TRENTON, N.J. — More than a dozen natural gas pipelines spanning hundreds of miles and carrying fuel from across the region could crisscross New Jersey if the projects — at various stages in the regulatory process — go forward.

Monday marks the end of the public comment period on the proposed 118-mile PennEast pipeline that would carry natural gas from northeastern Pennsylvania through Hunterdon and Mercer counties in New Jersey before terminating near Trenton. It’s the last step before a final environmental impact study is produced.

The deadline comes after the Marcellus Shale natural gas boom gave rise to pipeline projects in Pennsylvania, New York, New Jersey and other states. It also comes amid a broader debate between environmental groups who oppose the new pipelines in favor of wind and solar fuel sources and energy companies who bankroll the projects and see fossil fuels as an essential part of the economy.

A closer look at the issue:


THE PIPELINE PIPELINE

Pennsylvania’s energy boon stemming from the Marcellus Shale rock formation over the past decade has begun to spill over to New Jersey, which has no natural gas deposits of its own.

But the prospective pipelines resulting from that gas discovery have taken years to advance, as energy companies work through a maze of regulatory requirements. The PennEast pipeline was first proposed in 2014, and its owners — an alliance of six energy companies — hope to break ground early next year.

Charles Mason, a petroleum and natural gas economics professor at the University of Wyoming, said the permitting process for a larger pipeline similar to PennEast takes about 7 months on average.

“The very fact they’re willing to go through hoops is a good indication (that) they think there will be a nice market moving forward,” he said.

The process is viewed differently by opponents, including residents along the pipelines’ path and the company and labor groups behind the project.


ECONOMY AND ENVIRONMENT

Susan Shapiro, who lives in Lambertville near where the pipeline would cross, worries the project will harm pristine waterways in the region.

“These are the streams that my bicycling path takes me along as I crisscross my way through the region,” she said in a comment to the Federal Energy Regulatory Commission, which is reviewing the pipeline’s application. “Bordering these streams are roads, farms, and enormous old-growth trees that would be forever scarred by the imposition of the pipeline project.”

David Spigelmyer, president of the Marcellus Shale Coalition, and James Kunz, business manager for International Union of Operating Engineers Local 66, back the project and say natural gas is clean-burning and therefore not harmful to the environment.

“With natural gas, we no longer are forced to choose between growing our economy or improving our environment. Thankfully, we can have both,” they wrote in a recent Pittsburgh Post-Gazette op-ed.


THE POLITICAL CONNECTION

The Republican Christie administration included the expansion of natural gas pipelines as part of its Energy Master Plan, according to a December 2015 document from the Board of Public Utilities and the Department of Environmental Protection. Gov. Chris Christie’s administration will end in January 2018, and after two terms Democrats are hopeful they can recapture the governor’s office.

New Jersey Sierra Club director Jeff Tittel, who opposes the pipeline expansion, said a Democratic governor would be more open to appointing commissioners willing to block natural gas growth. The Delaware River Basin Commission, on which the governor has a seat, would have a vote on certain permitting for the PennEast project, for example. “The way to kill the pipeline is to slow it down,” he said.