Gevo Inc. has begun the process of bringing its wholly owned, dairy manure-based renewable natural gas (RNG) project online. The northwest Iowa project, known as Gevo NW Iowa RNG LLC (NW Iowa RNG), is supplied by three dairy farms involving more than 20,000 milking cows and is expected to produce approximately 355,000 MMBtu of RNG per year.
Because dairy manure left in lagoons and used as fertilizer releases high levels of methane to the atmosphere, there is an opportunity to capture that methane as biogas and refine it to be used as RNG. According to Gevo, doing so has no impact on the fertilizer and nutrients available, yet creates more options to sustainably manage fertilizers for sustainable farming practices.
After the methane is extracted from the processed manure, the remaining solids will be returned to the farmers as soil nutrients for use as fertilizer. This will allow the farmers to reduce their raw manure application, which will improve odor, water quality, and nutrient management practices.