Biogas produced from anaerobic digestion at a dairy farm can be utilized in several ways. To date in New York State, biogas has been predominantly utilized to fuel combined heat and power (CHP) systems to produce electricity and digester heating energy. The commercially available CHP technology options are compared in Table 1. Other biogas utilization options include fueling a boiler and producing renewable natural gas (RNG) that is suitable for either vehicle fueling or natural gas pipeline injection. This fact sheet series will describe each of the four primary CHP technology options with information on dairy farm applications, biogas conditioning requirements, capital and operating cost, and emissions. In addition, the series will describe the options of utilizing a boiler and producing RNG. This fact sheet (Part 1) contains an overview of the CHP options.