"When you look at how much of the Marcellus Shale covers Pennsylvania, 90,000 acres isn't a huge percentage but this is about where it happens and how it happens," Johnson said. "A lot depends on where those 90,000 acres get cleared because this is a major conversion."
Johnson and others pointed out that Pennsylvania's mountainous terrain is forcing gas companies to be more judicious with drilling decisions than they might be in a state such as Texas with mile after mile of flat, open terrain.
Oddly enough, even though everything about Marcellus development is big — including pad size, water use and supporting infrastructure — the ability to accommodate up to 10 vertical wells per pad actually offers a bit of solace to conservationists.
Think about this. One vertical well on a single pad can "drain" natural gas from, say, 10 to 80 acres. But a heftier pad with numerous vertical wells to accommodate far-reaching horizontal drilling technology can pull in gas from 500 to 1,000 acres.
Thus, the impact on forests, freshwater and rare species can be lessened if those pads are strategically placed instead of scattered willy-nilly without forethought.
"The lateral reach of Marcellus wells means there is more flexibility in where pads and infrastructure can be placed relative to shallow gas," the conservancy report states. "This increased flexibility in placing Marcellus infrastructure can be used to avoid or minimize impacts to natural habitats in comparison to more densely spaced shallow gas fields."
Conservancy in Midst of Second Study
Soon, the conservancy will be releasing a second report that piggybacks onto its initial release by examining the environmental impact of the four levels of underground pipelines that are constructed to eventually deliver natural gas to customers once it is harvested from the Marcellus Shale.
For instance, a gathering pipeline is built near each drilling pad to collect the freshly extracted gas. From there, it is shipped to what's called a midstream pipeline, an intermediary that connects it to the backbone of the system, a transcontinental pipeline that delivers natural gas long distances to major markets. These large cities have storage facilities that tie into a network of distribution pipelines that deliver the finished product to commercial, industrial and residential customers.
"Those distribution lines don't have too much impact on the environment," Johnson noted. "The concern is with those other three levels of pipelines."
Preliminary estimates collected by researchers at Pennsylvania State University show that new well development will require about 10,000 miles of gathering lines that measure 18 to 24 inches in diameter and require 100 feet of right-of-way. That alone would devour another 90,000 acres of land — doubling the impact of wells, roads and accompanying infrastructure by the year 2030 to 180,000 acres.
The Penn State figure doesn't include the potential footprint of midstream or transcontinental lines, Johnson said, adding that they likely won't be included in the conservancy report because those numbers are too difficult to project at this juncture.
"Clearly, the heart of some of Pennsylvania's best natural habitats lies directly in the path of future energy development," the conservancy report warned. "Integrating … conservation priorities into energy planning, operations and policy by energy companies and government agencies sooner rather than later could dramatically reduce these impacts."