Cows stand in a field.

Image: Shutterstock

As it turns out, farm waste serves more of a purpose than simply stinking up neighborhoods around the world. Sometime soon, a United Airlines flight will leave from Los Angeles for San Francisco using fuel made from farm waste and animal fat.

Lots of things can be used as alternative forms of fuel, like electricity or biodiesel, but organic waste (read: pig and cow poop) is high in methane, a greenhouse gas, which both has the power to, well, power a lot of things—and its potency can be problematic if not attended to. Using farm waste as fuel is a win-win situation for farmers, who can both get rid of the smelly stuff while making a profit on it, according to NPR News. It’s also a win for airlines as they look for ways to reduce their fuel expenses.

Beef tallow, or fat, is also being converted into an alternative energy source. United Airlines has purchased 15 million gallons of the fuel and has invested $30 million in Fulcrum BioEnergy, Inc., a company that coverts household waste into fuel. FedEx, UPS, Southwest Airlines, and a score of other businesses have also bought considerable amounts of alternative fuels. Alaska Airlines aims to have at least one of its airports using only waste fuel by 2020.

The cost of waste-based fuel is less than the cost of regular jet fuel at about $2 a gallon currently, though should the industry grow, that number is expected to drop even lower.

Reducing the number of greenhouse gases is good for everyone, and using alternative fuels could reduce the cost of jet fuel for airlines—which might, we hope, lower the cost of flight tickets and other expenses. The entire process of alternative-fuel creation, delivery, and support have not yet been completely ironed out in cost-effective ways, particularly as each region is home to different kinds of livestock that live on different kinds of feed. But because airlines can’t become electric as cars have, there is a lot of hope—and need—for sustainable, renewable energies to become the way of the future flight.