Project Overview
MATL Line Quick Facts:
- Length of the line: approximately 214 miles (345 kilometers)
- Voltage: 230 kV (stepped up to 240 kV at Lethbridge to match the voltage of the Alberta transmission network)
- Transmission capacity: 300 MW bi-directional
- Conductor: Falcon 1590 kcmil ACSR
- Number of structures: Approximately 1,700
- In service: Mid 2010
The Montana Alberta Tie Ltd. (MATL) line is a 300-megawatt (MW), 230-kilovolt (KV) electrical transmission line allowing the movement of power between Alberta and Montana.
The 214-mile (345 kilometer) line will tie into the Alberta grid at a new substation located nine miles (15 kilometers) northeast of the city of Lethbridge. The line will run approximately 81 miles (130 kilometers) south to the US/Canada border at a point west of the Sweetgrass/Coutts border crossing. From there, it will run a further 133 miles (215 kilometers) south to terminate at NorthWestern Energy’s Great Falls substation which is located just north of Great Falls, Montana.
An additional substation will be built at approximately the half-way point of the transmission line, just north of the Marias River near Cut Bank, Montana. This substation will provide a mid-point disconnect to the line and power factor support as well as a convenient interconnection point for wind farms in the area.
The MATL transmission line will be supported by two types of structures: steel mono-poles and H-frames made principally of wood. H-frame construction provides the best balance between structural integrity and physical and visual intrusion. Where it is desirable to minimize the footprint of the transmission line, for example to avoid excessive impact on farming operations, mono-poles are employed.
Dimensions vary along the line depending on surrounding features and topography, but these structures are generally 60 to 100 feet (18 to 30 meters) high. Mono-poles in irrigated areas average 459 feet (140 meters) apart. H-frames and monopoles in non-irrigated areas average 787 feet (240 meters) apart.
The conductor, i.e. the conduit for transmitting the electrical power, is Falcon 1590 kcmil ACSR measuring 1.5 inches (3.81 cm) in diameter. ACSR stands for “aluminum conductor, steel reinforced.” It comprises 54 strands of high-grade aluminum wire weaved over 19 stainless steel strands to form a single cable. The aluminum is the current-carrying conductor while the steel provides the tensile strength.
Montana Alberta Tie Ltd. is headquartered in Calgary, Alberta and is wholly owned by Toronto based Tonbridge Power Inc., which is listed on the TSX Venture Exchange under the symbol TBZ.