After over a century of service, a generator at Nelson's hydroelectric power plant has likely stopped spinning for good.
Nelson Hydro announced the G2 generator at its Bonnington facility has been shut down indefinitely after general manager Scott Spencer said cracks were discovered in its operating ring last October during an annual maintenance check.
Operating rings control the speed of the turbine connected to the generator. Nelson Hydro was installing a new control arm in the generator to replace the original component when it realized the operating ring could not be salvaged.
“It was probably at end of life 40 years ago and it was repaired then, and now the repair has failed," said Spencer. "So it did not feel like it would be safe for us to try to repair and knowing it could just crack or break in another location.”
The city-owned Bonnington facility has five generators, three of which are still operating.
The first, or G1, was there when the plant opened in 1907 but has been out of service since the late 1950s.
G2 has had a tumultuous history. It was installed in January 1910 and used on and off until 1974 when the Kootenay Canal was completed. The city resumed using G2 in 1984 for freshet generation and ahead of increased water rights granted in 1988. It was shut down yet again in 2001, and returned to service in 2003.
G3, built in 1929, is still in use during freshet or when one of the other generators requires maintenance. G4, constructed in 1949, and G5, added in 1995, operate year round.
Spencer said G2, G3 and G4 require an operator's manual controls when the units are started or stopped. A faulty operating ring is a safety risk to the staff as well as the other nearby generators.
Decreased freshet may make fixing the generator not worth the expense. The 2024 freshet lasted 26 days, a decrease of two days from 2023 and well down from 112 days in 2017, according to Nelson Hydro. Spencer said the company will evaluate the business case for a new or refurbished generator over the next year.
As for the now 118-year-old power plant, Spencer described the building as "a living museum" that still has a sound foundation even though the original concrete was only built to last about a century.
Nelson Hydro has committed $10 million in dam safety repairs over the next decade. The aging facility will need to be replaced at some point, but Spencer doesn't believe that will happen for some time yet.
“Is there going to be a point sometime in the future when it's no longer economically viable to continue to repair? It's kind of like your car. At some point you can't keep up with the repairs, and you can't afford to repair, it's cheaper to buy a new car."
