Bulls, babies and bacteria

When it comes to energy, we’re usually speaking in the figurative when we talk about “clean” energy, or “dirty” power. But for some alternative fuel sources, those labels become far more literal. After all, while holding a chunk of coal might leave you brushing off some carbon residue, a fistful of manure is definitely going to require a thorough wash afterward.

Nobody’s saying we shouldn’t make better use of the waste we produce. Alternative fuel sources like landfill gas and the methane produced from manure are proving that conservation makes economic, as well as environmental sense. Years ago, for instance, disposing of fryer grease was a chore that franchise restaurants had to pay others to do for them. Now, the grease is not only disposed of, it’s become so valuable that profiteering “pirates” are actively stealing it from fast food grease traps.

Still, it’s a messy business turning dung into dollars.

There’s a distinct correlation between the “ick” factor of a waste product and its eventual use as a fuel source. And it goes beyond the fact that people are probably more inclined to handle something as appealing as corn over something as repulsive as trash heaps.

Methane, one of the six primary greenhouse gases identified under the Kyoto Protocol, derives from fermenting organic materials, which means that while the gas itself may be odourless, its companions rarely are. Diapers, for example, produce methane (in addition to offering the recyclable materials of the diaper itself), and the drive toward manure as a fuel source comes with growing recognition of the greenhouse gas emissions from industrial-scale feedlots. Whether they’re babies or bulls, the result is the same — metric tonnes worth of poop that’s sending greenhouse gases to high heaven.

And the stinky correlation isn’t confined to methane. Researchers in the UK recently unveiled a process that turns food waste into hydrogen, one of the most promising alternative fuel sources. In a bioreactor, “biohydrogen” is created by the same bacteria whose fermentative processes turn waste materials into the smelly substances we otherwise avoid. In the absence of oxygen, they create hydrogen, which in turn can be used to produce an emission-free reaction in a hydrogen fuel cell. Not bad for table scraps.

Whether they release methane or hydrogen, waste products carry more than the smells that keep most of us at bay. Beyond the backyard composting that keeps our garden healthy, recycling waste is reaching an industrial scale that will change the way we generate power, “clean” or otherwise. So, as sources of alternative power become increasingly appealing in the face of rising fuel prices, holding our noses will just become that much easier.