Rehabilitation and Repair

Out with the old, in with the new: Otto Holden station gets new bearings

The 243 MW Otto Holden Generating Station on the Ottawa River is swapping out old technology as part of Ontario Power Generation’s investment to refurbish eight hydroelectric generating stations in eastern Ontario.
Out with the old, in with the new: Otto Holden station gets new bearings
ThorPlas-Blue installed in Unit 7 turbine at Otto Holden Generating Station (courtesy: Thordon Bearings Inc)

Thordon Bearings is supplying multiple sets of grease-free bearings to completely replace old
technology at the 243 MW Otto Holden Generating Station on the Ottawa River in Ontario, Canada.

In June, the government of Ontario announced support for Ontario Power Generation’s (OPG) roughly $1 billion investment to refurbish eight hydroelectric generating stations in eastern Ontario, including Otto Holden Generating Station. This infrastructure program will secure 1,617 MW of clean electricity generation, helping to meet increasing demand from electrification and fueling the province’s growth. OPG has identified significant untapped hydroelectric generation opportunities; in the northern rivers of Ontario alone, there are about 4,000 MW of potential power.

“The hydropower market is growing globally due in part to the increasing demand for renewable energy,” explained Ryan Edmonds, business development manager for hydro and industrial at Thordon Bearings. “Hydropower is a clean, secure, domestic source of electricity.”

Andritz Hydro was contracted to undertake the mid-life refurbishment of the Otto Holden station’s turbines on behalf of OPG. Two of the station’s eight units have been fitted with Thordon’s ThorPlas-Blue and Thorseal products, via local distributors RMH Industries in Quebec and Millstream Engineering in Ontario. Unit 7 was refurbished in 2022, unit 5 in 2023, and unit 8 is next with installation expected in Q4 this year, according to Andritz. By 2029, all eight of the station’s units will have been refurbished.

What’s that you say, dear reader? You crave more nitty and gritty information about retrofitting bearings?

Each retrofit involved 262 bearings per turbine, including wicket gate bearings and seals, Thorseal
linkage bearings, Thordon SXL operating ring wear pads, and servo motor bearings and seals, said Thordon. The bearings have high-end edge loading performance and range from about 100 to
300 mm (4-12 in) outside diameter.

The servomotors are constructed entirely by RMH Industries, one of the company’s specialties honed over the past 50 years. Thordon’s bearing and sealing solutions eliminate the need for regular greasing, thus reducing maintenance costs and avoiding contamination of rivers.

Thordon’s wicket gate, operating mechanism and linkage bearings operate wet or dry and are self-lubricating to ensure performance in limited-motion applications, according to a release. There is no galling from edge loading caused by minor misalignments or gate deflections. The bearing material, ThorPlas-Blue, is a homogeneous, self-lubricating engineered thermoplastic capable of withstanding operating pressures up to 45 MPa (6,527 psi).

Thordon’s Thorseals are made of a proprietary elastomer with no shelf life or degradation of
properties over time. Thorseals are available in a range of standard sizes or can be quickly
machined to custom size requirements up to 1.5 m (60 in) in diameter.

“It is critical to get accurate measurements of the shaft and housing dimensions before final
machining of the ThorPlas-Blue bearings so that they can be sized correctly for proper fit and
clearance,” cautions commercial director at Millstream Engineering, Greg Auger. “During installation, care must be taken to press-fit the bearings to prevent damage, and then they must be protected from risk of damage while other overhaul work continues. Careful measuring of the installed dimensions will help verify that all the large components will assemble correctly.”

Millstream Engineering will continue to provide local support to OPG at its facilities across Ontario. Auger says there is a big push under way for overhauling and modernizing hydropower facilities across Canada, and the Otto Holden station is one of many to be rehabilitated over the next decade.