Williams Partners L.P. (NYSE: WPZ) today announced that its Transco pipeline system received binding commitments from nine shippers for 100 percent of the 1.7 million dekatherms of firm transportation capacity under its proposed Atlantic Sunrise expansion project. The project includes 15-year shipper commitments from producers, local distribution companies and power generators.

The project represents vital energy infrastructure that would connect surging, new supplies of natural gas in the Marcellus producing region in northeastern Pennsylvania with growing demand centers along the Atlantic Seaboard.

Williams Partners expects to bring Atlantic Sunrise into service in the second half of 2017, assuming all necessary regulatory approvals are received in a timely manner.

Transco is the nation's largest-volume interstate natural gas pipeline system. It 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 reach U.S. markets in 12 Southeast and Atlantic Seaboard states, including major metropolitan areas in New York, New Jersey and Pennsylvania.

The Atlantic Sunrise project adds to the list of vital Transco mainline expansions, including Leidy Southeast and Virginia Southside. Transco is pursuing expansions that between 2013 and year-end 2017 are expected to add more than 50 percent to its system capacity.

"We expect to invest some $5 billion over the 2013 to 2017 timeframe in Transco expansions that represent vital connections between diverse, surging supplies of domestic natural gas and growing demand centers on the Eastern Seaboard from New York City to the far Southeast," said Alan Armstrong, president and chief executive officer of Williams Partners. "We see this significant investment as an early read on Transco's continuing growth opportunities. We look forward to working with shippers to develop this vital energy infrastructure.

"Already in this heating season, Transco has set peak-day throughput records on three separate occasions. The demand for our pipeline capacity on those peak days was above and beyond the peaks that we could attribute to weather, even the brutal polar-vortex episodes all of our markets have endured," Armstrong said.

The Atlantic Sunrise project will consist of compression and looping of the Transco Leidy line in Pennsylvania along with a greenfield pipeline segment, referred to as the Central Penn Line, connecting the northeastern Marcellus producing region to the Transco mainline near Station 195 in southeastern Pennsylvania. The greenfield segment will be jointly owned by Transco and a third party.

Williams Partners expects its net investment in the Atlantic Sunrise project to be approximately $2.1 billion. The preliminary schedule for project permitting activity begins with Transco's planned submission in March of its request to commence the pre-filing process with the Federal Energy Regulatory Commission. The project is subject to approval by Williams Partners' Board of Directors.

About Williams Partners L.P. (NYSE: WPZ)

Williams Partners L.P. is a leading diversified master limited partnership focused on natural gas transportation; gathering, treating, and processing; storage; natural gas liquid (NGL) fractionation; and oil transportation. The partnership owns interests in three major interstate natural gas pipelines that, combined, deliver 14 percent of the natural gas consumed in the United States. The partnership's gathering and processing assets include large-scale operations in the U.S. Rocky Mountains and both onshore and offshore along the Gulf of Mexico. Williams (NYSE: WMB) owns approximately 64 percent of Williams Partners, including the general-partner interest. More information is available at www.williamslp.com, where the partnership routinely posts important information.

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. Any such statements are made in reliance on the "safe harbor" protections provided under the Private Securities Reform Act of 1995. Additional information about issues that could lead to material changes in performance is contained in the partnership's annual reports filed with the Securities and Exchange Commission.

Williams Partners L.P.
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