The following 3 articles from SNL discuss the problem of methane emissions from natural gas systems

Read the Manhattan Methane Emissions Study, commissioned by Damascus Citizens

Methane studies renew debate about fuel’s future in society

A rapidly mounting stack of research exploring the impact of methane emissions on natural gas’ role as a bridge fuel is dividing stakeholders on just how long that bridge should last and what can be expected on the other side.

Scientists, consultants, industry and environmental groups have poured millions into exploring the concerns about methane leakage, hoping to understand the scale of emissions and find economic means to reduce the amount of gas that escapes. The literature has found reasons for both optimism and pessimism.

While overall methane emissions may be much greater than the U.S. EPA assumes, cutting the emissions that stem from the oil and gas sector could be relatively affordable. According to one estimate from ICF International published on March 3, the hydrocarbon industry could cut methane emissions by 40% of expected 2018 levels for less than 1 cent per Mcf of produced natural gas.

ICF, which completed the work for the Environmental Defense Fund, projected that methane emissions from oil and gas production will increase from a 2011 baseline by roughly 4.5% by 2018. That projection factors in emissions reductions from expected regulatory and voluntary actions in the next few years, including air rules for the sector that were updated in April 2012.

Existing technologies and techniques could offset that increase at a low net cost because the companies implementing the emissions reduction measures would save money by retaining more of their natural gas. By volume, the largest opportunities to trim emissions are leak detection and repair at facilities and gas compressors, reducing venting of associated gas, and replacing high-emitting pneumatic devices, the study concluded.

Many companies already employ methane-emission-reducing technologies, but Mark Brownstein, associate vice president and chief counsel of the EDF’s energy and climate program, noted during a Feb. 28 conference call that policies at the state or federal level could help level the playing field industry wide. Even though ICF’s research indicated the costs to companies would be minimal, some operators concerned about the upfront investment or redirecting funds from expansion projects ought to be pushed to take steps that would benefit the climate and economy, Brownstein contended.

“Swift and decisive action by policymakers to get the policy right … is going to be critically important,” Brownstein said. “Each day that goes by … hampers our ability to deal with a warming climate and frankly denies communities air quality [improvements] they need.”

Continue reading

Aging urban gas systems require greater vigilance

Integrity management is a perpetual challenge for natural gas utilities, especially those tending to some of the nation’s oldest pipeline infrastructure in some of the most prominent cities.

While a line’s age alone is not a conclusive indicator of the pipe’s safety, older systems are more likely to include segments made of bare steel and cast iron — materials found to be susceptible to corrosion or cracking. Utilities and other pipeline operators across the country have been replacing these segments with more modern materials, but the U.S. is still home to almost 30,750 miles of cast and wrought iron mains and nearly 56,100 miles of bare steel main, according to the U.S. Pipeline and Hazardous Materials Safety Administration.

Included among those miles is the 127-year-old Consolidated Edison Co. of New York Inc. cast iron line that supplied gas to two now-collapsed buildings in New York City. The structures were leveled March 12 in a deadly explosion that the National Transportation Safety Board has said likely stemmed from a gas leak, potentially on that cast iron pipeline. However, the incident is still under investigation.

All told, the Consolidated Edison Inc. subsidiary has 1,286 miles of cast iron piping and 1,169 miles of unprotected steel lines among its 4,300 miles of gas mains, but the utility expects to replace an average of 65 miles of gas main each year for the next three years, at a cost of about $110 million annually.

The risks of the aging infrastructure are compounded by the dense population atop the pipelines, and Con Edison inspects its entire system for leaks at least once annually using mobile gas detection vehicles, the company noted recently.

Leak detection is of paramount importance in high-consequence areas such as New York City, according to Robert Ackley, head of Gas Safety Inc. Further, urban electric, telephone, cable and other lines are often underground, Ackley said, giving natural gas more subterranean conduits to get into buildings and increasing the risk a leak poses. While the high risk often motivates utilities to tackle leaks that would otherwise be considered relatively benign, urban infrastructure complicates pinpointing a leak’s source, he said. Unlike in rural or suburban areas where a utility can often probe through grass or other unpaved areas, a company operating in a city must bore holes into asphalt or concrete to find an exact leak location.

Continue reading

Group says methane emissions from gas systems underestimated

A regional environmental group said two reports on methane emissions from New York City support its claims that natural gas causes as much climate change impact as oil and coal.

“The methane leakage in the system serving NYC through [Consolidated Edison] is likely already at a level where the methane leaked has as much, or more, climate impact as the remaining approximately 95% of the gas that is actually usefully burned by consumers in NYC,” said Bryce Payne, one of the authors of the reports and an associate research professor in the environment and engineering department at Wilkes University in Wilkes-Barre, Pa.

Damascus Citizens for Sustainability, or DCS, commissioned the reports from Gas Safety Inc. A preliminary report found elevated emissions of methane in Manhattan, which the report observed is served by the local distribution system of Consolidated Edison Co. of New York Inc. An extended version of the report reviewed estimates of methane emissions by industry, government and other sources, including a method used by the U.S. EPA and the Gas Research Institute.

“Based on [its] reviews DCS is forced to conclude that those [other] estimates are so inaccurate as to be almost useless — in fact, misleading,” DCS said in an April 1 statement.

DCS has fought natural gas transportation projects in the region and warned of radon in natural gas transported from the Marcellus. Other groups and experts have examined methane emissions from gas systems.

DCS said measurements in its report showed that gas production losses and estimated gas transmission losses produce a total gas loss above 5%. “This number is well above the critical benchmark level of less than 3.2%, at which level natural gas no longer retains an advantage over other forms of fossil fuels with regard to climate change,” DCS said. “Since natural gas is 93% methane, and methane is more than 20 times more potent a greenhouse gas … than CO2, the level of leakage shows that natural gas should not be considered a ‘bridge fuel.’ We now have valuable evidence that current steps of continuing and increasing natural gas use would only accelerate climate change.”

Continue reading