Williams Partners LP has started up its New York Bay Expansion, adding 115,000 Dth/d on its Transcontinental Gas Pipe Line (Transco) system to serve the New York City (NYC) market, the Tulsa-based master limited partnership said Monday.

Entering service just in time for the winter heating season, the New York Bay Expansion is designed to provide incremental firm transportation capacity to utility National Grid, which serves 1.8 million customers in the NYC boroughs of Brooklyn, Queens and Staten Island, and on Long Island, NY.

“As we have seen with the recent storms that have devastated other states and neighboring regions, the security of energy supply needs to be protected and enhanced,” said Ken Daly, president of National Grid New York. “A secure and resilient supply of natural gas is critical to the local NYC and Long Island communities we serve. Williams’ New York Bay Expansion project will help ensure safe, reliable and secure energy to meet our needs.”

The expansion, which received FERC approval last summer, consists of additional horsepower at three existing compressor stations, along with modifications to existing metering and regulating stations in New Jersey, Pennsylvania and New York.

“Our Transco pipeline has a long history of providing NYC with safe, reliable natural gas service,” Williams COO Michael Dunn said. This expansion “continues that long-standing commitment, providing additional supplies of affordable natural gas to support the region’s economic vitality and ensure a reliable energy supply to the new NYC area.”

The New York Bay Expansion is the fourth of five Transco expansions scheduled to enter service in 2017. The Gulf Trace, Hillabee Phase 1 and Dalton Expansion projects all entered service earlier this year, combining with New York Bay to add a total 2.5 million Dth/d of incremental capacity on Transco this year. Williams said it plans to place its Virginia Southside II project in service during the fourth quarter.

Also this year, Transco began partial service on its Atlantic Sunrise expansion, designed to allow additional volumes of Northeast Pennsylvania production to reach downstream markets via Transco. Williams was cleared to begin construction on the 183-mile greenfield portion of Atlantic Sunrise last month.

Transco is a 10,000-mile pipeline system that runs almost 1,800 miles along the Atlantic seaboard from South Texas to NYC. The system delivers about half of the natural gas consumed by NYC, according to Williams.

The New York Bay Expansion should offer some help for a demand region that has dealt with pipeline constraints. Transco Zone 6 NY, like points further north in New England, is prone to significant price swings compared to gas traded in other regions. Over the past 30 days, gas traded at Transco Zone 6 NY has traded as low as $1.21/MMBtu on Sept. 28 and has high as $3.17/MMBtu on Sept. 19. That compares to a trading range of $2.83/MMBtu to $3.14/MMBtu at Henry Hub over the same timeframe, according to Daily GPI.