The average dairy cow produces around 40,000 pounds of manure a year, most of which doesn’t just disappear into thin air. As a cow pie decomposes, some of that solid waste does become a gas, the most notorious of which is methane. Even though you can’t see all that CH4, it makes a big difference to the world since it traps 23 times more heat in the atmosphere than carbon dioxide. Fortunately, methane doesn’t need to simply waft away, and farms are now using their cow poop to power everything from buildings to the very feed trucks that carry food to cows in the first place.
Prepping poop for generating power
Unfortunately, you can’t just scoop some poop into a gas tank and be on your way. Cow poop is made of a variety of materials which need to be separated so they can be used more efficiently, not totally unlike the refinement processes for crude oil. To make the most of their manure, farms have to invest in a huge container called a digester. The digester helps maintain an optimal temperature for poop to break down, and conveniently contains the unpleasant “barnyard aromas” at the same time. The products of digestion are fibrous materials that can be used as cow bedding or other products, potent liquid fertilizer, and assorted “biogases,” including methane.
Methane burns easily, which is why it’s the primary component of natural gas. Burned in combustion generator, plenty of electricity can be harvested to power farms, trucks, and even surrounding communities. Again, the methane doesn’t simply vanish into thin air though, and burning methane does create carbon dioxide as one of it’s by-products. Still, since carbon dioxide isn’t as potent a greenhouse gas as methane, most people consider this a win. It doesn’t hurt if farms can be more self-sustaining either.
The amount of power than can be generated from reused cow poop is significant enough that many farms are looking to expand their capacity. Farmers that have made the investment to set up one digester are often interested in setting up a second. The Straus Family Creamery in California took a different approach, and invested in a lengthy retrofitting project with their International Harvester feed truck. After eight years of work, they converted the diesel truck into a zero-emissions electric vehicle so that it could be powered by their poop-fueled generator. Apparently the creamery feels their cows’ poop can provide even more, and they plan to power a delivery truck with methane-produced electricity in the near future.
Source: Poop-Powered Electric Feed Truck Debuts at Northern California Creamery by Tiffany Camhi, The California Report