Michigan Thumb Loop Transmission Line

A map from ITC, the developers of the project.

Stated Purpose:

The Thumb Loop project provides a much-needed high capacity transmission line designed to meet the maximum wind potential of the Thumb Loop region. Located in the region found to have the highest wind development potential in Michigan, this project is capable of supporting more than 2,800 turbines and 5,000 megawatts of renewable energy capacity.

As part of the MISO MVP portfolio, this line will be subject to regional cost allocation. In addition to creating new opportunity for wind development, this transmission project will also help reduce congestion, improve system reliability, and facilitate wholesale market competition.

Line Capacity:

345 kV

Route Description:

The line will be built in two phases and run 140 miles. The first phase passes through Sebewaing, Brookfield, Winsor, Oliver, Colfax, Verona, and Sigel townships, with scheduled completion in 2013. The second phase will extend from Sigel Township through Paris Township and into Sanilac and St, Clair counties, and is expected to be done by 2015.

Development Timeline:

The Thumb Loop project will be constructed in stages. ITC anticipates that the first segment, the western side of the loop from Tuscola County to Huron County, went  into service as scheduled in 2013. Construction on this 62 mile phase, extending from the new Bauer substation in Tuscola Township to the new Rapson substation in Huron County, began in April 2012. Learn more about the construction process here.

Beginning in 2013, construction crews will build a second phase which stretches 22 miles from Greenwood Township to Wales Township in St. Clair county. Construction for the Sanilac County portion of the line will begin in 2014 and cover 39 miles.

The Bauer substation has already been completed, and the first segment of the line is in service, and the Rapson substation near Bad Axe has also begun construction. The project is moving on to phase 2, a portion of the project that will run from the Greenwood substation to a new substation that will be built by Wales township.

Proposed in response to a state-wide renewable portfolio standard, this work will allow new wind farms to come online, helping Michigan meet its Renewable Portfolio Standard (RPS) of 10% renewable energy by 2015.

Regulatory Process:

In February 2011, the Michigan Public Service Commission (MPSC) provided a siting certificate for the Thumb Loop, and the order is the final regulatory approval that is required for the project.

One county board voted to take no action in 2013 on releasing land to ITC for the project, requiring the state to release the property to the utility instead.


International Transmission Company (ITC)

Community Feedback:

Landowners with property that may be crossed by the Thumb Loop have expressed concern about how the lines will impact farms throughout the region. One particular issue is concern over how construction of the line would affect central pivot irrigation, which has increased in use over the past 25 years within Michigan's agriculturally rich thumb area.

Many communities, however, have shown support. Up to 86% of Michigan residents support upgrading the electric transmission system in order to lower utility bills. Over 76% of Michigan residents also favor expanding the electric transmission system to allow for greater access to wind energy.

This line is a tremendous boost to economic development needs in a rural region that relies heavily upon agriculture. This potential has been bolstered by ITC's efforts to include local contractors and create local jobs. The first phase of construction has created 70 direct employment jobs, including local contractors, vendors, and suppliers. As in the case of other transmission projects, as well as wind developments, the economy is further boosted through indirect employment opportunities: busier motels, restaurants, and gas stations, and a growing need for local services such as trucking, accounting and legal services.

Clean Energy Potential:

The Michigan Thumb Loop was designed in response to Michigan's Clean, Renewable, and Efficient Energy Act of 2008. This law sets a statewide Renewable Portfolio Standard (RPS), which mandates that 10% of the state's energy must come from renewable sources by 2015.

The Wind Energy Resource Zone Board studied and identified regions with the highest wind potential throughout the state. The study concluded that the state's Thumb area--called Region 4--displayed the highest potential for wind energy. However, this region's electrical grid did not have sufficient capacity for new wind resources. This project was developed as a response to this study and the need for new transmission to make wind energy development possible.

ITC submitted its plan for the Thumb Loop project, in order to provide additional transmission that would be needed to support future wind developments in that region. Designed to meet the minimum and maximum wind energy potential of the Thumb region, ITC plans to build extensions as needed in order to accommodate new wind developments.

As designed, the project will provide the infrastructure necessary to support more than 2,800 additional wind turbines and 5,000 megawatts of renewable energy capacity. Many wind energy developers are already planning new projects to connect to this line. For example, NextEra Energy has been approved to build 63 turbines in Gilford Township, while Consumers Energy is planning to develop a 150 MW wind farm in Akron and Columbia Townships.

Finally, the Thumb Loop project has allowed DTE Energy to close the doors of a coal-fired power plant operating in the region. Since the plant was built to support the Thumb region, as well as provide voltage control, the Thumb Loop project has rendered it redundant and unnecessary. This is an example of clean energy transmission enabling enough wind integration to make coal-fired power plants obsolete.

News Archive:

How new transmission is unlocking wind power's potential in Michigan's Thumb May 26, 2015

Transmission 'backbone' to bolster renewables in Michigan May 14, 2015

ITC completes Thumb Loop transmission line project in Michigan, US May 14, 2015

Thumb's giant energy loop is complete May 14, 2015

Thumb Loop is complete and carrying electricity May 13, 2015

Final phase of power loop nears completion November 14, 2014

ITC Holdings to complete West Michigan transmission line project by end of 2014 July 25, 2014

Thumb Loop takes another major step June 25, 2014

Company finishes buildinging power line in St. Clair County June 24, 2014

ITC power project coming to Sanilac April 7, 2014

Two Firsts: A Bay City Nature Preserve, and the High-Voltage Thumb Loop November 22, 2013

Thumb Loop moves ahead October 6, 2013

ITC Fires Up First Phase Of New Thumb Power Grid September 30, 3013

County keeps wind energy request up in the air April 25, 2013

110 MW Thumb Wind Park now online in Michigan December 23, 2012

Electric loop work entering Huron County November 8, 2012

Thumb Loop coming together November 3, 2012

ITC offers update on Thumb Loop for wind power October 30, 2012

Thumb Loop to connect turbines with electrical grid September 10, 2012

High-voltage lines going up in Thumb September 5, 2012

DTE to close Harbor Beach power plant July 12, 2012

ITC Transmission celebrates start of construction of Thumb Loop June 29, 2012

WJR, state listeners tune in to Bad Axe May 11, 2012

Thumb Loop begins in Tuscola Township April 3, 2012

ITC selects contractor for first phase of transmission line construction March 5, 2012

Thumb Loop will begin next month March 2, 2012

Poll: Michigan residents strongly support transmission upgrades February 24, 2012

DTE, ITC discuss Sigel farm issues January 12, 2012

New Michigan transmission line to multiply wind capacity January 10, 2012

ITC to undertake portions of MISO-approved MVP projects December 12, 2011

Michigan coalition calls energy surcharge a bad deal November 15, 2011

Battle over Transmission Lines in the Thumb June 17, 2011

ITC Discusses Right of Entry for Thumb Loop Project April 26, 2011

MPSC denies motion to stay Thumb Loop approval April 13, 2011

Concerns of Thumb Loop aired at planning meeting April 8, 2011

MPSC Approves Route for ITC Thumb Loop Project February 28, 2011

Shifting Winds- Farms in Michigan's Thumb in path of plans for powerline December 28, 2010

Transmission lines in farm fields concern November 18, 2010

Michigan Farm Bureau, Thumb Loop FAQ November 2010

Your Thoughts:

We all know that clean energy transmission is vitally important to our energy future. It brings economic opportunity to rural areas, enables wind development and improves the reliability of your grid. But to build it properly - to create projects that work best for you and your community - requires your knowledge and participation.  That's why we've created this database.

Is there a way we can improve? Any changes that will make this a better tool for you? Alternatively, do you have more questions about this line? Would you like to receive our email updates? Send me an email at johnathanh@cfra.org, and let us know.


Get the Newsletter