Canadian utility Bruce Power is starting early work to expand the Bruce nuclear station, potentially building the world’s biggest commercial nuclear facility as growing demand for low-carbon energy spurs interest in nuclear power.

The Ontario government said Bruce Power will carry out an environmental assessment for adding as much as 4.8 GW of capacity to its Bruce station in Ontario, Canada’s most populous province. The facility’s eight Candu reactors have almost 7 GW (gross) of capacity and supply 30% of the province’s power.

The expansion would make the site larger than Japan’s Kashiwazaki-Kariwa station, the biggest in the world with seven units and more than 7.9 GW (gross) of capacity, although operation of all those units has been suspended since the 2011 Fukushima disaster.