Tallgrass Development, LP (“Tallgrass”) announced today that it intends to pursue the development of a new natural gas pipeline, the Prairie State Pipeline, with ownership participation by Tallgrass and AGL Resources Inc. (“AGL”). Tallgrass and AGL (the “Sponsors”) also announced a non-binding open season (“Open Season”) for natural gas market participants to move gas from supply connections in central Illinois to the Chicago Market Center and points in between (the “Project”). The Project is accepting non-binding bids for long-term firm transportation capacity on the Project.

Prairie State Pipeline is expected to have a total capacity between 1.2 Bcf/d and 1.5 Bcf/d and has already received an expression of interest for a commitment of 400 MMcf/d. Prairie State Pipeline will provide additional supply diversity and access to the Illinois and Midwest markets, while increasing reliability through new infrastructure construction.

When complete, Prairie State Pipeline is expected to consist of nearly 140 miles of large diameter pipeline running in a generally north-south orientation, to connect interstate pipelines in Douglas County, Ill., to gas distribution systems, natural gas storage fields and interstate pipeline companies in the Chicago Market Center. Prairie State Pipeline expects to provide unique access to more than 4.0 Bcf/d of delivery points. Potential delivery points include city-gate and storage interconnects with Nicor Gas, The Peoples Gas Light and Coke Co., Ameren, North Shore Gas Company and possible interstate pipeline interconnects with ANR Pipeline, Guardian Pipeline, Northern Border Pipeline, Horizon Pipeline, Alliance Pipeline and Natural Gas Pipeline Company of America.

Tallgrass will use the information received in this Open Season to determine the appropriate design capacity of Prairie State Pipeline and the respective receipt and delivery point interconnects. Tallgrass has begun discussions with prospective shippers concerning the terms of binding precedent agreements that, if executed, would result in those shippers becoming committed shippers on the Project. FERC approval of the Project will be sought once the appropriate design capacity of the Prairie State Pipeline is determined. As currently contemplated, Prairie State Pipeline anticipates an in-service date of Nov. 1, 2017. This date is subject to change based on the outcome of this and any subsequent open season(s) and may include a phased-in in-service.

For more information about the open season visit www.tallgrassenergylp.com/Pipelines/PrairieState.

About Tallgrass Development:

Tallgrass Development, LP, a private limited partnership organized in Delaware, owns a 50 percent interest in and operates the Rockies Express Pipeline, an approximately 1,698 mile natural gas pipeline which enables producers in the Rocky Mountain and Appalachian Basin production regions to deliver gas to the Midwest and eastern parts of the country. Tallgrass Development owns Tallgrass Terminals which is constructing crude oil terminal facilities near Sterling, Colorado and owns an interest in the Deeprock Cushing crude oil terminal. Tallgrass Development also provides crude oil transportation to customers in Wyoming and the surrounding region, including servicing the Bakken production area of North Dakota and eastern Montana, through its majority ownership interest in Tallgrass Pony Express Pipeline, LLC.

Tallgrass Development is the sponsor of, and owns a majority of the limited partnership interests in, Tallgrass Energy Partners, LP (NYSE: TEP). To learn more, please visit our website at www.tallgrassenergy.com.

About AGL Resources:

AGL Resources Inc. (NYSE: GAS) is an Atlanta-based energy services holding company with operations in natural gas distribution, retail operations, wholesale services and midstream operations. AGL Resources serves approximately 4.5 million utility customers through its regulated distribution subsidiaries in seven states, including approximately 2.2 million customers in Illinois. The company also serves approximately 630,000 retail energy customers and approximately 1.2 million customer service contracts through its SouthStar Energy Services joint venture and Pivotal Home Solutions, which market natural gas and related home services. Other non-utility businesses include asset management for natural gas wholesale customers through Sequent Energy Management and ownership and operation of natural gas storage facilities. AGL Resources is a member of the S&P 500 Index. For more information, visit www.aglresources.com.

Forward-Looking Statements

This press release includes “forward-looking statements.” All statements, other than statements of historical facts, included in this press release that address activities, events or developments that are expected, believed or anticipated will or may occur in the future are forward-looking statements. Without limiting the generality of the foregoing, forward-looking statements contained in this press release specifically include the potential design capacity of the pipeline; the route and length of the pipeline; the potential receipt points, delivery points and delivery interconnects of the pipeline; and the projected in-service date of the pipeline. Such statements are subject to a number of assumptions, risks and uncertainties, many of which are beyond the control of the Tallgrass or AGL, which may cause actual results to differ materially from those implied or expressed by the forward-looking statements. Any forward-looking statement applies only as of the date on which such statement is made. Tallgrass and AGL disclaim any obligation to revise or update any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law.