Energy Efficiency and Biofuel (E2B) Project

Biofuel Recovery Project

 The St. Cloud Wastewater Treatment Facility has installed biofuel conditioning equipment and a generator, to convert biofuel to electricity. Heat produced by the generator is recovered and used to heat buildings and the digestion process.

 Biofuel to Electricity - How Does it Work?

 Organic wastes carry energy to the digestion process. The digestion process extracts this energy in the form of biofuel. The biofuel feeds boilers to heat buildings and an engine-driven generator to produce electricity. The biofuel harvesting project converts organic wastes to renewable energy.
Diagram of the Biogas Utilization Process


  At 100% efficiency, the biofuel generator has the potential to generate 5.4 Million kWh's of electricity annually. Prior to 2016, The St. Cloud Wastewater Treatment Facility purchased nearly 6 Million kWh of electricity to treat 10 Million gallons of influent flow a day. 

In 2021, The St. Cloud Wastewater Treatment Facility generated over 98% of the required electricity on-site. When daily conditions are optimal (for example: no snow covering the solar panels) the facility can run at net zero - which means it is not purchasing any electricity from the grid.
With the addition of community solar garden subscriptions, St. Cloud creates or subscribes to over 100% of their annual energy demand. 
Diagram of energy use equivalencies for 5 million kilowatt-hours