The Mactaquac Hydroelectric Dam was built in 1966 and was scheduled to operate for a century. (CBC)

NB Power officials say they will begin to consider whether to upgrade the Mactaquac generating station early next year, but critics say the utility should be moving faster.

Gaëtan Thomas, the president and chief executive officer of NB Power, told the legislature's Standing Committee on Crown Corps. on Tuesday the utility will have to make a decision between 2018 and 2020 if work on a new generating station is to begin around 2021.

But it will first have to consult homeowners on the headpond and First Nations and investigate the impact on the environment, including fish habitat, he said.

Thomas said he expects consultations on the hydroelectric dam, located about 20 kilometres northwest of Fredericton, to begin early in 2014, but said he's already hearing from people informally.

"We're actively engaged, so that'll give us some ideas of what the kinds of questions, what the kinds of concerns, that we would make sure to have in our hands when we start the environmental process," he said.

'Lots of issues' to consider

Green Party Leader David Coon said NB Power isn't moving fast enough on the issue.

Although 2018 may seem like a long time from now, Coon said it will arrive sooner than anyone thinks.

"We should be talking about those this decade and not putting those off to the next decade, because it's going to be a major, major decision and there's lots of dimensions to it," he said.

The Green Party has not yet decided whether to support a refurbishment of Mactaquac.

"On the one hand, you don't want to lose that renewable energy from the system at all," said Coon, referring to the carbon-free energy Mactaquac generates.

"On the other hand, there are lots of issues with respect to Mactaquac around the health of the St. John River," including the impact on fish, he said.

The party will take a position once it has a chance to hear from New Brunswickers, Coon said.

The cost of either upgrading or decommissioning the Mactaquac facility has been estimated to be between $2 billion and $3 billion.

The Mactaquac dam was built in the mid-1960s and was scheduled to operate for a century. But an ongoing chemical reaction in the concrete of the dam has led to its lifespan being shortened to 67 years, ending in 2030.

The future of the Mactaquac dam became a major public issue in 2010 when the plan to sell NB Power to Hydro-Québec fell apart.

Hydro-Québec indicated the complexity of upgrading the dam was one of the reasons they gave up on the power deal.

Mactaquac is the largest hydroelectric generation station in the Maritimes.