Faulty concrete is forcing Canadian utility NB Power to evaluate the long-term viability of its 672-MW Mactaquac hydroelectric plant, HydroWorld.com has learned.
Completed in 1968, the Mactaquac Generating Station was intended to have a 100-year lifespan.
The concrete used in the Mactaquac dam's spillways and generating stations is suffering from alkali-aggregate reactions, however, which are causing the concrete to expand.
NB Power Gaetan Thomas said the utility has three options, which include the replacement of the complex's concrete structures and the installation of new generators and turbines; decommissioning the powerhouse but continuing operation of the dam; or removing the dam in its entirety.
Sources report a complete rehabilitation of the dam could cost as much as US$3 billion, and since the structure poses no immediate threat, NB Power said it will take its time to determine Mactaquac's fate.
The hydropower project currently supplies approximately 20% of the province's total power, and a highway that runs across the dam connects the banks of the St. John River.
NB Power said it anticipates studies and public consultations about the Mactaquac's future will likely begin next year.