| Alabama: | Huntsville Utilities
Mobile Gas Service
North Alabama Gas District
Wheeler Basin |
| Arizona: | Southwest Gas Corporation
Unisource Energy Services
|
| Arkansas: | Arkansas Oklahoma Gas
Black Hills Energy
CenterPoint Energy (Arkla) |
| California: | California Gas Transmission Co
Pacific Gas & Electric (PG&E)
San Diego Gas & Electric
South California Gas Company
|
| Colorado: | Atmos Energy
Black Hills Energy
Colorado Natural Gas
Colorado Springs Utilities
Xcel Energy (PSCO) |
| Georgia: | Liberty Utilities |
| Illinois: | Ameren (CIPS, CILCO, IP)
Jo Carroll Energy
MidAmerican Energy
Nicor
North Shore
Peoples Gas
Rock Energy Cooperative |
| Indiana: | Citizen's Gas
NIPSCO
Ohio Valley Gas
Sycamore Gas Company
Vectren
|
| Iowa: | Alliant
Black Hills Energy
MidAmerican Energy
Liberty Utilities |
| Kansas: | Atmos Energy
Kansas Gas Service
Black Hills Energy
Midwest Energy |
| Kentucky: | Atmos Energy
Columbia Gas
Delta Natural Gas Company
Duke Energy
Louisville Gas & Electric
|
| Louisiana: | CenterPoint Energy (Arkla)
CenterPoint Energy (Entex) |
| Michigan: | Consumers Energy
DTE Energy (MichCon)
Michigan Gas Utilities
SEMCO Energy Gas Company
Citizen's Gas Fuel Company |
| Minnesota: | CenterPoint Energy (MN Gas)
Minnesota Energy Resources
Xcel Energy
|
| Mississippi: | Atmos Energy
CenterPoint Energy (Entex)
|
| Missouri: | Ameren
Atmos Energy
Empire
Laclede Gas Company
Liberty Utilities
Missouri Gas Energy
Southern Missouri Gas
Summit Natural Gas
|
| Montana: | Northwestern Energy |
| Nebraska: | Black Hills Energy
MidAmerican Energy
Northwestern Energy
|
|
Nevada: | Southwest Gas |
| New Mexico: | New Mexico Gas Company |
| North Carolina: | Piedmont Natural Gas Company
PSNC |
|
Ohio: | Columbia Gas
Dominion East Ohio
Dominion West Ohio
Duke Energy
Vectren Energy |
| Oklahoma: | Arkansas Oklahoma Gas
CenterPoint Energy (Arkla)
Oklahoma Natural Gas |
| South Carolina: | Piedmont Natural Gas Company |
| South Dakota: | MidAmerican Energy
Northwestern Energy |
| Tennessee: | Atmos Mid-State
Chattanooga Gas Company
Memphis, Light, Gas & Water
Piedmont Natural Gas Company
|
| Texas: | Atmos Energy
Atmos West Texas
CenterPoint Energy (Entex)
Texas Gas Services
WesTex Energy LLC
|
| Utah: | Questar Gas Company |
|
Virginia: | Roanoke Gas Company |
| Wisconsin | Alliant
Antigo City Gas
Madison Gas & Electric
Midwest Natural Gas
St. Croix Gas
Superior Water, Light & Power
WE-Energies
Wisconsin Public Service
Xcel Energy |
| Wyoming: | Black Hills Energy |
