The buyer of an 84-mile pipeline encircling Philadelphia has disclosed detailed plans to convert the pipeline from oil to natural gas, saying the project would require several new compressor and valve stations to move fuel to its Marcus Hook destination.

Adelphia Gateway LLC, which announced in November it is buying the underused pipeline for $189 million from Talen Energy Corp., filed its 1,285-page application Friday with the Federal Energy Regulatory Commission (FERC). Adelphia, a subsidiary of New Jersey Resources, announced the filing late Monday.

"This important project will utilize existing infrastructure to provide greater access to clean, safe, affordable natural gas to underserved markets in the Greater Philadelphia region," Stephen Westhoven, chief operating officer of New Jersey Resources, said in a statement.

The company asked FERC to approve the project by Aug. 1 so that it can complete the purchase of the pipeline, which is now known as Interstate Energy Co. LLC.

The underground pipeline now delivers either oil or natural gas to two Talen power plants in Northampton County, but would be converted to exclusively transport gas. Adelphia Gateway plans to convert the southern 50-mile portion of the pipeline, which formerly carried oil and has been idle since 2014, to transport gas southward to customers in Montgomery, Chester, and Delaware Counties.

The pipeline is the latest piece in a massive regional build-out of energy infrastructure to accommodate new demand for natural gas, triggered by the boom in fracked gas from the region's shale fields. The pipelines have aroused fierce resistance from neighbors and environmentalists, who oppose the expansion of fossil-fuel consumption.

The Adelphia conversion project would require construction of two new 5,625-horsepower compressor stations, near Quakertown and in Marcus Hook. Adelphia also wants to build a new valve station at one of two proposed locations in Concord Township, Delaware County: Off Baltimore Pike, west of Stoney Bank Road, or next to Springlawn Road, near Purple Martin Drive.

The plans include several meter and regulator facilities,  typically where the pipeline connects with customers or meets other pipelines, and eight new "blowdown" assemblies located at existing valve stations. A blowdown is the release of gas from a pipeline to the atmosphere to relieve pressure so the pipe can undergo maintenance.

Adelphia also proposes to build two new 16-inch-diameter lateral pipes to connect the planned Marcus Hook compressor station to the gas distribution systems of Peco Energy Co. and Delmarva Power.

The company said the conversion would create "minimal environmental impacts" and the need to acquire few new easements. Nevertheless, the project has already drawn flack from environmental groups.

Adelphia in November conducted an "open season" to solicit bids from potential new customers who would use the pipeline, and said it received more than twice as many bids as the pipeline's 250,000-cubic foot capacity. The robust interest prompted the Sierra Club of New Jersey to warn that Adelphia wants to double the pipeline's capacity, though the company's filing does not include any expansion plans.

The company did not disclose its primary customers, but the interconnections with Peco and Delmarva Power suggest that local utilities and their customers could tap into the new capacity. Other potential customers include the Energy Transfer Partners' Marcus Hook Industrial Complex, the Monroe Energy refinery in Trainer, and the Braskem polypropylene plant in Marcus Hook, which could use the gas for power generation or as a raw material in petrochemical production.

"The project will also increase the reliability and flexibility of the natural gas pipeline grid in the area by adding new capacity to the market and increasing the number of interconnections along the grid," the company said in the filing.

The 18-inch diameter pipeline connects with the Texas Eastern natural gas pipeline at an existing interchange near Rich Hill Road in Richland Township, Bucks County, where a new compressor station is proposed. The pipeline also intersects with two other interstate pipelines.

The pipeline was built in the 1970s to deliver oil from Sunoco's former Marcus Hook refinery to power plants owned by Pennsylvania Power & Light Co. It was partly converted to natural gas in 1996 as oil began to fall from favor as a fuel source for electricity generation.

Adelphia will continue to supply natural gas on the northern 34-mile section of the pipe to Talen Energy's Martins Creek and Lower Mount Bethel generating stations.

Adelphia's parent company, New Jersey Resources, which is based in Wall, N.J., also owns New Jersey Natural Gas.

In addition to FERC approval, the project will require review by the Pennsylvania Public Utility Commission, which regulates the current pipeline.