A local study of air emissions in the Barnett Shale suggests that trucks serving the oil and gas field spend an average of six hours per trip in extended idling, contributing to air pollution and ozone levels in North Texas.
The study, conducted by the North Central Texas Council of Governments, was part of a broader study that estimated five air pollutants from oil and gas-related vehicles over three benchmark periods: 2006, 2012 and 2018.
Emission levels for each pollutant were broken down by phase of work in the Barnett Shale — drilling, completion, production and extended idling. According to the report “Development of Oil and Gas Mobile Source Inventory in the Barnett Shale,” extended idling occurs during loading and unloading of cargo, and data show that this phase contributes to the majority of emissions.
Between 2006 and 2012, the number of completed oil and gas wells in six North Texas counties more than doubled, from about 5,900 to more than 14,700. So did the amount of idling time, from 4.7 million hours in 2006 to 10.7 million hours in 2012, according to the study.
Although the town of Little Elm enforces anti-idling provisions, Denton County is not among the four North Texas counties with idling restrictions. Those counties with restrictions are Collin, Dallas, Kaufman and Tarrant counties.
Denton County Commissioner Hugh Coleman said an idling restriction might be something for the county to consider. Coleman said he does not recall the county ever considering a restriction in the 20-plus years he has worked for the county.
“I can’t remember it ever being considered,” Coleman said. “Anything we can do to improve air quality would be a good thing to look at.”
Air emissions data from the Environmental Protection Agency was used to help determine the amount of pollutants created by each truck, according to Lori Pampell Clark, a principal transportation planner at the regional agency. She co-authored the final report with fellow staff members Shannon Stevenson and Chris Klaus.
Combined with the average distance traveled and average number of trips completed per day, Clark, Stevenson and Klaus were able to estimate how much carbon monoxide, nitrogen oxides, volatile organic compounds and other particles are being pumped into the North Texas atmosphere by oil and gas trucks.
Funded by the Texas Commission on Environmental Quality, the study acquired data via interviews and surveys from a small sample of trucking contractors that transport cargo, including produced water, to and from the Barnett Shale. The survey responses were highly consistent with one another, including those regarding the amount of time per trip spent idling, the study found.
Twelve North Texas counties were part of the air quality study, including Denton, Tarrant and other core counties of the Barnett Shale. In addition to conducting its own survey and research, the agency staff also gathered data from the Texas Railroad Commission and the Texas Department of Motor Vehicles, along with interviews and meetings with industry participants.
Clark said the agency is working on a number of potential strategies to reduce idling, from community awareness websites to more tangible solutions such as trucks with cleaner engines and more efficient truck stops.
The agency’s “Engine Off North Texas” initiative, for example, seeks to educate and inform residents and local governments as well as drivers. A map shows idle restrictions by city and county, and offers information on how and when to report idling vehicles.
With personal vehicle charging stations appearing more frequently at gas stations and parking garages, a similar technology for commercial trucks has been shown to significantly reduce both the number of hours spent idling and the amount of emissions produced.
Traditional truck stops can be upgraded with external heating and air conditioning connections, called “electrification.” Individual hookups function similar to window units, which are then connected to the trucker’s rig. Drivers who idled because of the weather or the perishable cargo they were hauling can now maintain cabin and trailer temperatures and reduce air pollution simultaneously.
With the agency’s ambitious plan to significantly reduce North Texas air pollution over the next five years, electrification could be a step in the right direction.
“We’ve devoted grant funding to all of [the truck stops] because this type of idle reduction project is particularly cost-effective,” Clark said.
Currently, five stops in Dallas, Tarrant, Johnson and Wise counties are equipped with electrification. Additional future electrified truck stop sites are expected to be announced later this year, she said.
As of December, there were 17,494 active wells in the Barnett Shale, which covers about 25 counties. Most of the wells are located in Denton, Johnson, Tarrant and Wise counties.
North Texas has not been able to meet the eight-hour standard for ozone under the Clean Air Act when it was set in 1997. State environmental officials must write and submit to federal officials a new plan to meet a far stricter standard, 75 ppb, for 10 North Texas counties, including Wise County, which was added this year.