Ontario Power Generation (OPG) has launched a 16-year overhaul of the 1045MW R.H. Saunders Generating Station, the second-largest hydroelectric project in Ontario, Canada. 

The project began in January, with the first of the station’s 16 units, G9, now fully disassembled, with refurbishment set to be completed by early 2024. The overhauls of the rest of the station’s units will occur each subsequent year until the project wraps up by around 2039.

The R.H. Saunders GS is situated on the St. Lawrence River and is part of the larger Moses-Saunders Power Dam shared with the US. It has played a significant role in providing baseload generation for Ontario for 65 years. The station was last overhauled in the 1990s to early 2000s. The current project is part of OPG's overall commitment to invest and revamp turbine-generator units across its hydroelectric fleet.

The overhaul of each unit will involve hoisting out and replacing the massive, 62-tonne turbine runner. The old runners will be replaced with newer, more efficient designs that will require less water to generate power. Another priority will be replacing the round throat ring liner, an embedded part that the turbine runner spins inside of, with a more adjustable design to deal with Alkali Aggregate Reactivity. 

Each overhaul will also involve installing new servo motors and thrust bearings, setting up new electrical systems, and completing a lot of machining, welding, and painting of the various generator and turbine components.

"We expect a lot of learning to take place on this first unit overhaul, which we will carry over to each subsequent unit," said Mike Woodcock, Senior Manager of Maintenance and Production. "When it's all said and done, the station will be performing much more efficiently, making clean electricity from less water. And the project will have created significant economic benefits for Ontario and the local community."

Several experienced OPG employees who were around for the last overhauls are helping to mentor workers while sharing their knowledge and expertise. The project is also looking outside for help through contractors, original equipment manufacturers, and local businesses. "We've reached out to people from the Cornwall community for support, hiring local vendors and suppliers, including two Cornwall-based metal fabricators," said Codie Lonsberry, Project Site Manager at R.H. Saunders.

An Indigenous company based out of Desoronto has been contracted to sandblast, repair, and repaint several working platforms needed for the G9 overhaul, which supports OPG's Reconciliation Action Plan goals. "We are striving to utilize as many local companies as we can particularly from Cornwall and across the province," said Lonsberry.

Images: Top – The turbine runner is pulled up from R.H. Saunders GS's G9 unit; The team in front of the runner assembly after it was lifted from the G9 unit. Courtesy Ontario Power Generation.