Air Quality: Problems and Solutions


Like any industrial activity, gas drilling and associated processes can affect air quality. Two of the major air quality concerns are:

  • Methane emissions
  • Air pollution from diesel fuel and gasoline

Methane emissions

Methane is the basic hydrocarbon in natural gas. It is also a potent greenhouse gas that traps 28 times as much heat as carbon dioxide does.

Over the years, the natural gas industry has worked hard to reduce methane leaks for several reasons.

  • Leaking methane is a safety risk, so the gas industry has focused on leak reduction for public and employee safety.
  • The need to reduce emissions related to climate change is another critical reason to keep methane out of the atmosphere.
  • In addition, gas producers are financially motivated to prevent methane leaks. That's because methane is, in essence, natural gas – so methane not captured means lost revenue.

Industry critics have claimed that more methane is emitted from shale gas production than from other types of wells. Some state that methane emissions are so high that they offset any greenhouse gas reductions created by switching from coal to natural gas for generating electricity.

In 2013, the U.S. Environmental Protection Agency estimated far lower methane emissions than previous estimates. The 2013 figure also was much lower than those put forth by the Cornell study which first cast attention on the methane issue. However, estimates still vary widely.

To bring more clarity to this issue, the Environmental Defense Fund (EDF) is leading a broad-based research effort. Working with more than 90 universities, research facilities and gas companies, EDF wants to learn more precisely how much methane is emitted from gas production to end use, and where those emissions are coming from.

NW Natural is participating in one of the 16 studies, with a focus on emissions from natural gas distribution companies. Researchers from Washington State University spent a week with NW Natural testing various points on the company’s system for methane leaks. We expect to hear results in spring of 2014.

A report published in the Proceedings of the National Academy of Sciences says a system-wide emission rate of less than 2.7 percent means that using natural gas instead of coal for electric generation has substantial greenhouse gas reduction benefits. The American Gas Association currently estimates emissions to be at 1.3 percent.

The EPA says that between 2008 and 2012, during the rapid growth of shale development, methane emissions from the natural gas system fell 14.3 percent. It appears that improvements in the natural gas distribution system, as well as at the wellhead, will continue to reduce methane emissions from natural gas production and transportation.

Diesel fuel and gasoline

Gas drilling requires a lot of motorized equipment: from generators to trucks to employee vehicles. An area with a lot of drilling may see hundreds of trucks a day, carrying water for fracking, taking water away to be disposed of and carrying other equipment and products to the site.

Traditionally, this equipment has run on diesel or gasoline. Increasingly, responsible companies are turning toward natural gas to operate their equipment and run their vehicles – reducing their carbon emissions substantially, as well as reducing nitrogen oxides, a common air pollutant from diesel and gasoline.

Natural gas is becoming a practical option for vehicle fuels, and some fleets are starting to buy vehicles that run on liquefied or compressed natural gas. Electric vehicles are another alternative.

Recently, a Texas drilling operation began using bi-fuel pumps, operating on liquefied natural gas as well as diesel, to run hydraulic fracturing operations. The new pumps reduced diesel use by 65 percent.

In addition to switching fuels, gas drillers are operating more efficiently, so they need less equipment. For example, by recycling most of the water they use on site, drillers reduce the number of trucks bringing water and removing liquid wastes.

  • Footnotes—NW Natural has not performed its own scientific or economic research on the impacts of fracking or gas production practices. The information in this section is derived from publicly available reports, studies and periodicals.