Dam Design and Construction

OPG updates on tailrace deck upgrade work at Sir Adam Beck I hydro station

OPG updates on tailrace deck upgrade work at Sir Adam Beck I hydro station
(photo courtesy OPG)

Ontario Power Generation (OPG) said work is almost complete on the upgrade of the 180-m-long tailrace deck spanning the lower façade of the 446 MW Sir Adam Beck I Generating Station.

For close to a century, this tailrace deck spanning the lower façade of the generating station served as an essential runway for workers to maintain the station’s 10 turbine-generator units. The laneway and its arches also played a large part in the overall aesthetic of the powerhouse.

Upgrading this important part of the station will secure 50-plus years of operation and allow for the safe passage of trucks, cranes and people supporting the facility, OPG said. The new tailrace deck is much wider – 5.87 m compared to the original’s 4.11 m. It’s also higher by 0.8 m to provide increased clearance above maximum tailwater levels. The new design is also preserving the heritage of the original tailrace deck by replicating its unique arches.

In addition to the deck upgrades, a permanent access platform has been built at the south end of the tailrace. The 20 m by 12 m platform will benefit OPG’s operations by providing a staging and parking area at river level.

The project started in 2022 in partnership with Hatch Ltd., Rankin Construction Inc. and Ellis Engineering. Complete demolition of the old tailrace deck wrapped up in September 2023. Proceeding from south to north, the reconstruction phase began shortly after, in October 2023, and construction is expected to be completed later this year.

The project team had to think outside the box to ensure hydroelectric generation from Sir Adam Beck I remained unaffected by demolition and construction, OPG said.

“That was our biggest challenge,” said project leader Andre Friedmann. “In the end, we came up with an innovative solution – and that was to set up a barge in front of the station from which we could do all the demolition and reconstruction work.”

Due to the fast flowing and turbulent waters of the Niagara River, traditional methods of using spuds and tugboats to respectively anchor and move the barge was not practical. The large sectional barge, roughly 49 m long and 12 m wide, safely accommodates an 85-ton crawler crane and two 35.5-ton excavators, among other required equipment. A temporary mooring system including heavy cables and winches connected to anchor points on shore allows the barge to be shuttled along the entire length of the tailrace while providing a stable platform for workers.

This solution has allowed Beck I to keep producing clean power unhindered throughout the project and the station played a major role in OPG’s Niagara hydro operations achieving its highest electricity output in over 40 years in 2023, according to a release. “Were it not for this barge, the new deck would have taken significantly longer to construct and we likely would have had to shut down some generating units to accommodate the work,” said Friedmann.

This is just the latest project under way at OPG’s Sir Adam Beck hydro complex, which includes Sir Adam Beck I and II GS, as well as the Sir Adam Beck Pump GS. This April, OPG announced its Niagara hydro fleet, which includes the Sir Adam Beck complex, will soon be undergoing a multi-year refurbishment. Last November, OPG successfully completed a high-voltage line replacement at the Sir Adam Beck II GS, Ontario’s largest hydro station. And in 2022, Sir Adam Beck I GS completed the replacement of two historic generating units, the first full unit replacements in its long history.

All told, OPG’s Niagara hydro stations meet about 9% of Ontario’s energy needs each year.