For every natural gas well in Pennsylvania targeting the Marcellus Shale, the heavy truck traffic it requires could be causing up to $23,000 in damage to state roadways, according to a study commissioned by the Rand Corp. and conducted in part by Carnegie Mellon University.
In an 11-page report, "Estimating the Consumptive Use Costs of Shale Natural Gas Extraction on Pennsylvania Roadways," researchers found that -- based upon Marcellus Shale development data from 2011 -- estimated first-order costs from heavy truck traffic on the state-maintained roads amounted to $13,000-$23,000 per well for all state roadway types. Excluding state roads with the lowest traffic volumes, the costs declined to $5,000-$10,000 per well.
The researchers formulated their damage estimates after compiling the number of heavy truck trips required to construct and operate a single well, roadway life and reconstruction costs, and truck travel and repair costs.
"The number of heavy truck trips associated with each Marcellus Shale gas well depends on whether the water used for hydraulic fracturing [fracking] arrives by truck or pipeline," the researchers said. They also took into account "whether the produced water is disposed of by truck or pipeline; how many wells are located on each well pad; the amount of equipment; materials and water needed for each site, and other factors."
Based upon 2011 data from the New York State Department of Environmental Conservation (DEC), the researchers assumed each truck traveled a distance of 20 miles each way to and from the well site. They also assumed that half of the trucks coming to wells were four-axle single-unit trucks, while the other half were six-axle single trailers. DEC data was used because the researchers assumed figures in Pennsylvania would be similar.
Under those assumptions, the researchers estimated that a single well in Pennsylvania required 625 one-way, loaded heavy truck trips during peak well pad development, and 1,148 one-way, loaded heavy truck trips during the early stages of well pad development.
According to figures from the Pennsylvania Department of Transportation (PennDOT), shale gas activity in 2011 accounted for 46% of the traffic on its Class D roads, which are classified as highways that are not in the National Highway System (NHS), but had average daily traffic (ADT) of more than 2,000 vehicles. PennDOT said lane mile reconstruction costs, in 2012 dollars, were estimated at $2.57 million.
By comparison, PennDOT said shale gas activity accounted for 28% of traffic on its Class E roads (non-NHS, ADT less than 2,000) and 22% of traffic on Class C highways (NHS). In 2012 dollars, lane mile reconstruction costs were $2.33 million and $2.68 million respectively.
The researchers said road damage could be mitigated through a fee or tax, regulations, or by adjusting the infrastructure system in a way to absorb expected damages at lower costs. They also suggested a comprehensive strategy to possibly include all three.
"In our context, plans for future pavements structures and construction quality, as well as road maintenance policies, could be adjusted to support heavier traffic volumes," the researchers said. "A recent example for this approach is in Texas' oil-rich Eagle Ford shale play, where officials have indicated their intention to upgrade some heavily used roads."
In 2010, PennDOT reported that the state was paying $30-35 million more than the gas industry for road repairs (see Shale Daily, Dec. 30, 2010).
Localities can use fees collected under Act 13, Pennsylvania's omnibus Marcellus Shale law, toward road repairs. They received $102.7 million in impact fee revenue for oil and gas drilling in 2012, according to the Pennsylvania Public Utility Commission (see Shale Daily, June 14, 2013).