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45 MW Kokish River Hydroelectric Project

45 MW Kokish River Hydroelectric Project

Client
Peter Kiewit Infrastructure Co. (EPC Contractor), Kwagis Power Limited Partnership (Owner)

Location
British Columbia, Canada

Highlights
  • Project optimization and successfully designing and constructing a low impact run-of-river hydroelectric project on a high value salmon river.
  • Intake model testing for hydraulic design and optimization of the weir, intakes, sluice gates, screens, and large vertical slot fishway.
  • Temporary diversion channel was designed at a relatively flat grade to maintain fish-friendly migration flows even under low flow conditions, while being able to convey the flood flow for the entire construction period.
  • Coanda (“shear-effect”) intake screens (believed to be the largest in the world for a hydro project) and Obermeyer crest gate to allow for the safe passage of both adult and juvenile salmon and steelhead trout downstream from the diversion weir.
  • A large vertical slot fish ladder to allow safe passage of adult salmon and steelhead trout to pass the diversion weir.
  • Large diameter penstock that is over 9.3 km in length and exposed to internal hydraulic transient pressures, logging road traffic, and external natural forces.
  • Tailrace channel and fish fence to prevent adult salmon and steelhead trout from entering the tailrace and to generate flow patterns to encourage fish to continue on their upstream migration.
Project Overview

The 45 MW Kokish River Hydroelectric Project is a run-of-river hydroelectric project located approximately 15 km east of Port McNeill, on the northeast coast of Vancouver Island, British Columbia, Canada. Preliminary design and permitting activities were initiated in 2007 and the project was submitted as part of a competitive bid process in BC Hydro’s 2008 Clean Power Call. The project was awarded an energy purchase agreement (EPA) in 2010, and detailed design began in 2012, with construction starting in May 2012 and ending in April 2014 when commercial operation was achieved.

Project Role

As the lead design engineer, Knight Piésold worked closely with owner Kwagis Power Limited Partnership (Brookfield Renewable Energy Group and ‘Namgis First Nation) and EPC contractor Peter Kiewit Infrastructure Co. to develop innovative and cost-effective solutions that were able to meet the stringent permitting requirements.

Knight Piésold’s team was involved throughout project development and was responsible for project optimization, permitting assistance, and preliminary engineering before completing the detailed design. Other key project participants included Northwest Hydraulic Consultants for intake scale model testing and Rockwell Automation for the design of electrical components and control system. Ecofish Research also assisted with the permitting and fisheries aspects of the project.

The project incorporates an intake that diverts a portion of river flows from the Kokish River through a 9.3-km-long penstock into a surface powerhouse located adjacent to the lower reach of the river, where power is generated with four Pelton turbine-generating units from the diverted generation flow prior to being returned to the river. The project is interconnected to BC Hydro’s transmission system through a 138 kV transmission line and interconnection substation to the BC Hydro grid. Access to the hydroelectric project site was facilitated by existing public roads and forestry roads in the Kokish River valley.

Awards
  • Award of Excellence, Natural Resources, Mining, Industry & Energy Category, 2015 Canadian Consulting Engineering Awards
  • Award of Merit, Energy & Industry Category, 2015 ACEC-BC Awards for Engineering Excellence