Keeyask Generating Station

Background

The Keeyask Generating Station (GS) was initially identified by Manitoba Hydro as a potential hydroelectric development as part of the northern system expansion work that began in 1966. The site has been considered one of the future hydroelectric development options since that time. It was proposed to be committed as part of the business case submitted in the most recent regulatory review called the Needs For and Alternatives To (NFAT) process that was concluded in the summer of 2014. Regulatory approvals to start the construction of the Keeyask Generation Project (GP) and the Keeyask Transmission Project were received in July 2014. The Keeyask GS is scheduled to be in-service for 2019 to fulfil new export sales agreements with Minnesota Power and Wisconsin Public Service and continued load growth in Manitoba.

The Keeyask GP is a collaborative effort between Manitoba Hydro and four Manitoba First Nations, working together as the Keeyask Hydropower Limited Partnership (KHLP). The four partner first nations include, Tataskweyak Cree Nation (TCN), War Lake First Nation (WLFN) (acting as the Cree Nation Partners), York Factory First Nation (YFFN) and Fox Lake Cree Nation (FLCN). Manitoba Hydro will operate the Keeyask GP as part of the Manitoba power grid on behalf of the KHLP. Manitoba Hydro will own and operate the Keeyask Transmission Project.

Location

The Keeyask (Cree for gull) GS will be located at Gull Rapids, immediately upstream of Stephens Lake on the lower Nelson River. The Keeyask GS is located:

• 30 km (19 mi) west of the Town of Gillam;
• 35 km (22 mi) upstream of the existing Kettle Generating Station;
• 60 km (37 mi) northeast of Split Lake;
• 180 km (112 mi) northeast of the City of Thompson; and
• 730 km (454 mi) north of the City of Winnipeg.

The generation and infrastructure projects are entirely within the Split Lake Resource Management Area with the transmission project extending into the Fox Lake Resource Management Area.

Project Components

Principal Structures

The Keeyask GS consists of a close-coupled intake/powerhouse with seven units, three dams, two dykes and a gated seven-bay spillway (Figure 1). The spillway is required to manage diverted flows when the project is being constructed and to manage surplus water flows once it goes into production. The dams and dykes will contain the reservoir created upstream of the principal structures.

The principal structures will stretch 2.7 km (1.7 mi) across the Nelson River, with the dykes extending 11.5 km (7.2 mi) on the north shore and 11.2 km (7.0 mi) on the south. The reservoir is predicted to expand by 7 to 8 km2 (2.7 to 3.1 mi2) due to shoreline erosion and peatland disintegration over the first 30 years of operations.

file:Keeyask 1.jpg|thumb|center|upright=3.0|Figure 1: Computer Rendering of Keeyask Generating Station Principal Structures

Project Data

• Turbine Generator Units:
  • Type: 7 vertical shaft fixed blade propeller turbines
  • Capacity: 695 MW
• Powerhouse:
  • Length: 211.74 m (694.7 ft)
  • Waterfall drop (head): approximately 18 m (59 ft)
  • Discharge capacity: 4,100 m3/s (144,790 ft3/s)
• Main Dams:
  • Length - North dam: 100 m (328 ft), Central dam: 1,600 m (5,249 ft), South dam: 565 m (1,854 ft)
  • Maximum height: 28 m (91.9 ft) (Central dam)
• Spillway:
  • Number of bays: 7
  • Length (7 bays): 119.0 m (390 ft)
  • Discharge capacity: 11,315 m3/s (399,585 ft3/s)
• Reservoir/Forebay Elevation:
  • Full supply level: 159.00 m (521.65 ft)
  • Normal minimum operating forebay elevation: 158.00 m (519.37 ft)
  • Flooded area: 45 km2 (17.4 mi2) may gradually increase due to erosion

Supporting Infrastructure

Permanent supporting infrastructure includes a permanent 25 km (15.5 mi) north access gravel road, a permanent 21.7 mile (35 km) south access gravel road, a transmission tower spur, a communications tower, a placement area for excavated materials, remnants of some cofferdams and rock groins, boat launches, a portage, barge landings, public safety and security measures, and some haul roads and borrow areas required for operations. Once the generating station is completed, the north and south access roads will be connected across the principal structures and integrated into the provincial highway network.

Transmission Components

Construction Power

A new transmission line in a single right-of-way will be constructed from an existing 138 kV transmission line (KN36) 22 km (13.7 mi) south of Gull Rapids. The line will terminate at a new substation north of the Keeyask GS and the Nelson River to provide construction power (Figure 3). The line and substation will be retained to provide a backup source of offsite power to the generating station once it goes into operation.

Generation Outlet Transmission

Four 3.4 km (2.1 mi) transmission lines will transmit the power from the generating station to a new Keeyask switching station south of the generating station (Figure 3). Three 35 km (21.7 mi) transmission lines in a single route will transmit power from the switching station to the Radisson Converter Station, where the power will enter Manitoba Hydro’s integrated power system. One of the three lines will be built prior to the other two to serve as a back-up source of construction power. Transmission station upgrades to terminate the three lines will also be required at the Radisson Converter Station.

file:Keeyask 3.jpg|thumb|center|upright=3.0|Figure 3: Keeyask Generation Outlet Lines

Construction

Principle Structures

Construction began in 2012 with the KIP. Regulatory approvals to start the construction of the Keeyask GP and the Keeyask Transmission Project were received in July 2014. The Keeyask GP will take 11 years to construct. The construction phase will conclude with decommissioning of infrastructure no longer required for operations and with rehabilitation of the site in 2022. The first of seven generating units will begin producing power in 2019, with all seven units producing power by 2020. The final three years of construction will overlap with the first three years of operation.

Materials required for the construction of the Keeyask GS will include impervious fill, granular fill, rockfill, riprap and concrete aggregates. Design and construction will maximize the use of rock obtained from the excavations required for the construction of the Principal Structures, minimizing the amount of material required to be obtained from quarries and borrow areas. Except for the construction of the South Dyke, the sources of materials required for the construction of the generating station facilities will generally be obtained within 10 km (6.2 mi) of the facilities structures. Granular material for the South Dyke will be obtained from sources having a round trip haul distance up to 42 km (26.1 miles).

Construction Infrastructure

Temporary supporting infrastructure includes a main camp, work areas, water, and waste water treatment facilities, ice boom, boat launches, cofferdams, rock groin, causeways, and safety and security facilities, as well as haul roads and borrow areas not required for operations.

During the first year of construction, power is provided by diesel generators. During the second year of construction, a permanent transmission line from KN36 will be in place to provide the primary source of construction power.

The Gillam Redevelopment and Expansion Program is also being undertaken to refurbish and enhance that community’s infrastructure and services to meet the needs of the existing and expanding population.

Mitigation Measures

The hydroelectric potential of the lower Nelson River has undergone decades of study, originally by the Governments of Canada and Manitoba and later by Manitoba Hydro. The early studies examined the feasibility of multiple development options. More recently, the local Cree Nations have taken an active role in planning the Keeyask Generation Project, assessing the potential effects and developing mitigation measures. Other First Nations, the Manitoba Métis Federation and the public have also been engaged through bilateral meetings, public involvement programs and self-directed studies. Through this process, Manitoba Hydro is able to avoid, reduce and mitigate many potential adverse effects while enhancing potential benefits.

The following examples illustrate potential adverse effects that have been avoided, reduced or mitigated through the planning and assessment process:

• by reducing the generating station from 1,150 to 695 MW, the initial flooded area was reduced from 180 km2 to 45 km2 (69.5 mi2 to 17.4 mi2) (Figure 2), which avoids flooding on Split Lake where TCN and YFFN have their home reserves;
• the normal operating range of the Keeyask GS will be 1.0 m (3.3 ft), very small for a major generating station in Manitoba, Canada or internationally;
• the north access road was routed away from sensitive sites, such as caribou calving habitat and regionally rare habitat types;
• turbines that minimize fish mortality were selected for the project, over 90% of the fish up to 500 mm (1.64 ft) in length passing downstream through the generating station are expected to survive.
• most of the reservoir will be cleared before flooding;

important fish habitat, nesting sites for birds, and wetlands will be developed; 

• new caribou calving habitat on islands in the reservoir will offset most losses caused by the project; and
• appreciating that the partnership is among many entities with ongoing roles respecting caribou in the region, the partnership is working to develop a process to coordinate its activities with government authorities, caribou management boards and resource management boards.

file:Keeyask 2.jpg|thumb|center|upright=3.0|Figure 2: Alternative Keeyask Development Options

Operation

Transportation: Once the generating station is completed, the north and south access roads will be connected across the principal structures and integrated into the provincial highway network as a new PR 280 route. Once PR 280 is re-routed over the generating station, travel from the Town of Gillam to the community of Split Lake and City of Thompson will be reduced by 53 km (32.9 mi).

Workforce: The station will have approximately 40 staff that will serve operational and maintenance (electrical, mechanical, and utility), support (administration, stores) and supervisory roles. The personnel will be located on site during normal business hours, seven days per week. They will likely work similar schedules to other generating stations in Manitoba Hydro’s system and live in the surrounding area. Details have not been finalized at this time. Support and technical services will also be located in the nearby Town of Gillam.

Water Regime: The Keeyask GS will be operated as a run-of-river generating station. For more information on its operation and its effects on the water regime, see the Keeyask GP Environmental Impact Statement (EIS).

Licences: On July 2, 2014 the Province of Manitoba issued an Environment Act licence (No. 3107) and a Water Power Act licence on July 5, 2014 for the Keeyask GP proposed by the KHLP. For further information on the Water Power Licence, see the Manitoba Government Water Power Licensing website at: http://www.gov.mb.ca/waterstewardship/licensing/water_power_licensing.html.