Coffee is one of the most wasteful consumer products. Few people realize that harvesting, processing, roasting and brewing coffee discards an estimated 99.7 percent of the biomass, only 0.2 percent is used to make you enjoy your cup of coffee. Millions of tons of agricultural waste are left to rot, generating millions of tons of methane gas, contributing to the climate change. And then there are the leftover coffee grounds. But here’s some good news: Scientists have found an efficient way to make biofuel from used coffee grounds.