NBPower said new studies have shown that its Generating Station,which it expected to shut by 2030 because of unstable concrete in thepowerhouse structure, could remain in service beyond that date.
The province-owned electricity utility had planned to shutthe hydroelectric facility and remove or rebuild its concrete structuresbecause of expansion problems in the concrete. Through advances in technology,NB Power said that in recent months it has changed its stance and opened thepossibility of repairing the existing plant. It had previously estimated thecost of refurbishingthe facility at as much as C$5 billion.
NB Power plans to release an update of its options for theplant at a series of public meetings later in May in various locations acrossNew Brunswick. The company said the results of environmental and First Nationsconsultations would be similar to other plans for Mactaquac.
"In recent months, technology has allowed for moredetailed modelling of actual and potential impacts of the concrete expansion atMactaquac, revealing better structural integrity than was previouslyunderstood," NB Power said in a May 6 statement. "These results areconsistent with ongoing testing of concrete samples taken from the station.This improved understanding has provided NB Power with greater confidence inthe potential for alternative approaches to allow Mactaquac to generate electricitybeyond 2030, perhaps even to its original 100-year service life."
Mactaquac, which started generating power in 1968, wasexpected to be shuttered early because of concrete problems known asalkali-aggregate reaction that affect the powerhouse and spillway. The earthendam on the St. John River, which holds back a head pond approximately 96kilometers long, is not affected by the problem. The plant has a capacity of668 MW.
Previously NB Power had proposed either removing the dam andother structures completely, leaving the dam in place and removingpower-generation equipment, or building a new generating structure across theriver from the current site. Since the new information has come to light it isconsidering repairs or replacement of concrete and equipment to extend the lifeof the station.
"Our goal is to make a sound and lasting decision aboutthe future of Mactaquac that makes good business sense and is one that all NewBrunswickers can live with and afford," NB Power CEO Gaëtan Thomas said inthe statement. "At the start of this decision process, we committed tosharing and considering new information as it became available. We are livingup to that commitment."