History of Guardian
Guardian Pipeline is a key natural gas system serving the Upper Midwest. Originally built in 2002 to transport gas from the major Chicago hubs into other Midwest markets, it has a strong history of safely and reliably serving these growing regions. Guardian has maintained a strong operational reputation complimented by its relatively modern infrastructure and integrity management practices.
A major second-phase expansion was completed in 2008, extending the pipeline north by over 100 miles towards Eastern Wisconsin. This added reliable service to utilities in those growing population centers.
DT Midstream acquired Guardian Pipeline on December 31st, 2024. We are proposing the third expansion of the Guardian Pipeline, which is called the G3 Expansion Project.
G3 Expansion Project
The G3 Expansion Project will expand Guardian Pipeline’s existing natural gas system to meet growing regional demand, enhance energy reliability, and support the Midwest’s transition toward cleaner, dispatchable energy resources. The project includes approximately 68 miles of new 36-inch pipeline looping, new compressor additions at the Joliet Station, a new compressor station in Dodge County, Wisconsin, and a new meter site in Fon du Lac County, Wisconsin.
The expansion will add approximately 537,000 Dth/d of new firm transportation capacity, targeted for a November 2028 in‑service date, pending regulatory approvals. Following two binding Open Seasons in 2025, Guardian secured long‑term commitments for the full project capacity from five unaffiliated shippers.
Independent market analysis confirms strong and growing demand for additional natural gas supplies across the electric generation and LDC sectors. Guardian’s system is strategically positioned to access diverse supply basins— including the Permian, Rockies, Gulf Coast, Appalachia, Western Canada, and Upper Midwest storage—ensuring reliable service for shippers. Overall, the G3 Expansion Project provides critical infrastructure to support economic growth, energy reliability, and the region’s evolving energy mix, delivering measurable benefits to shippers, utilities, power generators, and consumers.
Benefits & Facts
Economic Impact
DT Midstream is investing in an expansion of its Guardian Pipeline system through a series of natural gas transmission and related facility projects. These investments include pipeline looping, compression additions and upgrades, meter-and-regulation facilities, and associated engineering and construction activities designed to expand transmission capacity, enhance reliability, and support growing natural gas demand across the Midwest.
Over the 2025-2028 period, these investments are expected to generate $1.58 billion in economic output in Illinois, and $181 million in Wisconsin. During the same period in these states combined, approximately $176 million in local, state, and federal tax revenue.
Beyond measurable economic impacts, DT Midstream’s investments enhance regional energy reliability, expand transmission capacity, and support long-term economic growth across the Midwest.
Project Timeline
Public Information Session
June 2026
FERC Application Filing
July 2026
Requested Certificate Issuance
June 2027
Proposed Construction
September 2027
Target In-Service
November 2028
Meeting the Needs of Midwest Energy Customers
Anchored by the needs of 5 utilities in the upper Midwest, G3 will add needed capacity to the Guardian Pipeline, which provides dependable natural gas for these markets.
Natural gas is essential for heat and electricity throughout the region. G3 will help ensure a continued reliable supply of natural gas to meet the growing heat and electricity demands in northern Illinois and Wisconsin.
Dependable Energy, Local Jobs, and Stronger Communities
G3 is designed to strengthen a dependable supply of American natural gas—directly helping prevent energy shortages for families and businesses across the growing Midwest.
G3 will generate significant new tax revenue for federal, state, and local governments during construction and for decades of operation. Just like the taxes already paid by Guardian Pipeline, these additional dollars will directly support local schools, fire and police departments, roads, and other vital community services.
During construction, the project will create hundreds of good-paying jobs for skilled tradespeople, welders, truck drivers, equipment operators, and many others. These workers and their families will spend their wages at local stores, restaurants, and businesses, creating a powerful ripple effect that sustains thousands more jobs throughout the region.
Committed to Community Engagement at Every Step
DT Midstream is committed to open and ongoing communication with the community throughout this project. From the earliest planning stages, we have actively sought input from local leaders, elected officials, economic development groups, emergency responders, and community organizations.
At the same time, our land team has been meeting regularly with residents and landowners to discuss potential routes and address concerns.
As the project moves forward, we will continue these conversations across the region and share regular updates through multiple channels — including community meetings, mailings, and this project website — so everyone has ample opportunity to stay informed and provide feedback.
Frequently Asked Questions
DT Midstream is the owner, operator and developer of natural gas interstate and intrastate pipelines, storage and gathering systems, and compression facilities. The company transports clean natural gas for utilities, power plants, large industrial customers and energy producers and serves markets in Southern, Northeastern and Midwestern United States and Canada. DT Midstream is an industry leader in safety, community engagement, volunteerism and philanthropy.
DT Midstream owns more than 2,200 miles of FERC-regulated interstate natural gas pipelines; owns and operates approximately 700 miles of gathering pipelines; owns and operates gas storage assets with capacity of 94 Bcf; and owns and operates more than 800 miles of gathering pipelines throughout American natural gas supply basins.
The project is a proposed 68-mile pipeline looping and compression expansion of the existing 263-mile Guardian pipeline.
The project will meet significant growing market demand for additional natural gas deliveries, strengthen electric grid reliability, improve resilience during extreme weather, and maintain access to affordable energy in the upper Midwest. It will also complement renewable generation as coal‑fired units retire and local utilities transition toward cleaner natural gas and renewable resources.
The project is generally located in rural farming regions of northern Illinois, southern Wisconsin and includes a new compressor station along the pipeline’s route in Wisconsin. The new looped natural gas pipeline will stay as close as reasonably acceptable to the existing Guardian easement and right-of-ways.
The project’s total capital investment will be approximately $850 to $930 million and will support up to 780 construction related jobs.
The project will generate new tax revenue for federal, state, and local governments during construction and operation. Those tax dollars will directly support local schools, fire and police departments, roads, and other vital community services.
The G3 Expansion Project will also support hundreds of good-paying construction jobs for skilled tradespeople. Wages spent at local stores, restaurants, and businesses, sustaining jobs in the region.
DT Midstream and the G3 Expansion Project are committed to open and ongoing communication with the community throughout project. This includes actively seeking input from local leaders, elected officials, economic development groups, emergency responders, and community organizations.
The project’s team has maintained an open dialogue across the region, sharing regular updates through community meetings, mailings, and project website. Communication provides stakeholders the opportunity to stay informed and provide feedback.
- FERC Application Filing: June 2026
- Requested Certificate Issuance Certificate: June 2027
- Proposed Construction: July 2027
- Target in-service: November 2028
The following federal entities provide regulatory oversight of the project: U.S. Federal Energy Regulatory Commission (FERC), U.S. Environmental Protection Agency (EPA), United States Pipelines Safety Administration (PHMSA) among others.
DT Midstream and the G3 Expansion Project will closely follow FERC’s process to meet or exceed all requirements while ongoing work with local officials should ensure a smooth construction and commissioning process.
The existing Guardian Pipeline is already electronically monitored 24/7/365, and by field operations personnel in the region. The G3 Expansion Project facilities will be a part of those existing operations. The design, maintenance, and operations of the pipeline adhere to strict rules and regulations administered by federal government agencies.
Ways to Reach Us
G3 Expansion Project
Toll Free: (833) 575-4049
Email: outreach@dtmidstream.com
Write to Us
DT Midstream
500 Woodward Ave., Suite 2900
Detroit, MI 48226
Media Relations
Phone: (313) 774-0690
Email: media@dtmidstream.com
Vendor Supply Chain
Vendor/Supply Chain Inquiries:
Jennifer Carver – Director, Corporate Services
jennifer.carver@dtmidstream.com
Phone: (313) 774-3174