What BC Hydro's doing with its 80-year-old dam and powerhouse
MISSION – A light bulb in the powerhouse at Ruskin Dam has burned for more than 80 years – helping employees monitor the DC power system used to operate plant controls at one of B.C.'s oldest dams. It's also a fitting symbol for the legacy of clean electrical power left to us by previous generations of British Columbians.
But time takes its toll on even the hardiest structures and technologies. That wear and tear is particularly evident here at the Ruskin Dam where key components of the dam are vulnerable to the very worst that nature can throw at it.
"The right abutment and upper part of the dam where the concrete piers holding the spillway gates don't have sufficient strength to meet our seismic criteria for a modern hydroelectric dam," says BC Hydro commercial manager Dean Cardno.
Simply put, BC Hydro has concerns about how the facility, originally built in the 1930's, would perform in a major earthquake.
As B.C. continues to grow, so has our need for clean electricity. BC Hydro's goal is to manage that growth through conservation, while renewing infrastructure to meet the needs of future generations. This includes the Ruskin Dam, where major upgrades will ensure the dam continues to operate safely and produce clean, reliable energy for the next 50 years.
A seismic upgrade and more
Back in 1930, a seepage cutoff wall built upstream of the dam on the right abutment worked "much like the liner in your swimming pool by keeping the water in," says Hydro engineer Nick Vanderkwaak. The existing cutoff wall, being seismically deficient, will be replaced by a specially designed in-ground barrier wall will reinforce the right bank to control water seepage.
"There are specialized techniques in creating such a wall," he adds. "It will extend from the surface of the right bank right down into bedrock so when it hardens it will be impervious."
The final phase will see the relocation of the switchyard to the left bank hill.
But what excites Vanderkwaak most are the Ruskin Dam's three 35-megawatt turbine engines – two built in 1930, one added in 1950. Like the powerhouse's 80-year old light bulb, the turbines "have proven themselves to be of good design and long serviceability," he says. Now, they're tired and running inefficiently.
The solution, says Vanderkwaak: retain those parts of the turbines and generators that continue to be serviceable, like the rotors and bearings ("These are really remarkable components, a tribute to their original design.") and replace those that don't work so well – like the stator core and windings.
The object is to improve Ruskin Powerhouse performance.
"We've measured 85 and 86 per cent efficiency in the existing turbines" says Vanderkwaak." By replacing most of their components we hope to get them up to as high as 94 per cent. After the upgrade project is complete, Ruskin will provide enough electricity for over 33,000 homes."
Replacement of the three generating units will be phased in, one at a time, Vanderkwaak adds, to allow the facility to continue to generate electricity throughout the project.
Benefits for people and the environment
Changes at the Ruskin Dam are not just about concrete and steel; they're about people, people who live in the District of Mission and who depend upon important recreational activities near the dam, such as camping, picnicking, hiking and fishing.
BC Hydro already provides parking, washrooms or pit toilets, and picnic tables to support those activities. The Ruskin Dam and Powerhouse Upgrade project will provide additional environmental benefits including improved flow continuity to protect downstream fish and wildlife habitat.
The project will also generate approximately 1,050 person years of employment during construction. No one is more excited about that than Mission Mayor James Atebe.
"I'm excited by the economic activity that will emanate from the investment in our community," says Atebe. "It complements our community forest and the recreational opportunities that we're trying to create here. But I'm even more excited by the opportunities for small business both locally and regionally."