BC Hydro says the massive Site C dam project in northeastern British Columbia has started generating power.

The provincial electric utility says in a statement that the first of six generating units on the Site C dam has begun operations after completing testing and commissioning procedures.

It’s expected that the site will be in full service by fall 2025, adding about eight per cent more supply to B.C.'s electricity grid.

BC Hydro says the reservoir is now reaching more than 90 per cent full, with the water level at the dam rising by about 40 metres since late August when the filling process begun.

The utility is also warning people to stay away from the area of the reservoir for at least one year after it has been filled, citing possible unstable terrain and floating vegetation debris as potential hazards.

BC Hydro says the reservoir filling is anticipated to be completed later this fall.

Construction of Site C project was launched in 2015 under Christy Clark's B.C. Liberal government and has seen cost estimates spike from up to $6.6 billion in 2007 to $16 billion in 2021.

The project continued under former BC NDP Premier John Horgan after he said the dam needed to be finished despite his party not supporting the start of construction in the first place.