Say green energy, and the first words that spring to most minds are likely either solar power or wind power. But there’s another important player in the alternative energy marketplace─biogas generation.

Biogas is produced when organic matter breaks down in the absence of oxygen. It’s produced by anaerobic digestion by bacteria or fermentation of biodegradable materials such as manure, sewage, municipal waste, or plant material. Like solar and wind power, it’s a renewable energy source. It can be used as a fuel in a variety of applications; when cleaned and compressed, it can power motor vehicles.

In the United States, anaerobic digesters for farm animal waste are typically large, heated stainless steel tanks fitted with tightly sealed sight glass windows to allow operators to monitor mixing and digestion to ensure efficient operation. These biogas sight glasses are often equipped with explosion-proof LED lighting and cameras, as well as spray nozzles and wipers to keep the window clean despite the often-messy process material. To learn more about what goes into matching the sight glass to the application, watch our new video: “Biogas Sight Glass Use and Selection.”