Lambton Generating Station was a 2000MW coal fired power station, located on the St Clair River, 26km downstream of Sarnia, Ontario. During its operation the facility had continuing issues with gizzard shad (Dorosoma cepedianum) entering the intake and being drawn into the condensers, which at times caused some of the generating units to shut down.
The issue was worst during the winter months of December and January, when the gizzard shad would accumulate around the outfall of the plant due to the warmer water being released by the facility. Unlike many sites the outfall is located close to the intake, less than 100m upstream of the outfall, and when large numbers of the gizzard shad congregated near the outfall they could be drawn into the intake. It was estimated by Ontario Power Generation (OPG) that the plant lost an estimated CAN$20m in 2003 as a result of the fish entrainment into the plant.
OPG hired Kinectrics Inc., a firm of independent fisheries scientists and engineers, to review the options and they concluded a behavioural barrier was required and a combined acoustic and ‘strobe’ barrier was installed on a lease basis for evaluation in 2004. The ‘strobe’ lights were supplied by a US supplier, while Fish Guidance Systems (FGS) was requested to supply the acoustic system.
FGS carried out PrISM modelling to determine the optimum number and configuration of Sound Projectors to protect the intake, and the system was weighted to protect the downstream side of the intake closest to the outfall. Due to the high velocities entering the intake it was necessary to position the Sound Projectors a little way in front of the entrance to the intake, and a walkway was designed by Kinectrics to provide access to the Sound Projectors.
The PrISM modelling indicated that 18 FGS MKII 30-600 Sound Projectors were required, with nine of the projectors located on the downstream side of the intake. A separate Model 400 Amplifier was supplied for each of the projectors and the required acoustic signal was supplied by a Model 1-08 Signal Generator.
The system was evaluated by Kinectrics’ scientists over a period of three years and they concluded that the acoustic system provided an overall reduction in entrainment of between 73% and 84%, although deflection efficiencies of up to 90% were reported.
OPG stated ‘the fish diversion experiment at Lambton Generating Station provides an excellent example of a cost effective way to increase production and profit while reducing the industrial footprint on the local environment’.
Due to reliability issues it was concluded the ‘strobe’ lights were not required and so FGS was requested to install the acoustic system on a permanent basis in 2008. As part of the final installation FGS was requested to reduce the number of Sound Projectors so that only the nine Projectors on the downstream side of the intake, closest to the outfall, remained. As a result the Sound Projectors protecting the upstream side of the intake were removed from the system, but no detrimental impacts were observed after the projectors were removed.
FGS subsequently provided a maintenance contract for the system to ensure it continued to operate in an optimum condition.
As part of Ontario’s provincial government commitment to close all of the coal fired power stations in the province, Lambton Generating Station was closed in September 2013. There are potential plans to convert the station to natural gas however, the future of the station has not yet been finalised.