Anaerobic digesters at Hamilton’s Woodward Avenue Wastewater Treatment Plant produced six million cubic meters of biogas per year at 65 percent methane. The plant burned some of the gas in a boiler for heating, but flared the majority of it. Seeing the gas as a source of renewable energy, the city responded to a Request for Proposals from the Ministry of Energy with plans for a 1.6-megawatt (MW) cogeneration facility fueled exclusively with digester methane. The project would also ultimately meet a need for increased backup generation at the treatment plant, as identified by a power study.
The Ministry selected the city’s proposal through competitive bidding, based on the price of energy per kilowatt-hour. It was one of ten winning projects totaling 395 MW of renewable generating capacity. The city then turned to Toromont Power Systems in Concord, ON, which had developed the project proposal, to build, operate, and maintain the cogeneration plant.
Solution
To generate electricity, the city formed a corporate entity under the Ontario Business Corporations Act (OBCA) called Hamilton Renewable Power Inc. (HRPI), with the City of Hamilton as the sole shareholder. Toromont Power Systems, which in 2002 had supplied the city with a 3.5-MW Cat G3616 gas generator set for a district energy project in the downtown area, took turnkey responsibility for this renewable energy project. The local office of Conestoga Rovers & Associates provided engineering and project management support through construction.Toromont delivered the complete cogeneration system in a stand-alone module with a sound-attenuated enclosure. At the heart of the system is a Cat G3520C gas engine in a configuration designed to be durable and reliable in burning low-energy fuels without needing extensive fuel conditioning.
A specially designed cooling system elevates jacket water to the optimum temperature to prevent condensation of fuel-borne sulfur compounds and the formation of sulfuric acid, which can damage engine components. A crankcase ventilation pump ejects potentially acidic blow-by gases and draws in fresh, filtered air. In addition, aluminum and unprotected steel are eliminated from key components, including after-cooler cores and main and connecting rod bearings.
“Because we chose this engine, the digester fuel conditioning system requires only a moisture removal system followed by a coalescing filter to remove remaining moisture droplets and particulate,” says Peter Ronson, Toromont account manager. “We made provisions to add other fuel conditioning steps in the future, but we do not expect them to be necessary.”
The enclosure contains jacket water and first-stage after-cooler heat exchangers and an exhaust gas boiler. Heated water from the engine passes through a plate-and-frame heat exchanger connected to the treatment plant process heat loop.
The package also includes 4,160-volt switchgear, utility interconnections, paralleling, and synchronization controls, and protective relaying. A PLC-based control panel designed and built by Toromont regulates the heat recovery and gas delivery systems, as well as the engine and generator.
Results
To generate electricity, the city formed a corporate entity under the Ontario Business Corporations Act (OBCA) called Hamilton Renewable Power Inc. (HRPI), with the City of Hamilton as the sole shareholder. Toromont Power Systems, which in 2002 had supplied the city with a 3.5-MW Cat G3616 gas generator set for a district energy project in the downtown area, took turnkey responsibility for this renewable energy project. The local office of Conestoga Rovers & Associates provided engineering and project management support through construction.Toromont delivered the complete cogeneration system in a stand-alone module with a sound-attenuated enclosure. At the heart of the system is a Cat G3520C gas engine in a configuration designed to be durable and reliable in burning low-energy fuels without needing extensive fuel conditioning.
A specially designed cooling system elevates jacket water to the optimum temperature to prevent condensation of fuel-borne sulfur compounds and the formation of sulfuric acid, which can damage engine components. A crankcase ventilation pump ejects potentially acidic blow-by gases and draws in fresh, filtered air. In addition, aluminum and unprotected steel are eliminated from key components, including after-cooler cores and main and connecting rod bearings.
“Because we chose this engine, the digester fuel conditioning system requires only a moisture removal system followed by a coalescing filter to remove remaining moisture droplets and particulate,” says Peter Ronson, Toromont account manager. “We made provisions to add other fuel conditioning steps in the future, but we do not expect them to be necessary.”
The enclosure contains jacket water and first-stage after-cooler heat exchangers and an exhaust gas boiler. Heated water from the engine passes through a plate-and-frame heat exchanger connected to the treatment plant process heat loop.
The package also includes 4,160-volt switchgear, utility interconnections, paralleling, and synchronization controls, and protective relaying. A PLC-based control panel designed and built by Toromont regulates the heat recovery and gas delivery systems, as well as the engine and generator.
