Several months ago, I learned of a unique form of truly renewable energy production in Wisconsin – anaerobic biodigesters. Biodigesters have been around for decades, predominantly in Europe, but their potential has yet to be fully realized here in the United States.
A biodigester is a synthetic, 100 degree cow stomach in which manure is broken down by bacteria in the absence of oxygen, yielding three beneficial products: biogas, bio-solids and liquid fertilizer. Methane biogas, produced by the bacterial digestion process, is combusted to produce electricity and heat. The dry solids are utilized as safe and cost-effective bedding for cattle. The third beneficial product is a virtually odorless liquid fertilizer. Proven to be more effective for crops than traditional manure spreading, this liquid fertilizer is advantageous to farmers and the environment due to the digester’s ability to eliminate most pathogens, such as E. coli, and remove up to 60 percent of phosphorus - a significant waterway pollutant.
With no shortage of manure in America’s Dairyland, biodigesters appear to be a promising way forward for the state. However, there are a few limitations. Because low coal prices will continue to satisfy a utility’s desire for cheap power, buy-back rates from biodigesters and other renewable energy sources will likely not be able to compete with non-renewable rates. And, despite a biodigester’s many cost-saving benefits, they often require large, multi-million dollar investments that are rarely feasible for small to mid-sized farming operations. Due to the cost and efficiency limitations barring many from entering this sector of the renewable energy market, I recommend that Wisconsin’s Public Service Commission take an independent look at solar, wind and bioenergy so that manufacturers are reimbursed according to the efficiency of the energy source.
As the nation’s dairy state, it is undeniable that our unlimited supply of farm waste is an untapped wealth of potential - not only to reduce our reliance on fossil fuels, but to continue to support one of our state’s largest economic drivers. I believe that with continued innovation, biodigester technology can help our dairy farmers power Wisconsin’s way forward for centuries to come.
Representative Jesse Kremer