Natural gas, air and water


Texas and national lawmakers continue to address issues related to energy, water and air pollution, with particular attention to natural gas and hydraulic fracturing. However, energy bills are not the priority in either the Texas or the national legislature: Both are preoccupied by budgetary and other issues.

Hydraulic fracturing for natural gas remains a contentious issue because of potential impacts to air, land and water systems. Briefly, hydraulic fracturing is a technique whereby natural gas producers inject large volumes of water with some chemical additives underground to access difficult-to-reach natural gas. Most wells are hydraulically fractured, and the practice is decades old, but recent practice has involved much larger fluid volumes in more populated areas than has historically been true. Water and land systems can be contaminated when wells are poorly constructed or when fluids leak or are improperly disposed at the surface.

During the past two weeks, a lot of attention has also been focused on natural gas (methane) emissions that occur when large volume hydraulic fracturing jobs are completed. A Cornell study by Robert Howarth, Renee Santoro and Anthony Ingraffea claims that shale gas might actually be more greenhouse gas intensive than coal because of methane leaks. (Shale gas accounts for about 15 percent of the United States’ natural gas supply right now, but this is expected to increase to about 45 percent by 2035.) Natural gas has lower carbon emissions than coal when it is burned, but methane (the main component of natural gas) is a more potent greenhouse gas than carbon dioxide, so if enough natural gas leaks, the carbon advantage can disappear. Somewhat controversially, the Cornell study assumes an unusually high value for methane’s greenhouse effect by considering a 20 year (rather than the conventional 100 year) atmospheric lifetime and using a multiplier from a recent study that challenges the international literature review. The international assessment used by the United Nations suggests methane is 25 times as potent as carbon dioxide over 100 years (72 times over 20 years), while the Cornell study assumes methane is 105 times as potent as carbon dioxide over 20 years. My calculations suggest that the Cornell study underestimates emissions from coal (coal mines emit methane too), and others have pointed out that some leakage rate assumptions are unreasonably high. However, the issue of leaking natural gas is real, should be looked at and should be mitigated where possible. Texas’ Senate Bill 104 proposes tighter regulation of natural gas releases from wells, which would partially address this problem.

On the natural gas and water front, U.S. Senators Waxman, Markey and De Gette released a report over the weekend on natural gas fracturing chemicals that calls for chemical disclosure. I wrote two weeks ago in support of Texas’ fracture fluid disclosure bills, HB 3328 and SB 1049, which would require more public information about what fluids are being used for natural gas extraction and would aid in specific analysis of potential environmental harms. While I currently believe that using natural gas is environmentally preferable to using coal for electricity in many applications, having more specific and complete information about chemicals used for hydraulic fracturing would help support that sentiment. The Waxman, Markey and De Gette report states that many of the chemicals used in hydraulic fracturing are unknown to the drilling companies, as chemical suppliers retain proprietary information. Protecting trade secrets is important: there is little incentive to innovate without some protection. However, total secrecy is inappropriate. Chemical manufacturers claim that disclosure could remove their incentive to produce greener fracturing fluids, but there is little incentive to use green fluids when you don’t know why you should stop using brown — or shall we say, black box — fluids.

The senators’ report shows that the most harmful chemicals assessed are used more in Texas than in any other state. The report gleefully and repeatedly mentions that some producers use instant coffee for hydraulic fracturing — but it also more seriously points out that Texas uses about 6 times as much 2-Butoxyethanol as the next largest user (Oklahoma), about 2.6 times as many carcinogenic chemicals as the next largest user (Colorado) and about 8 times as many chemicals regulated under the Safe Drinking Water Act as the next largest user (New Mexico). Wyoming and Arkansas already have fracturing fluid disclosure laws. Texas lawmakers recognize the importance of Texas laws and practices in this area, and a good Texas fluid disclosure law with appropriate proprietary protections could be important to natural gas development throughout the United States.