrogen on the Earth. The hydrogen must be reduced from another source such as water before it can be used in a battery, which uses energy. As with other types of machinery, the natural environment provides some models of useful systems that have evolved over periods of millions of years. Since animals and plants that are not efficient die out, these systems are much more efficient than previous competitors and even some machines that humans have designed. According to the Advanced Research Projects Agency, a bacteria based fuel cell can be ten times as efficient as a hydrogen based fuel cell. Bacterial fuel cells also are not reliant on elemental hydrogen, since it rarely exists on Earth. They can use other materials, even waste products like pig manure and sewage, according to Science Daily.

Also known as microbial fuel cells, since microbes include bacteria, the effectiveness of these devices is already proven. Researchers at Penn State demonstrate that a bacteria based fuel cell can convert waste from a toilet into a reliable source of energy. Although this early demonstration project in 2004 did not produce a large amount of energy, it demonstrates that the concept is possible, and will produce a large amount of energy when scaled up. One goal of ARPA-E is to provide federal grants to companies who submit proposals which show that they can scale up this process and produce large amounts of energy, as part of ARPA-E’s electrofuels grant program. The naval research center, ONR, demonstrated that bacteria found in wastewater and mud are capable of generating energy as part of a microbial fuel cell.