Gevo expects to generate renewable natural gas, or RNG, by collecting manure from dairy farms. This concept fits in with our philosophy of addition by subtraction: We simultaneously seek to reduce greenhouse gas emissions (GHGs) as we figure out ways to generate usable renewable energy from the process.
According to Our World In Data, food production accounts for 25 to 35 percent of global GHGs, with more than 7 billion tons of carbon dioxide of that amount attributed to livestock and fish farms. Livestock contributes emissions to this measurement in a few different ways:
- Enteric fermentation is gas produced by microbes in the digestive system of livestock animals, chiefly methane. It is emitted through belching and flatulence, and this usually increases when the animals are fed starchy food.
- Manure management contributes to GHGs. As manure is left to decompose, it releases greenhouse gases, including methane.
- Management of pastureland is also a factor, as the ground emits carbon dioxide.