United Airlines invested $30 million in alternative energy developer Fulcrum BioEnergy,

the carrier announced Tuesday. United also negotiated an agreement to purchase at least 90 million gallons of fuel from Fulcrum for 10 years or more “at a cost that is competitive with conventional jet fuel,” according to United. Fulcrum and United agreed to develop as many as five projects near United hubs that could produce as many as 180 million gallons per year. The energy company's technology converts household waste to jet fuel, and it expects its first plant will begin operations in the third quarter of 2017.