Jessica McDonald told a Vancouver Board of Trade luncheon that the dam in northeastern British Columbia is the "most-studied" project in the company's history.
"We've researched and consulted over a period of almost eight years. It's been evaluated against every other option. It's the clear winner to provide affordable, reliable power," she told the crowd.
Construction on the project is set to start this summer on the Peace River, where it will flood agricultural land, First Nations spiritual, burial and archeological sites and destroy hunting and fishing areas.
Environmental groups, ranchers and First Nations have vowed to fight Site C, with some First Nations taking their opposition to the Federal Court of Canada for a judicial review.
McDonald said after the speech that she is done selling Site C.
"We're moving forward now into implementation," the CEO told reporters. "(We're) really looking forward to having continued conversations about this project, but we're really, at this stage, past the decision point with the final investment decision being made by government."
The province approved the project in December. Now, BC Hydro is waiting for the government to finish its permitting process while it uses the time to carry on discussions with local residents and First Nations, McDonald said.
She shrugged off questions about a contingency plan if Site C is delayed or struck down in the courts.
"Our plan is to build Site C, and as I said before we're moving forward with implementation."
During her speech, McDonald said the utility is facing several challenges, including aging infrastructure built in the 1960s and '70s, and electricity demands that are expected to rise by 40 per cent over the next two decades.
"It's a new era for BC Hydro," she said about the scale of the Site C project. "It's like adding a company to the company."
BC Hydro's capital spending will increase to $2.4 billion a year from $1.7 billion annually over the next eight or nine years as the dam is constructed, McDonald said.
Site C is expected to meet just 22 per cent of upcoming energy demand. McDonald said the remaining three quarters of demand would be met largely through conservation — by convincing consumers to use less electricity and through new technology such as smart meters.
As for the Bank of Canada cutting its key interest rate to 0.75 per cent on Wednesday, McDonald said that's good news for her company's capital plan.
"The longer that we see interest rates carrying on low, that's very good for us and very good for our budgeting."
— With files from Dirk Meissner