The Ontario Generating Station:
A building 'of modest though massive design'

Niagara Falls, Ontario. Commissioned 1905. Decommissioned 1999.
Michael Cook

Archival Material:

At Niagara Falls, the history of power development has been rendered largely invisible, brushed aside by the demands of tourism and the priorities of the public hydro authorities who controlled most of the infrastructure for the last ninety years. While some would say that the triumph of hydroelectric development is celebrated at the modern Adam Beck installation downriver at Queenston Heights, at best this facility is the blandest possible monument to the victory of the public power movement in Ontario, accessible to the public for an extremely cursory and unfulfilling 'tour' whose highlight, like many of Niagara's other attractions, is the elevator ride. Meanwhile the three commercial generating stations that had preceded it on the Canadian side, built by private investors from both sides of the border, seemed almost predestined to fade into obscurity.

Paul N. Nunn, who with his brother Lucien had pioneered the use of alternating current (AC) at Telluride, CO, observed in 1905 that the "widespread attention and interest" that had been attracted to the opening a decade earlier of the Adams station on the American side had not accrued to the second generation of developments that followed. 1 While they were impressive engineering and commercial achievements, the subsequent move to public power ownership ensured that these stations were doomed to be subsumed as minor elements of provincial and state utility systems that for the next 75 years devoted themselves to expanding demand and production to levels that dwarfed the capacity of these older plants. Institutionally irrelevant, these plants stayed operational as long as they did thanks only to water rights that were legally vested in the individual facilities.

The Ontario Power Generating Station, for which Nunn served as Chief Engineer, is a case in point. Its generating equipment long obsolete, by the 1970s it stayed in operation only to maintain rights to water now being withdrawn from the river to drive the turbines downriver at Adam Beck II. By the late 1990s, the station was only manned for a couple weeks annually, as technicians would come in to restore a single generator to service in order to operate for the prescribed period necessary to maintain the water rights.

When built, however, the Ontario Generating Station was a marvellous achievement. Nunn describes its layout in detail, and with a certain reverence in his recitation of the plant's numerology:

"From the head-gates of the Ontario company three great steel-and-concrete tunnels or conduits beneath the surface of the park, will convey nearly 12 000 cubic feet of water per sec. to the top of the cliff above the power-house. Thence it will pass through 22 steel penstocks in shafts and tunnels down and out through the cliff to an equal number of horizontal turbines in the power-house below. From the generators the electrical cables turn back through tunnels to the 22 banks of switches, transformers and instruments of the distributing station above and to the transmission lines beyond, completing an equipment for more than 200 000 h.p." 2


Despite its name, the Ontario Power Company was a private, American-owned firm that applied successfully in 1901 for a share of the water flowing over Niagara Falls. This decision from the cash-strapped Niagara Parks Commission broke the monopoly on Canadian water rights previously held by the Niagara Falls Power Company (another American concern) in exchange for a two year deposit on the new company's water lease. The company jumped quickly into action, building its powerhouse below the Horseshoe Falls and laying the first of three 1.8 km long intake conduits in just four years, allowing the first units of the plant to enter service in 1905.

During its first five years of service, the plant sold 35,000 horsepower (26 MW) of power to the Niagara, Lockport and Ontario Power Company, which distributed electricity to the region of New York State around Rochester and Syracuse. In 1910, Ontario's new public power authority, then called the Hydroelectric Power Commission of Ontario (HEPCO) signed a contract to purchase 100,000 horsepower (74.5 MW) of 25-cycle power from the Ontario Power Company. With HEPCO expanding rapidly to service and promote consumer and industrial power needs throughout the province, the Ontario plant would soon be purchased outright by the provincial utility in 1917.

Though the Ontario Power Generating Station produced 132.5 MW of electricity at its peak, the expansion of the higher-capacity Sir Adam Beck complex downriver at Queenston Heights, and the progressive conversion of hydro customers to 60 hz power, rendered the facility increasingly obsolete as the century wore on. The plant was decommissioned in 1999, and agreements were concluded in 2006 for the transfer of this plant as well as other Niagara properties to the Niagara Parks Commission.

Exploring the Distributors

The promise of massive, empty tunnels beneath the Niagara Falls Parkway had fascinated my colleagues and I since our first explorations of the Toronto Power Company plant in 2003. When work began on sealing these tunnels as part of remedial activities connected to the transfer of all of the decommissioned hydro sites at Niagara from OPG to the Parks Commission, we took advantage of the only practical opportunity we'd ever have to enter these tunnels that nearly everyone had forgotten.

The sealing teams in the gatehouse worked in sequence, first on the No. 2 and then later the No. 1 Distributor, dismantling their heavy steel inner gates and then pouring a new concrete bulkhead to prevent further flow from the river. As they did this, with ladders and later scaffolds, they gave us a few brief weeks of access to two of Niagara's truly hidden wonders. The first time we ventured into the No. 2 conduit, ladders only took us as far as the top of its inner gate — to reach the floor of the tunnel we had to climb down through the lattice of the old gate's support struts. The next time we returned, the gate was gone, and scaffolded stairs made the trip to the bottom far easier.

Despite the seven intervening years since the plant's turbines had been silenced, both conduits still sat in the spell of the adjacent river. They housed thriving colonies of zebra mussels, and in the No. 2 tunnel we even found a mudminnow that seemed quite satisfied with the water and muck that still flowed along the pipe's bottom. The floor of the No. 1 conduit had buckled substantially at one point (the tunnel had been the victim of a collapse during dewatering early in its history) and this location was spraying either groundwater or headwater infiltrating from upstream through a number of specially-designed appliances that had been added to the metal liner. The 1.8 kilometers of pipe in each conduit was nearly featureless, yet the hike was fascinating and never boring. The conduits also had gorgeous resonance, making for some fantastic acoustical experiences.

Reaching the downstream end of the passable length of each conduit was both exciting and disappointing. Here, the otherwise all-concrete No. 2 Distributor returned to the steel plate construction of the older No. 1 conduit, and in both tunnels the openings of the distributor's penstock pipes gaped thirstily from the floor. Each offered a sheer drop the depth of the gorge. Beyond the penstocks, we could see the physical end of the distributor, as well as surge pipes reaching from openings in the ceiling up towards their spillway structures. There was also a tantalizing though inconclusive prospect that a connection might exist between the two distributors.

However, the penstock openings were too wide to safely skirt, as falling into them would have meant nearly certain critical injury or death, and I could feel a visceral sense of dread anytime I got close to the first pair of penstocks in either distributor. All we could do was illuminate the conduits' puzzling conclusions from a distance, and then turn around for the trek back to the gatehouse.

System Walkthrough

From an elaborate forebay positioned amidst the cascades on the upper river, water dropped through a gatehouse into one of three separate intake conduits. Each Distributor, as they were called, was a unique construction, the product both of trial and error and the materials available at the times of their successive constructions. The No. 1 Distributor, the first to be laid, consisted of tens of thousands of curved steel plates riveted together and encased in concrete. Built to withstand the internal pressure of water flowing within it, a section nevertheless collapsed under a partial vacuum when the conduit was drained for inspection, necessitating further reinforcement. The No. 2 Distributor was built in reinforced concrete, though where it reached its penstocks it reverted to the steel plate of its older companion. A smaller third distributor was laid near the end of the First World War, and due to wartime material shortages was composed of wood staves and steel bands later reinforced with concrete. This No. 3 Distributor was eventually converted for use in park irrigation after one of the generators it serviced exploded and the other was removed from service.

Following the gentle curve of the river's shoreline, the distribution conduits ran 1.8 kilometers to the area immediately above the powerhouse in the gorge. Here, the water they carried fell 180 feet through near-vertical steel penstocks to the plant's turbines. Valves positioned in a long chamber just below the distributor tunnels controlled the flow of water into the penstocks, allowing units to be taken out of service individually despite the fact that many other turbines were driven by each distributor. Excess water in the distributors could also flow upwards through pipes into a surge structure which drained the overflow into the lower river by way of helical spillways that descended behind the plant before emerging through the face of its concrete draft wall. Two of the surge structures remain in the park; both are open-topped and are used as a base for the high-powered lamps that light the falls at night. The oldest is a rectangular chamber and weir, while the No. 2 Surge Tank is a cylinder with a spout in its centre and a spillway beginning around the outside of this spout. The No. 3 Surge Tank was demolished after its units were removed from service.

Reaching the powerhouse, the gravity-accelerated water originally drove more than a dozen turbines of various sizes. Once its power was exhausted in this way, the tailwater passed from the turbines into the discharge bays that line the front face of the plant. When the Ontario Power Generating Station was in service, the water rushing out of these bays and over the lip of the draft wall would have been a spectacular sight.

Built into the cliffside of the Niagara Gorge, the architectural design of the powerhouse resembles any of several Egyptian mortuary temples, such as that of Hatshepsut at Deir ei-Bahri. Inside, the walls are inlaid with an Egyptian revival motif. The powerhouse of the Ontario Generating Station lacked some of the classical elegance and the well-appointed executive offices of its neighbours upriver (instead, senior personnel were housed in more easily accessed buildings above the gorge, such as the Transmission House demolished to make way for the Fallsview Casino), but it made up for this in its durability. Twice during its operational history ice jams built up on the river and crashed into the plant, flooding it with ice and water. While some damage occurred during both these events, it was possible to quickly clear the plant and return it to service.

Helical Spillways

To my knowledge, no one has taken any photos half-way up either of the two Ontario Power Company spillways. This deficit isn't from a lack of interest — they're both fascinating constructions and beautiful in their decay — but rather a function of the difficulty of even being there. The pipes ascend from riverside to park (or rather descend in the reverse) at such a severe angle that their helical curvature is the only thing that makes it possible to ascend them without ropes at all.

Without the extra surface area provided by these pipes' constant curve, it wouldn't be possible to maintain traction, a task further complicated by the layer of rusty grit layed down by adjacent oxidation and the slight flow of water that continues as a result of weather (the surge structures are open to the sky) and infiltrating groundwater. As it was, on our descent in the No. 2 Spillway, after failing to reach the surge tank because of the extreme angle, I lost traction and slid at high speed most of the two hundred feet to the bottom of the helix. I was lucky to avoid serious injury, suffering only a few painful friction burns and a sprained thumb.

Despite the horizontal orientation of its generation units, the plant required extensive underground workings. As mentioned, a long, twisting valve chamber housed the mechanisms governing waterflow from the distributor conduits into each penstock, and this chamber itself sat atop a number of sublevels of narrowing chambers through which each several-metre-thick penstock had been run. No less than three separate cable tunnels connected the plant's dynamos to the transmission house above the park, from which power flowed first to Western New York and later to the expanding Ontario grid. Two elevators facilitated worker access to the plant and movement between it and the transmission house, with extensive personnel tunnels covering the horizontal distance between the elevators. Some of these spaces now feel medieval, while others are more akin to what one might find in a Cold War-era bunker complex.


Most of the station's underground components remain in place, though work performed by Kiewit Sons Co. in 2006 to prepare the building for transfer to the Niagara Parks Commission has sealed the majority of their access points, including the inlets of the Nos. 1 and 2 Distributor conduits. The powerhouse itself has been completely cleared of its turbines and control equipment, leaving it a dusty, empty space. The photos linked on this page are among the last records of what the plant's structures looked like before being sealed or renovated.

Illustrations originally published in Paul N. Nunn. 1905. The Development of the Ontario Power Company. Scans provided by the Niagara Falls Public Library. Composite diagram produced by Michael Cook. Photographs by Michael Cook 2003-2006.

  1. 1. P.N. Nunn. 1905. "The Development of the Ontario Power Company." A paper presented at the 22nd Annual Convention of the American Institute of Electrical Engineers, Asheville N.C., June 19-23, 1905.
  2. 2. Ibid.
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