Imagine a tunnel more than ten stories underground, a hundred years old, brick-lined, wet, and completely inaccessible. Now imagine that this tunnel flows into Niagara Falls, emerging behind the pummeling curtain of water that nearly everyone in North America journeys to see at some point in their lives. This tunnel exists. It starts at the Electrical Development Co. (later known as the Toronto Power Co.) building which is behind you. This power plant has an outlet tunnel which is 33 feet/10m in diameter and 2,000 feet/610m long! It was the largest of its kind in the world at the time. Hydroelectric generating stations work by capturing the kinetic energy of falling water and converting it into mechanical energy using a turbine and then into electricity in a generator mounted at the other end of the turbine. At the beginning of the twentieth century, this technology had just begun to reach industrial maturity, and something of a race developed among competing private interests to capture the gravitational potential of the most spectacular water feature in Eastern North America, Niagara Falls.
Ontario Power Company, laid great conduits beneath the land along the upper river, and took up residence on a thin strip of useable land in the gorge just downstream of the Falls. Water was collected from the river by a wing dam which extended 735 ft/224m into the river. The water passed into the for-bay and down through 10.5 feet diameter steel penstocks to the turbines in the gorge. The station operated 11 turbines producing a total output of 137,000 horsepower.
The plant ceased operations on Feb.15, 1974 as Ontario Hydro looked to make a better use of the available water downriver at the Sir Adam Beck Stations in Queenston.
The vacant plant was designated a National Historic Site of Canada in 1983. The NPC is its current owner and hasn’t found a reuse for it yet.