Renewable methane production from waste matter and other carbonaceous feedstocks is an important energy production pathway that offers multiple benefits, including: zero or negative carbon intensity power and/or fuels, significant reduction in criteria and toxic emissions, elimination of waste landfilling, improved energy security by using distributed local resources. Currently, RNG is commercially produced only through landfill gas upgrading and anaerobic digestion (AD) of organic waste.

However, renewable methane production projects using digesters often have poor project economics due to technology limitations. Speeding methane production from AD of wet wastes will make energy conversion more economic at locations currently flaring biogas, make new anaerobic digesters more economic, and help hold down dairy, meat, and wastewater treatment costs due to the improved water treatment, reduced transport costs of spent feedstocks and increased bio-methane production. Additionally, these industries provide a substantial source of renewable energy for either upgrading for vehicle fuel or use in cogeneration systems (heat and power).

CRNG is currently involved in a real world demonstration of an innovative technology that can double methane production rates from existing and new digesters at low costs. The technology, developed and owned by Perlemax, a UK based company, involves the use of CO₂ microbubbles to enhance methane production from anaerobic digestors. The demonstration will be conducted at one of the digestors operating at the City of Riverside’s wastewater treatment facility. CO₂ microbubble improvement of AD may change the U.S. approach to bioenergy, particularly that from wet biomass such as microalgae and macroalgae. Faster and/or more energy from anaerobic digestion improves economics for every conversion process: huge ambient temperature stand-alone digesters, digesters after fermentation, digester before or after hydrothermal liquefaction, and digesters after squeeze-oil operations. The technology can also play a key role in reducing net Short Lived Climate Pollutant (SLCP) emissions, a critical step in addressing climate change.