Williams Partners Achieves Key 2017 Strategic Execution Milestone – Placing the Fifth of Transco’s 2017 ‘Big 5’ Expansions into Service

Williams Partners L.P. (NYSE: WPZ) announced today that it has successfully placed into service its Virginia Southside II expansion project, the fifth of Transco’s “Big 5” expansions to be placed into service this year. These five, fully-contracted expansion projects (Gulf Trace, Hillabee Phase 1, Dalton, New York Bay and Virginia Southside II) combine to add more than 2.8 million dekatherms per day (Dth/d) of firm transportation capacity to the Transco pipeline system this year, increasing Transco’s design capacity by nearly 25 percent.

“The Virginia Southside II project was placed into service on time and under budget and highlights our continued execution on growth projects,” said Alan Armstrong, chief executive officer of Williams Partners’ general partner. “The timely execution of these five projects within our original collective capital budget is further evidence of Williams Partners’ sector-leading capabilities to permit, contract and construct expansion projects that serve the growing needs of our customers and meet the investment requirements of our unitholders.”

The Virginia Southside II project expands the capacity of Williams Partners’ Transco pipeline system by 250,000 Dth/d to supply Dominion Virginia Power’s new electric generation facility in Greensville County, Virginia.

Williams Partners is also delivering on project execution as planned for 2018. Construction continues on schedule in Pennsylvania on the greenfield portion of the Atlantic Sunrise project. The partnership is targeting a mid-2018 in-service date for this expansion of the existing Transco natural gas pipeline which is designed to increase deliveries by 1.7 million Dth/d as it connects abundant Marcellus gas supplies with markets in the Mid-Atlantic and Southeastern U.S.

Construction also continues on Phase 2 of Williams Partners’ Garden State Expansion project. After placing Phase 1 of the project in service on Sept. 9, 2017, the partnership is targeting an in-service date of second-quarter 2018 for Phase 2, which includes a new compressor station on the Transco Trenton Woodbury Lateral in Burlington County, New Jersey. When placed into full service, this fully-contracted expansion project will deliver up to 180,000 Dth/d of additional natural gas capacity to New Jersey Natural Gas Company.

The trend of effective execution in permitting and regulatory processes on Transco projects also continues. On Nov. 21, the Federal Energy Regulatory Commission (FERC) issued a Certificate of Public Convenience and Necessity authorizing Williams Partners’ Gulf Connector Expansion project. This project is a 475,000 Dth/d expansion of the Transco pipeline system in Texas and Louisiana to connect U.S. natural gas supplies with global liquefied natural gas (LNG) markets.

Constructed in two phases, the Gulf Connector Expansion project is designed to deliver 75,000 Dth/d of natural gas to Freeport LNG Development, L.P.’s liquefaction project and 400,000 Dth/d to Cheniere Energy’s Corpus Christi liquefaction terminal with both phases expected to be placed in service in the first half of 2019.

Transco, the nation’s largest-volume and fastest-growing interstate natural gas pipeline system, is a wholly owned subsidiary of Williams Partners L.P. Transco delivers natural gas to customers through its 10,200-mile pipeline network whose mainline extends nearly 1,800 miles between South Texas and New York City. The system is a major provider of cost-effective natural gas services that reaches U.S. markets in 12 Southeast and Atlantic Seaboard states.

About Williams Partners

Williams Partners is an industry-leading, large-cap natural gas infrastructure master limited partnership with a strong growth outlook and major positions in key U.S. supply basins. Williams Partners has operations across the natural gas value chain including gathering, processing and interstate transportation of natural gas and natural gas liquids. Williams Partners owns and operates more than 33,000 miles of pipelines system wide – including the nation’s largest volume and fastest growing pipeline – providing natural gas for clean-power generation, heating and industrial use. Williams Partners’ operations touch approximately 30 percent of U.S. natural gas. Tulsa, Okla.-based Williams (NYSE: WMB), a premier provider of large-scale U.S. natural gas infrastructure, owns approximately 74 percent of Williams Partners.

Portions of this document may constitute “forward-looking statements” as defined by federal law. Although the partnership believes any such statements are based on reasonable assumptions, there is no assurance that actual outcomes will not be materially different. Additional information about issues that could lead to material changes in performance is contained in the partnership’s annual and quarterly reports filed with the Securities and Exchange Commission.