A Cleaner Path to Energy Independence
As energy demand increases more than 50 percent over the next two decades, the world will remain dependent on fossil fuels for generations to come, according to a recent Department of Energy report. Oil production in the U.S. has risen over the last four years while dependence on foreign oil has declined slightly. Domestic natural gas production has also risen. Although an increase in the demand for renewable energy is also expected, global consumption of natural gas is predicted to rise 52 percent.
The issue of energy security garnered attention in 1973 when an Arab oil embargo starved U.S. markets for six months. This event sparked a domestic focus on energy independence and catalyzed efforts to reduce America’s dependence on foreign sources of oil and other energy sources. According to the Congressional Budget Office, disruptions in the supply of energy commodities also increase domestic energy prices, burdening households and businesses.
A report from the news magazine The Week describes new drilling technology as a key driver in the move toward energy independence. Hydraulic fracturing, or fracking, is a relatively new process by which gases and liquids are used to break up underground rock formations to release the natural gas trapped inside. This process has made it possible to access huge deposits of natural gas in shale formations located throughout the United States. The largest deposits of shale gas have been found in Texas (Bennett Shale); Louisiana (Haynesville Shale); and Pennsylvania, Maryland, and New York (Marcellus Shale) – all of which add up to around a 100-year supply at current usage rates. Chesapeake Energy reports that about 99 percent of the natural gas we use is produced in North America, and natural gas is 70 percent less expensive than oil, making gas a cheaper and cleaner path to energy independence.
In light of these developments, the secure and efficient transfer of natural gas from ground to market is an important concern for the continued viability of natural gas as a domestic source of energy.
History and advantages
Discovery of massive natural gas fields in Texas, Kansas, and Oklahoma coupled with advances in pipeline technology changed the face of the gas industry early in the twentieth century. Welding technologies developed in the 1920s made it possible to build longer pipelines and transport natural gas to distant markets. By the 1950s, a national market existed for natural gas. Oil shortages in the 1960s followed by the 1973 OPEC oil crisis spurred research seeking ways to expand production of natural gas. This research led to the advances in horizontal drilling that are driving today’s increased recovery of shale gas.
Natural gas offers advantages as a bridge fuel to be used as more sustainable alternatives are developed. According to engineer and author RP Siegel, it emits 45 percent less carbon dioxide than coal and 30 percent less carbon dioxide than oil. It also is a low emitter of sulfur oxides and nitrogen oxides, which, along with carbon dioxide, are classified as criteria pollutants—air pollutants that cause smog, acid rain, and other health hazards. Natural gas also meets national security concerns stemming from dependency on foreign oil.
The expansion of domestic natural gas production has several advantages. Natural gas is well-known and versatile as a fuel for home heating and cooking, and there is an established and relatively safe delivery infrastructure. Further, according to data compiled by Chesapeake Energy, combustion of natural gas provides 22 percent of the nation’s energy yet only 16 percent of its greenhouse gas emissions. Despite these positive aspects, several inherent challenges to expanding the production and utilization of natural gas as a reliable energy source still exist.
Appeal for caution
Critics have concerns about possible environmental risks associated with natural gas production. They not only cite issues related to horizontal drilling but also question if reduced U.S. carbon dioxide emissions from energy generation credited to a shift from coal to natural gas can be sustained with increased production. Increased production of natural gas naturally leads to increased transmission and transportation which heightens the environmental concerns of natural gas as an energy source.
Although natural gas emits the least pollutants of any fossil fuel when it is burned to produce energy, it is 80-95 percent methane in its natural state. Despite being cleaner to burn, methane is a potent greenhouse gas that can inflict significant environmental damage if leaked during recovery or transmission. Some researchers hypothesize that any gains in improved emissions brought about through increased production of natural gas could be offset by increased leakage of methane into the air. A study from the Proceedings of the National Academy of Science found that if the leakage rises to six percent, then a natural gas plant would contribute more to global warming than a coal plant would over the first 25 years of their life spans.
Reducing pipeline leakage during transfer and transmission, therefore, is a major concern for both industry and the environment.
Next-generation pipeline assessment
Pipelines stretch more than 2.6 million miles across the United States. Eighty-one percent of the pipelines are for gas distribution and 12 percent for gas transmission and gathering. Pipeline leakage in this extensive network threatens the environment, industry production, and ultimately the viability of natural gas as a leading domestic source of energy. However, the U.S. Department of Transportation reports that pipelines are the safest method for transporting natural gas, which makes it a more secure source of domestic energy.
Reducing leakage by maintaining pipeline integrity represents a huge investment for oil and gas companies. Current inspection methods involve examining a pipeline internally with a device known as a smart pig (pipeline inspection gauge) and then conducting an exterior inspection of areas where damage—cracks or dents—has been indicated. The exterior inspection usually involves digging up the line and removing the exterior coating for a visual examination of the steel. These labor-intensive inspection practices are costly, putting the cost of pipeline maintenance into billions of dollars a year for large companies and raising additional obstacles to the efficient production of this important energy source.
And these protocols do not evaluate the best predictor of material failure—residual stress.
Recent advancements in the maintenance of natural gas pipelines will improve the safe and efficient transfer of gas from ground to market. When they founded Generation 2 Materials Technology (G2MT) three years ago, Centenary alumna Angelique Lasseigne ’02 and co-founder Joshua Jackson saw possibilities for improving leak prevention by developing a more accurate way to evaluate damage. Having both completed a Ph.D. at the Colorado School of Mines, Lasseigne and Jackson are metallurgical engineers who recognized an opportunity to improve safety and reduce failures by offering a method to determine the real integrity of materials.
“Many years of metallurgical research have shown that stress, not geometry, is the most important influence on the potential for failure of a damaged area,” explained Lasseigne. “A re-rounded dent might hold more residual stress than a deep gouge but not even be identified for visual inspection using current inspection protocols.”
The Department of Transportation funded a G2MT project that led to the development of a hand-held tool that can assess residual stress in damaged regions of pipelines through an exterior examination that does not require removal of pipe coatings. Lasseigne and Jackson are now working with the Department of Transportation and partners in the oil and gas industry to test the equipment and gather outcome data.
“The new system will improve pipeline integrity management by coupling quantitative data with advanced modeling techniques to provide an accurate characterization of the stress around a damaged area,” promises Jackson. “Our goal is to have a commercial product ready for the market in one to two years.”
Improved safety through better prioritization of needed repairs is not the only advantage of this new method for materials assessment. The new system reduces costs by being less invasive and more accurate than current methods.
A wider vision
Because materials play a critical role in virtually every major industry, the technologies being used to improve pipeline integrity management have applications beyond oil and gas. G2MT also serves the power generation, aerospace, chemical processing, and nuclear industries.
Lasseigne is confident as she confronts complex problems across these varying fields in part because of her Centenary experience.
“My professors never told us, ‘This is hard.’ Their approach was, ‘This is easy. Let’s understand it and figure it out.’” This same ethic is reflected in the G2MT company vision to use material technology and knowledge to improve the world.
The Big Picture
Increased oil, natural gas, and renewable energy production and energy efficiency improvements will reduce U.S. reliance on imported energy sources, according to the 2012 Annual Energy Outlook produced by the U.S. Energy Information Administration. The agency’s administrator Howard Gruenspecht added, “These projections reflect increased energy efficiency throughout the economy, updated assessments of energy technologies and domestic energy resources, the influence of evolving consumer preferences, and projected slow economic growth.”
Scientific innovation like the work of G2MT contributes to more environmentally sensitive processes of production and transportation of natural gas domestically, helping to decrease U.S. dependence on foreign energy imports, while advancing the global shift toward more sustainable energy sources.