In Cleveland, the Indians began using the process last year, following the Browns, who started in 2013, and a casino has recently joined the effort.

Well before the start of a Cleveland Indians game at Progressive Field, as players warmed up on the jewel-green field, it was business as usual in the garage behind left field for C.L. Gholston, a dishwasher.

He had wheeled down gray bins full of kitchen scraps—pineapple and melon rinds, carrot shavings and tomato ends—that were all part of the mix he fed into a contraption he calls the “energy machine.”

The machine grinds all types of food waste, including skin, fat, flesh and bone, into a slurry that is later transformed into energy and fertilizer at a plant operated by the renewable energy company Quasar.