New techniques are needed to distinguish between leakage of methane (CH4) into surface waters from gas wells and natural sources. Here, scientists worked with >50 citizen scientists in a hydrocarbon‐rich basin (Pennsylvania, U.S.A.) to measure methane concentrations ([CH4]) in streams. These measurements were combined with published observations to form a reconnaissance dataset. The dataset was then used to categorize sites as background or as impacted by other sources of gas. For 479 samples at 131 sites, 470 were supersaturated with respect to the atmosphere (>0.08 µg/L). Sites with the lowest concentrations generally were located in low‐productivity, sandstone‐underlain upland streams, while other streams contained CH4 from sources in addition to atmospheric. The median of 63 sites not located near wetland habitats and not affected by known thermogenic influxes yielded an estimate of background [CH4] in the streams, 0.5 µg/L. The highest individual measurements (∼70 µg/L) in the stream dataset were observed in one site near a wetland and one site near a putatively leaking gas well. Inspection of the dataset revealed that values of [CH4] above a threshold for non‐wetland sites, 4 μg/L, signals gas is likely deriving from sources such as leaking gas wells, shallow organic‐rich shales, coal, or landfills. Using historical and local volunteer knowledge, we discovered 12 non‐wetland sites above the threshold that are potentially contaminated by such sources. Although sources of CH4 cannot be proven from such surveys of [CH4], stream sampling with nonscientists nonetheless allows discovery of sites of potential contamination that can be further investigated.

As natural gas has grown in importance as a global energy source, leakage of methane (CH4) from wells has sometimes been noted. Leakage of this greenhouse gas is important because it affects groundwater quality and, when emitted to the atmosphere, climate. We hypothesized that streams might be most contaminated by CH4 in the northern Appalachian Basin in regions with the longest history of hydrocarbon extraction activities. To test this, we searched for CH4contaminated streams Basin. Methane concentrations ([CH4]) for 529 stream sites are reported, in New York, West Virginia and mostly Pennsylvania. Despite targeting contaminated areas, the median [CH4], 1.1 µg/L, was lower than a recently identified threshold indicating potential contamination, 4.0 µg/L. [CH4] values were higher in a few streams because they receive high-[CH4] groundwaters, often from upwelling seeps. By analogy to the more commonly observed type of groundwater seep known as abandoned mine drainage (AMD), we introduce the term, "gas leak discharge" (GLD) for these waters where they are not associated with coal mines. GLD and AMD, observed in all parts of the study area, are both CH4-rich. Surprisingly, the region of oldest and most productive oil / gas development did not show the highest median for stream [CH4]. Instead, the median was statistically highest where dense coal mining was accompanied by conventional and unconventional oil and gas development, emphasizing the importance of CH4 contamination from coal mines into streams.

As natural gas has grown in importance as a global energy source, leakage of methane (CH4) from wells has sometimes been noted. Leakage of this greenhouse gas is important because it affects groundwater quality and, when emitted to the atmosphere, climate. We hypothesized that streams might be most contaminated by CH4 in the northern Appalachian Basin in regions with the longest history of hydrocarbon extraction activities. To test this, we searched for CH4-contaminated streams Basin. Methane concentrations ([CH4]) for 529 stream sites are reported, in New York, West Virginia and mostly Pennsylvania. Despite targeting contaminated areas, the median [CH4], 1.1 µg/L, was lower than a recently identified threshold indicating potential contamination, 4.0 µg/L. [CH4] values were higher in a few streams because they receive high-[CH4] groundwaters, often from upwelling seeps. By analogy to the more commonly observed type of groundwater seep known as abandoned mine drainage (AMD), we introduce the term, “gas leak discharge” (GLD) for these waters where they are not associated with coal mines. GLD and AMD, observed in all parts of the study area, are both CH4-rich. Surprisingly, the region of oldest and most productive oil / gas development did not show the highest median for stream [CH4]. Instead, the median was statistically highest where dense coal mining was accompanied by conventional and unconventional oil and gas development, emphasizing the importance of CH4 contamination from coal mines into streams.

No abstract

The identification of economically efficient levels of energy consumption has been identified as a goal in the process of formulating building energy performance standards. Efficient levels of fuel consumption for building space conditioning and lighting can be determined if the total costs to society of both fuels and the resources that may be substituted for fuels in building space conditioning systems are known. To test the feasibility of providing estimates of the social costs of fuels for use in developing building energy performance standards, information regarding the social costs of natural gas is surveyed and evaluated. This report identifies components of social cost, estimates values for these components, aggregates them in a national estimate and derives values for states. These estimates could then be used in minimizing the life cycle costs of building space conditioning. Estimation of the social cost of a fuel requires knowledge of producticn, processing and delivery costs, values of direct and indirect subsidies, administrative costs of regulation, and costs to society of environmental and health damages. Estimation of the marginal social cost of natural gas is quite difficult because the price distortions caused by taxes, subsidies and regulation totally obscure the true marginal cost. The accuracy of the estimates is also influenced by regional variations in source of supply, costs and technology, time periods over which estimates are made and the size of the marginal increments in supply analyzed. In addition, information gaps regarding environmental and health damages make these effects difficult to quantify. Social costs also vary depending on the form of the fuel; for example, LNG, has higher processing costs and potential damage costs. Even if all of these difficulties in deriving social cost estimates can be overcome, the fact that gas from various sources is combined in the distribution system makes it difficult to determine the appropriate allocation of costs at disparate delivery points. Costs of marginal production and transmission, regulation, direct subsidization and accidental damage to life and limb are estimated for natural gas. These estimates are summed to derive a national marginal social cost estimate; this value is then weighted using recent trends in the relative levels of state and national average costs to derive marginal cost estimates for states. iii Based on the analysis described in this report, we conclude that it is feasible to derive state-level estimates of the marginal market costs of gas from existing information. Estimates that include external costs, however, are subject to a high degree of uncertainty and should be regarded as understatements of true social costs.