Sept 9 (Reuters) - The Transcontinental Gas Pipe Line

(Transco) applied on Friday to the Federal Energy Regulatory

Commission (FERC) for a temporary emergency certificate to

continue operating its new $1 billion natural gas project

running through five mid-Atlantic states after the regulator's

approval was vacated.

In July, a U.S. appeals court said the FERC should have

better assessed the risk of significant greenhouse gas

emissions,

throwing out

its "arbitrary and capricious" approval of the Regional

Energy Access Expansion Project.

The temporary certificate is necessary to keep Transco,

a unit of Williams Cos ( WMB ), running its facilities until the

FERC issues an order on remand from the July 30 decision by the

court.

The project is already partially in service. The FERC

approved the first phase on an interim basis in October 2023. In

June, Williams sought permission to put more of the project

already under construction into service by July 1.

A temporary certificate of public convenience and necessity

is needed in order to prevent an emergency caused by the sudden

loss of over 2,000,000 dekatherms per day of natural gas

pipeline transportation capacity in the Mid-Atlantic and

northeastern U.S., the company said.

Williams designed Regional Energy Access to help meet

rising gas demand and ease supply constraints affecting

customers in Pennsylvania, New Jersey and Maryland. The company

said the project, one of the biggest under construction in the

U.S. Northeast, will provide enough gas to serve 4.4 million

homes annually.