South Platte Renew (SPR) has reached a major financial milestone with its Renewable Natural Gas (RNG) System, the first of its kind in Colorado. Since becoming operational in October 2019, the system has generated approximately $11 million (€10.3 million) in total revenue.
The RNG System converts biogas produced during the wastewater treatment process into pipeline-quality renewable natural gas, which is injected into Xcel Energy’s natural gas network.
In July 2025, five and a half years after startup, SPR fully recovered the initial capital investment of $7.8 million (€7.3 million), jointly financed by the Cities of Englewood and Littleton Sewer Funds.
From August 2025 onwards, the system will generate positive revenue, helping to offset sewer treatment rates for customers in Englewood, Littleton, and 19 other sanitary sewer districts in the southwest metro area. The milestone was achieved within the original four-to-seven-year payback estimate.
Before the RNG System was built, most of the biogas was flared, contributing to greenhouse gas emissions. By converting it into renewable fuel, SPR has reduced emissions by approximately 3,700 metric tons of carbon dioxide per year — equivalent to eliminating nearly nine million car miles annually. Since 2019, SPR’s system has offset nearly 54 million miles in vehicle emissions.
Looking ahead, SPR expects to generate around $2 million (€1.9 million) in annual revenue from the system. The organisation will continue to focus on lowering operating costs, improving efficiency, and minimising energy use to maximise value for customers.
The RNG System’s success reflects the vision and support of the Cities of Englewood and Littleton and has earned recognition at local, national, and international levels.
SPR acknowledged the contributions of partners including Xcel Energy, Carollo Engineers, Filanc, and Anew Climate for their roles in the project.
Colorado RNG System pays back initial investment five years early
