Anaerobic digester technology : the potential for cow-powered sustainability

Abstract

Anaerobic digester systems break down manure and other substrates into their liquid, solid and gas components, all of which have valuable post-digestive applications, including electricity generation. Primarily due to their expense, all of the systems in Wisconsin (~30) are located on Concentrated Animal Feeding Operations (CAFOs) with 800 to 5,000 dairy cows. However, the majority of the state's cows are located on approximately 12,000 small to medium-sized dairy farms. The goal of the study is to assess the potential for farmers with less than 800 cows to form anaerobic digester cooperatives. Cooperatives may provide the advantage of scale these farmers need to remain competitive in the face of fluctuating milk prices and high operational costs, such as energy costs. The study utilizes GIS to locate possible sites in southeastern Wisconsin and a survey to assess farmers' interest in the technology and concerns related to the hurdles of adopting it.