Cogeneration at the Kitchener, Waterloo and Galt Wastewater Treatment Plants

The Region of Waterloo will build three dual fuel cogeneration facilities at the Kitchener, Galt and Waterloo Wastewater Treatment Plants (WWTP). As the population in the region grows, the facilities will primarily use biogas from the wastewater treatment process to produce heat and electricity. This project aligns with the region of Waterloo’s multiple sustainability and energy strategic plans. The facilities currently use biogas to produce heat for plant processes and the building envelopes. When heating requirements are met, excess biogas is flared off. The installation of the cogeneration facilities will ensure year-round use of all the biogas and reduce each plant’s electrical consumption from the grid. The installation of dual fuel cogeneration engines will allow engines to operate with a blend of biogas and natural gas. At first, the engines will primarily use natural gas; however, the region’s projected increase in wastewater and associated biogas production over the next 20 years, will allow the cogeneration facilities to fully integrate biogas. The applicant will install the necessary instrumentation to calculate the performance of the cogeneration facilities once they are operational. The installation of the engines will displace electricity purchased from the grid by 50 to 80% at each of the wastewater plants. Once the scale of the cogeneration systems is met by the population increase in the region, the biogas to natural gas ratio for the Waterloo plant will be 88% to 12%, the Galt plant 77% to 23% and the Kitchener plant 71% to 29%. The more effective use of biogas will reduce flaring and its associated greenhouse gas (GHG) emissions by approximately 569 tonnes of CO2e or 14% during the first year of operation compared to current operating conditions. Modelling suggests that these reductions will increase to 2,409 tonnes of CO2e or 40% by 2041 as biogas volumes increase and supplemental natural gas decreases. Over the life of the cogeneration engines, the region will realize an estimated $16.6 million in net savings. Sizing the engines to utilize full range of biogas and supplemental natural gas maximizes the electrical output from each of the engines, and reduces the investment payback period from approximately 20 down to 10 years. The knowledge value of this initiative relates to the utilization of dual fuel cogeneration engines that enable the municipality to maximize electrical output over the lifespan of each engine. This will allow for a more efficient use of wastewater biogas in the region and will provide significant cost savings in terms of displaced electricity from the grid. (Project description from original funding application)