Shepard Energy Centre is located in Calgary, AB, Canada. Operations began March 2015 and the center can generate more than 800 MW of electricity to Alberta residents using natural gas. The facility utilizes two combustion turbines featuring a combined cycle technology to generate electricity. In addition, it processes waste heat through a steam turbine to produce even more electricity.
This electricity generation process makes Shepard approximately 30% more efﬁcient than coal-ﬁred plants, which reduces overall fuel costs. Not only is the plant more efﬁcient, but it also emits less than half of the CO2 emissions per MW hour compared to a coal generated facility. Sulphur dioxide and nitrogen dioxide emissions also are reduced.
The facility uses up to 7.7 million gal per day (mgd) of reclaimed wastewater from the city of Calgary’s Bonnybrook Wastewater Treatment Plant (WWTP). This is the ﬁrst application of reclaimed water for power production in Alberta. The majority of this water is used for cooling tower water and boiler feedwater.
Enmax and Capital Power installed three eight-disk AquaDisk cloth media ﬁlter units to aid this process. Efﬂuent from the Bonnybrook WWTP is pumped through a 9-mile pipe to the Shepard Energy Centre. Water then passes through the AquaDisk cloth media ﬁlters before being sent to the cooling tower. Filtration is critical to prevent solids accumulation in the cooling tower.
AquaDisk Filter Process
Water from the Bonnybrook WWTP enters the ﬁlters and ﬂows by gravity through the cloth media of the stationary hollow disks. The ﬁltrate exits through the hollow shaft, which supports the individual disks, and ﬂows to the efﬂuent channel. As solids accumulate on the surface of the media, the water level surrounding the disks rises.
Once a predetermined level is reached, the disks rotate and the media surface automatically is vacuum backwashed clean. Heavier solids settle to the bottom of the tank and then are removed using a solids manifold. Both backwash and solids wastewater are sent back to the wastewater treatment plant.
The AquaDisk ﬁlters remove total suspended solids and reduce turbidity to protect the heat exchangers from clogging. This reduces energy consumption, and in severe cases, prevents plant shutdown. Shepard Energy Centre now is Alberta’s largest gas-fueled electricity generation facility.