The Lower Mattagami River Project

Ontario Power Generation has a mandate from its sole shareholder, the Province of Ontario, to "expand, develop and/or improve its hydroelectric generation capacity" within the province. There are three proposed hydroelectric developments/re-developments on the Mattagami River within the Moose River Basin. The projects are the Lower Mattagami River Project, The Upper Mattagami River Re-development Project, and a new Hydroelectric Development at the Mattagami Lake Dam. The map below shows the location of the Lower Mattagami stations.

The terms upper and lower refer to flow of the river, the upper being the area "up-river" near Timmins, the lower being the area "down river" near James Bay.

Each of these projects will bring more clean, renewable, hydroelectric energy to Ontario helping to reduce our carbon footprint while improving our efficiency in use of existing waterpower resources. For more information on the Upper Mattagami projects see

Lower Mattagami River Project
The Lower Mattagami River Project proposes redevelopment of the Smoky Falls G.S., and extension of Little Long G.S., Harmon G.S., and Kipling G.S. Work on the commercial feasibility of the project has been completed and OPG is in now in the process of discussion with Aboriginal peoples addressing Environmental Assessment requirements.

Proposed Changes to the Lower Mattagami Hydroelectric Complex
The Lower Mattagami Hydroelectric Complex is made up of four generating stations on the Mattagami River. The four stations are (from north to south): Little Long, Smoky Falls, Harmon, and Kipling. They are about 70 kilometres northeast of Kapuskasing and about 150 kilometres upstream of Moose Factory and Moosonee.

Smoky Falls was built in 1931 and right now it has a capacity of about 50 megawatts. (One megawatt produces roughly enough electricity for 1,000 homes. )This station is older and smaller than the others and does can not make effective use of the water passed through by the other three plants. OPG wants to replace it with a generating station that could make efficient use fo the available water. This would mean building a new generating station next to the old one. There would be new manmade structures such as an approach channel, intake and tailrace. The new generating station would be able to pass more water and would have a size of almost 270 megawatts. The old dams and spillways for the station would remain.

Little Long, Harmon and Kipling were all built in the mid-1960s. Each station has two generators to make electricity. Little Long has a capacity of 135 megawatts. Harmon is 140 megawatts. Kipling is 155 megawatts.

Since the proposed new Smoky falls dam would now be able to use more water efficiently, OPG is also intending to extend the capacity of the other three plants by adding a third generator to each of the three existing generating stations. Then the stations could use available water with the best possible efficiently and produce more clean, renewable electricity. Little Long would then have a size of 200 megawatts. Harmon and Kipling would each be about 240 megawatts. Together the whole project would add nearly 450 MW of capacity to the system and make even better use of an existing resource.

Once construction work is started it is estimated that it would take at least four years to complete all the work with a peak work force of about 600 people.

Improving the benefits from existing renewable energy sources and reducing our ecological footprint
The Lower Mattagami River project allows a significant amount of new energy to be produced without creating new dams on other rivers. This helps to reduce our load on the environment and keep our footprint small.

OPG received Provincial Environmental Assessment (EA) approvals to proceed with the Lower Mattagami Project and is in the process of securing Federal Approvals under the Canadian Environmental Assessment ACT (CEAA).

At this point the project is in the approvals phase. Our work includes discussions with Aboriginal peoples, detailed engineering and solicitation of proposals for project design and construction, addressing pre-construction Environmental Assessment and successful completion of a federal comprehensive study.