Design of the Tretheway Creek run-of-river power plant

To meet the rising demand for clean energy in British Columbia, Innergex Renewable Energy Inc., an independent power producer, entered into a 40-year power purchase agreement with BC Hydro in 2008. In 2013, this producer began construction of the Tretheway Creek power plant, which is located 50 km north of Harrison Hot Springs. The environmental and financial project constraints, however, were numerous, as the facilities were to be built on very uneven ground and over 260 m in altitude. The project took two years of work before being commissioned.

Our experts' solutions

From the start of this project, BBA experts worked in partnership with the client to identify the best technical solutions that would optimize costs and facilitate the construction of the Tretheway Creek power plant. BBA was therefore involved from the feasibility study phase to the detailed engineering in design-build mode.

The project had an expected power capacity of 21.2 MW and consisted of building 4.6 km of penstock, varying from 1.7 m to 2.1 m in diameter, coming from a power plant powered by two Pelton turbines with a nominal flow rate of 11.4 m³/s, a 263-metre hydraulic head and a tailrace.
- Consideration of natural obstacles during the design phase to reduce excavation costs and curb the environmental footprint
- Installation of soil restraint was used to minimize the use of concrete anchor blocks on the buried section of the penstock (4.4 km).
- Innovative building design, built on a 20 m x 50 m projection, in a rock excavation at the foot of a steep, 200 m slope.
- Optimization of the penstock pass over a 5 km territory of mountainous topography
- Optimization of 200 km of penstock installed on pedestals
- Mapping streams and potential landslides
- Project cost reduction of nearly $8M

- 81 GWh Annual production of 81 GWh of clean energy
- 21.2 MW Power capacity of 21.2 MW
- 2015 Power plant commissioning in 2015
- 2055 Expiry of power purchase agreement in 2055

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