Manitoba Hydro will begin work this summer on the $5.6 billion Keeyask generating station.
The project will generate another 695 megawatts from the Nelson River, which already produces almost 4,000 megawatts.
The project was given the green light last month when an export deal was signed with Wisconsin and Minnesota.
A number of Manitoba First Nations — Tataskweyak Cree Nation, War Lake First Nation, Fox Lake Cree Nation, and York Factory First Nation — are partners in the project.
They will have the right to up to 25 per cent with Hydro owning the rest.