Project description

The Manitoba–Minnesota Transmission Project includes construction of a 500-kilovolt AC transmission line in southeastern Manitoba and upgrades to associated converter stations at Dorsey, Riel, and Glenboro. The transmission line:

  • starts at the Dorsey converter station (located near Rosser, northwest of Winnipeg);
  • travels south around Winnipeg and passes near the Riel Station (east of the city) along what is known as the Southern Loop corridor;
  • continues south to the Manitoba–Minnesota border;
  • connects to the Great Northern Transmission Line.

The Great Northern Transmission Line was constructed by Minnesota Power. It terminates at Iron Range Station located northwest of Duluth, Minnesota. The projected in-service date for the Manitoba–Minnesota Transmission Project is mid-2020. The budget as of March 2020 is estimated at $490 million.

Right-of-way and tower design

Two types of towers for the project: a tall, thinner guyed steel structure, and a shorter, wider self-supporting tower.

Towers types: guyed steel structure (left), self-supporting steel lattice (right).
Enlarge image.

The right-of-way required for the transmission line depends on the design of the tower structures. Towers are mostly 2 types (guyed and self-supported) and typically range in height from 40 to 60 metres. Spacing between towers is 400 to 500 metres apart on average.

  • Self-supporting steel lattice towers are mostly used in cultivated crop lands (agricultural areas), to minimize impact on agricultural operations. Right-of-way width is 80 metres for these towers.
  • Guyed steel towers are mostly used in non-cultivated lands. Right-of-way width is 100 metres for these towers.

Conductor-to-ground distances at maximum loading meets the Canadian Standards Association standard for minimum ground clearance of transmission lines

Station modifications

For the transmission line to be compatible with the existing system, modifications are being made to both Riel and Dorsey converter stations.

Although distant from the proposed transmission line, modifications to Glenboro Station are also being made, including extending the current switch yard and installing additional equipment. Several towers on existing lines were moved in the station expansion (PDF, 2 MB).

Environmental assessment & route selection

An Environmental Impact Statement (EIS) was completed and submitted for regulatory review. Feedback received through the engagement processes enhanced the environmental assessment work and assisted in determining the final placement of the transmission line.

Route selection

Input received through the engagement and environmental assessment processes assisted in determining the final preferred route.

We used a process based on the EPRI-GTC Overhead Electric Transmission Line Siting Methodology to assist us in determining the final preferred route.

Environmental assessment

The Environmental Impact Statement (EIS) was submitted to Manitoba Conservation and Climate (formerly Manitoba Sustainable Development) for review. Read more about regulatory requirements.

The project EIS included:

  • study area characterization through fieldwork and background investigation;
  • public and First Nation and Metis engagement to obtain feedback and input into route selection and the environmental assessment;
  • identification and assessment of potential environmental and socio-economic effects;
  • development of mitigation measures and monitoring plans;
  • development of an environmental protection program.

Schedule

  • Public notification of project: August 2013 (completed);
  • Round 1 engagement processes: October 2013 to February 2014 (completed);
  • Refined alternative routes determined: February 2014 (completed);
  • Round 2 engagement processes: March to December 2014 (completed);
  • Preferred route determined: December 2014 (completed);
  • Round 3 engagement processes: January to September 2015 (completed);
  • Regulatory submission: September 2015 (completed);
  • Regulatory review process: 2015 to 2019 (completed);
  • In-service date: 2020 (completed).

Progress

2019:

  • In August, the National Energy Board of Canada granted regulatory approval.
  • In collaboration with Indigenous communities, a pipe ceremony was conducted on the site of future construction to honour the land and the life around it. Indigenous engagement and direct involvement are a major part of the project.
  • Construction began very shortly after the pipe ceremony, beginning with clearing trees on the right of way, setting up work sites near key construction areas, and collecting necessary materials.
  • Foundation work and geotechnical assessments began in September.
  • Tower assembly began at the beginning of September.
  • A major storm hit the province of Manitoba in October, bringing heavy wet snow and freezing rain. Progress was temporarily impacted while we worked to restore power to thousands of customers and repair millions of dollars’ worth of damage to our electrical infrastructure.
  • Tower erection began shortly after the storm clean-up.
  • On December 5, 12, and 19, we moved three large autotransformers 132 km from the manufacturing plant in Winnipeg to their final destination at Riel converter station. These autotransformers are part of several upgrades to our system designed to handle increased load from MMTP.
  • December 19, the first stage of line stringing using a helicopter began. To do this, a skilled helicopter pilot flies a rope into pulleys onto towers. Once completed, the rope will be attached to a bigger, metal cable and pulled through the pulleys. Then, using the stronger line, three conductor lines (the actual power cables) are pulled through the pulleys to their final destination.

2020:

  • We continued to progress at an accelerated pace and made our in-service deadline of spring 2020.
  • The completed line was tied into our existing system and the Great Northern Transmission Line.