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

• Williams Partners placed Virginia Southside II project into service
  on Dec. 1
• Virginia Southside II joins Gulf Trace, Hillabee Phase 1, Dalton
  and New York Bay in being placed into service this year
• The “Big 5” increases Transco’s design capacity by nearly 25 percent
• FERC approves Gulf Connector Expansion project

TULSA, Okla.–(BUSINESS WIRE)–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.

Contacts

Williams Partners L.P.
Media Contact:
Christopher
Stockton, 713-215-2010
or
Investor Contact:
Brett
Krieg, 918-573-4614