A Biogas Heat Engine for Small to Mid-Sized Farms

Non-technical Summary: The profitability of small and mid-sized dairy farms is strongly affected by increases in feed costs and energy costs. Unfortunately, farm operators have limited control of these factors, especially in the long term. New technology is needed to allow farmers to manage energy costs on their farms. One excellent solution is to use existing organic farm waste material to create energy via anaerobic digestion. Dairy operations (as well as other feeding sites) create copious amount of manure each day. By collecting this waste into an anaerobic digester, valuable biogas can be created and used by the farmer for pasteurization or hot water generation. Other organic materials can be used as feedstocks to enhance biogas production. The Biogas Heat Engine from Quantalux is an energy solution that generates valuable biogas from agricultural waste. Biogas has a large fraction of methane, and with suitable cleaning of the gas, can be used as a drop-in replacement for fossil fuels such as propane and natural gas. Our system includes a novel method for stabilizing biogas production using a thermal energy storage (TES). Renewable thermal sources are coupled to the Heat Engine via thermal storage cache, allowing the system to produce biogas more consistently. In order to show the viability of this technology for smaller farming operations, Quantalux will prototype and demonstrate that a simplified, thermally stable anaerobic digester system, We will show that the smaller farmer can self-generate biogas for use on his/her farm (decreasing energy costs), and that same farmer can also earn additional revenue (from selling enhanced digestate.) We also will show enhanced biogas production via the use of thermally stabilized digestion vessels, and by the addition of different farm-based feedstocks to the base manure feedstock. The Biogas Heat Engine will be marketed directly to small to mid-sized dairy farmers who seek decreased costs and a diversified revenue source. Revenues come from avoided cost of energy, the sale of compost, or from tipping fees from co-digestion materials. The Biogas Heat Engine is a way for the small farmer their energy costs while improving the health management of their farm and of the surrounding ecosystem.