On-Site Power Generation Protects Water Supply at Ontario Utility

By Mohamed Morsy

The town of Ajax, on the north shore of Lake Ontario, has a martial history. It was named for the HMS Ajax, a Royal Navy cruiser that gained fame in several key naval battles of World War II. The ship, in turn, was named for the figure from ancient Greek mythology famous for his strength and courage in battle. The town grew up around a defense plant established in 1941 to make shells for the war effort. Today, Ajax boasts a population of over 90,000 and is considered part of Greater Toronto in the area known as the Golden Horseshoe.

Inside the main facility of the Ajax Water Supply Plant

The Ajax Water Supply Plant treats and distributes water for the town of Ajax and the nearby city of Pickering. The operations staff of 25 manages two other treatment plants that supply the city of Oshawa and, through a remote system, the town of Whitby. The staff also manages a dozen pumping stations, reservoirs and elevated tanks in the region.

The Ajax plant requires approximately 2 megawatts (MW) of continuous power during peak water demand to supply the 150,000 customers it serves. Although local utility power is reliable, standby power generators are mandated by the Ontario Ministry of the Environment (MOE).

Like many water treatment plants, Ajax has reservoirs and elevated storage for backup water supply. However, when the utility power goes out, problems can result in the plant and system. Peter Cameron, district supervisor of plant operations, cited examples: "Water hammer occurs, caused by the flow stoppage and reversal. This can damage water mains and result in customer complaints due to disrupted service. At the control center, you get a tremendous influx of alarms, which can distract attention from conditions that require more immediate action. The entire plant can be disrupted."

The Ajax Water Supply facility serves a population of 150,000 customers along the north shore of Lake Ontario in Canada.

To avoid these potential problems, Ajax Water Supply staff selected Cummins Power Generation to provide a standby power system. The company was selected on the basis of its product design, integrated paralleling switchgear and the ability to provide the entire package exactly as specified.

Barry Pretty, diesel technician with the Region of Durham, said the installation was routine. "I dealt directly with Cummins Ontario. They know how we want things done and they do them, so the installation was trouble-free."

Cummins Ontario delivered one 350 kW and two 1500 kW generator sets, along with automatic transfer switches and paralleling switchgear. These digital systems parallel and synchronize the generator sets with each other and with the utility. There are paralleling controls mounted on the generator sets, as well as a separate digital master control unit for supervisory functions.

"With the complexity of this plant, being able to provide continuous service is a tremendous advantage," Cameron said. "If we had standard transfer switches, with blips and time delays from power going off and on, it would complicate operations. This paralleling system has been a real benefit."

Two 1500 kW generator sets were installed at the Ajax Water Supply facility.

For security reasons, the managers at the Ajax facility wanted the generator sets to provide read-only monitoring in the control room. This precaution prevents inadvertent changes or accidental command execution during emergencies.

The Ajax plant is designed to allow for twice its current capacity, including room for more generator sets and fuel storage. Beyond being prepared for future expansion, the power generation system is also ready for peak-shaving and other non-standby applications, at least between the hours of 7 am and 7 pm. Operating beyond those specified times - except in the case of a power outage - would require changes in the provincial regulations that govern the plant's operations. In any event, the Ajax Water Supply Plant is ready to handle future requirements.

About the Author: Mohamed Morsy is Business Development Manager, Canada, at Cummins Power Generation.

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