Gas leak

Last updated

A gas leak refers to a leak of natural gas or another gaseous product from a pipeline or other containment into any area where the gas should not be present. Gas leaks can be hazardous to health as well as the environment. Even a small leak into a building or other confined space may gradually build up an explosive or lethal concentration of gas. [1] Natural gas leaks and the escape of refrigerant gas into the atmosphere are especially harmful, because of their global warming potential and ozone depletion potential. [2]

Contents

Leaks of gases associated with industrial operations and equipment are also generally known as fugitive emissions. Natural gas leaks from fossil fuel extraction and use are known as fugitive gas emissions. Such unintended leaks should not be confused with similar intentional types of gas release, such as:

Gas leaks should also not be confused with "gas seepage" from the earth or oceans - either natural or due to human activity.

Fire and explosion safety

Pure natural gas is colorless and odorless, and is composed primarily of methane. Unpleasant scents in the form of traces of mercaptans are usually added, to assist in identifying leaks. This odor may be perceived as rotting eggs, or a faintly unpleasant skunk smell. Persons detecting the odor must evacuate the area and abstain from using open flames or operating electrical equipment, to reduce the risk of fire and explosion.

As a result of the Pipeline Safety Improvement Act [3] of 2002 passed in the United States, federal safety standards require companies providing natural gas to conduct safety inspections for gas leaks in homes and other buildings receiving natural gas. The gas company is required to inspect gas meters and inside gas piping from the point of entry into the building to the outlet side of the gas meter for gas leaks. This may require entry into private homes by the natural gas companies to check for hazardous conditions.

Harm to vegetation

Gas leaks can damage or kill plants. [4] [5] In addition to leaks from natural gas pipes, methane and other gases migrating from landfill garbage disposal sites can also cause chlorosis and necrosis in grass, weeds, or trees. [6] In some cases, leaking gas may migrate as far as 100 feet (30 m) from the source of the leak to an affected tree. [7]

Harm to animals

Methane is an asphyxiant gas which can reduce the normal oxygen concentration in breathing air. Small animals and birds are also more sensitive to toxic gas like carbon monoxide that are sometimes present with natural gas. The expression "canary in a coal mine" derives from the historical practice of using a canary as an animal sentinel to detect dangerously high concentrations of naturally occurring coal gas. [8]

Greenhouse gas emissions

Methane, the primary constituent of natural gas, is up to 120 times as potent a greenhouse gas as carbon dioxide. Thus, the release of unburned natural gas produces much stronger effects than the carbon dioxide that would have been released if the gas had been burned as intended. [9]

Leak grades

In the United States, most state and federal agencies have adopted the Gas Piping and Technology Committee (GPTC) standards for grading natural gas leaks.

A Grade 1 leak is a leak that represents an existing or probable hazard to persons or property, and requires immediate repair or continuous action until the conditions are no longer hazardous. Examples of a Grade 1 leak are:

A Grade 2 leak is a leak that is recognized as being non-hazardous at the time of detection, but justifies scheduled repair based on probable future hazard. Examples of a Grade 2 Leak are:

A Grade 3 leak is non-hazardous at the time of detection and can be reasonably expected to remain non-hazardous. Examples of a Grade 3 Leak are:

Studies

In 2012, Boston University professor Nathan Phillips and his students drove along all 785 miles (1,263 km) of Boston roads with a gas sensor, identifying 3300 leaks. [9] The Conservation Law Foundation produced a map showing around 4000 leaks reported to the Massachusetts Department of Public Utilities. [9] In July 2014, the Environmental Defense Fund released an interactive online map based on gas sensors attached to three mapping cars which already were being driven along Boston streets to update Google Earth Street View. This survey differed from the previous studies in that an estimate of leak severity was produced, rather than just leak detection. This map should help the gas utility to prioritize leak repairs, as well as raising public awareness of the problem. [9]

In 2017, Rhode Island released an estimated 15.7 million metric tons of greenhouse gases, about a third of which comes from leaks in natural gas pipes. This figure, published in 2019, was calculated based on an assumed leakage rate of 2.7% (as that is the rate of leakage in the nearby city of Boston). The study's authors estimated that fixing the leaks would incur an annual cost of $1.6 billion to $4 billion. [10]

Regulation

Massachusetts

Legislation passed in 2014 [11] requires gas suppliers to make greater efforts to control some of the 20,000 documented leaks in the US state of Massachusetts. The new law requires grade 1 and 2 leaks to be repaired if the street above a gas pipe is dug up, and requires priority be given to leaks near schools. It provides a mechanism for increased revenue from ratepayers (up to 1.5% without further approval) to cover the cost of repairs and replacement of leak-prone materials (like cast iron and non-cathodically protected steel) on an accelerated basis. The law sets a target of 20 years for replacement of pipes made from leak-prone materials if feasible given the revenue cap; as of 2015, Columbia Gas of Massachusetts (formerly named "Bay State Gas"), Berkshire Gas, Liberty Utilities, National Grid, and Unitil say they will meet this target, but NSTAR says it will take 25 years to complete. [12] [13] Leaks, statistics on leak-prone materials, and financial statements are reported annually to the Department of Public Utilities, which also has responsibility for rate-setting.

Additional proposals not included in the law would have required grade 3 leaks to be repaired during road construction, and priority for leaks which are killing trees or which were near hospitals or churches. [14] [15]

An attorney for the Conservation Law Foundation stated that the leaks were worth $38.8 million in lost natural gas, which also contributes 4% of the state's greenhouse gas emissions. [15] A federal study prompted by US Senator Edward J. Markey concluded that Massachusetts consumers paid approximately $1.5 billion from 2000–2011 for gas which leaked and benefited no one. [14] Markey has also backed legislation that would implement similar requirements at the national level, along with financing provisions for repairs. [14] [ needs update ]

History

Catastrophic gas leaks, such as the Bhopal disaster are well-recognized as problems, but the more-subtle effects of chronic low-level leaks have been slower to gain recognition.

Other contexts

In work with dangerous gases (such as in a lab or industrial setting), a gas leak may require hazmat emergency response, especially if the leaked material is flammable, explosive, corrosive, or toxic.

See also

Related Research Articles

<span class="mw-page-title-main">Natural gas</span> Gaseous fossil fuel

Natural gas is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane (97%) in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbon dioxide, nitrogen, hydrogen sulfide, and helium are also usually present. Methane is colorless and odorless, and the second largest greenhouse gas contributor to global climate change after carbon dioxide. Because natural gas is odorless, odorizers such as mercaptan are commonly added to it for safety so that leaks can be readily detected.

Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. These fuels are used in machinery that operates in space where ordinary fuel cannot be used, due to the very low temperatures often encountered in space, and the absence of an environment that supports combustion. Cryogenic fuels most often constitute liquefied gases such as liquid hydrogen.

<span class="mw-page-title-main">Gas stove</span> Type of cooking stove

A gas stove is a stove that is fuelled by combustible gas such as natural gas, propane, butane, liquefied petroleum gas, syngas, or other flammable gas. Before the advent of gas, cooking stoves relied on solid fuels such as coal or wood. The first gas stoves were developed in the 1820s and a gas stove factory was established in England in 1836. This new cooking technology had the advantage of being easily adjustable and could be turned off when not in use. The gas stove, however, did not become a commercial success until the 1880s, by which time supplies of piped gas were available in cities and large towns in Britain. The stoves became widespread on the European Continent and in the United States in the early 20th century.

<span class="mw-page-title-main">Landfill gas</span> Gaseous fossil fuel

Landfill gas is a mix of different gases created by the action of microorganisms within a landfill as they decompose organic waste, including for example, food waste and paper waste. Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Trace amounts of other volatile organic compounds (VOCs) comprise the remainder (<1%). These trace gases include a large array of species, mainly simple hydrocarbons.

<span class="mw-page-title-main">Greenhouse gas emissions by the United States</span> Climate changing gases from the North American country

The United States produced 5.2 billion metric tons of carbon dioxide equivalent greenhouse gas (GHG) emissions in 2020, the second largest in the world after greenhouse gas emissions by China and among the countries with the highest greenhouse gas emissions per person. In 2019 China is estimated to have emitted 27% of world GHG, followed by the United States with 11%, then India with 6.6%. In total the United States has emitted a quarter of world GHG, more than any other country. Annual emissions are over 15 tons per person and, amongst the top eight emitters, is the highest country by greenhouse gas emissions per person. However, the IEA estimates that the richest decile in the US emits over 55 tonnes of CO2 per capita each year. Because coal-fired power stations are gradually shutting down, in the 2010s emissions from electricity generation fell to second place behind transportation which is now the largest single source. In 2020, 27% of the GHG emissions of the United States were from transportation, 25% from electricity, 24% from industry, 13% from commercial and residential buildings and 11% from agriculture. In 2021, the electric power sector was the second largest source of U.S. greenhouse gas emissions, accounting for 25% of the U.S. total. These greenhouse gas emissions are contributing to climate change in the United States, as well as worldwide.

<span class="mw-page-title-main">Shale gas</span> Natural gas trapped in shale formations

Shale gas is an unconventional natural gas that is found trapped within shale formations. Since the 1990s a combination of horizontal drilling and hydraulic fracturing has made large volumes of shale gas more economical to produce, and some analysts expect that shale gas will greatly expand worldwide energy supply.

<span class="mw-page-title-main">Gas-fired power plant</span> One or more generators which convert natural gas into electricity

A gas-fired power plant, sometimes referred to as gas-fired power station, natural gas power plant, or methane gas power plant, is a thermal power station that burns natural gas to generate electricity. Gas-fired power plants generate almost a quarter of world electricity and are significant sources of greenhouse gas emissions. However, they can provide seasonal, dispatchable energy generation to compensate for variable renewable energy deficits, where hydropower or interconnectors are not available. In the early 2020s batteries became competitive with gas peaker plants.

Environmental issues in Canada include impacts of climate change, air and water pollution, mining, logging, and the degradation of natural habitats. As one of the world's significant emitters of greenhouse gasses, Canada has the potential to make contributions to curbing climate change with its environmental policies and conservation efforts.

<span class="mw-page-title-main">Methane</span> Hydrocarbon compound (CH₄); main component of natural gas

Methane is a chemical compound with the chemical formula CH4. It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it poses technical challenges due to its gaseous state under normal conditions for temperature and pressure.

Fugitive emissions are leaks and other irregular releases of gases or vapors from a pressurized containment – such as appliances, storage tanks, pipelines, wells, or other pieces of equipment – mostly from industrial activities. In addition to the economic cost of lost commodities, fugitive emissions contribute to local air pollution and may cause further environmental harm. Common industrial gases include refrigerants and natural gas, while less common examples are perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride.

<span class="mw-page-title-main">Landfills in the United States</span> American landfills

Municipal solid waste (MSW) – more commonly known as trash or garbage – consists of everyday items people use and then throw away, such as product packaging, grass clippings, furniture, clothing, bottles, food scraps and papers. In 2018, Americans generated about 265.3 million tonnes of waste. In the United States, landfills are regulated by the Environmental Protection Agency (EPA) and the states' environmental agencies. Municipal solid waste landfills (MSWLF) are required to be designed to protect the environment from contaminants that may be present in the solid waste stream.

<span class="mw-page-title-main">Landfill gas utilization</span>

Landfill gas utilization is a process of gathering, processing, and treating the methane or another gas emitted from decomposing garbage to produce electricity, heat, fuels, and various chemical compounds. After fossil fuel and agriculture, landfill gas is the third largest human generated source of methane. Compared to CO2, methane is 25 times more potent as a greenhouse gas. It is important not only to control its emission but, where conditions allow, use it to generate energy, thus offsetting the contribution of two major sources of greenhouse gases towards climate change. The number of landfill gas projects, which convert the gas into power, went from 399 in 2005 to 519 in 2009 in the United States, according to the US Environmental Protection Agency. These projects are popular because they control energy costs and reduce greenhouse gas emissions. These projects collect the methane gas and treat it, so it can be used for electricity or upgraded to pipeline-grade gas. These projects power homes, buildings, and vehicles.

<span class="mw-page-title-main">Exemptions for fracking under United States federal law</span>

There are many exemptions for fracking under United States federal law: the oil and gas industries are exempt or excluded from certain sections of a number of the major federal environmental laws. These laws range from protecting clean water and air, to preventing the release of toxic substances and chemicals into the environment: the Clean Air Act, Clean Water Act, Safe Drinking Water Act, National Environmental Policy Act, Resource Conservation and Recovery Act, Emergency Planning and Community Right-to-Know Act, and the Comprehensive Environmental Response, Compensation, and Liability Act, commonly known as Superfund.

<span class="mw-page-title-main">Aliso Canyon gas leak</span> Massive natural gas leak in southern California

The Aliso Canyon gas leak was a massive methane leak in the Santa Susana Mountains near the neighborhood of Porter Ranch in the city of Los Angeles, California. Discovered on October 23, 2015, gas was escaping from a well within the Aliso Canyon underground storage facility. This second-largest gas storage facility of its kind in the United States belongs to the Southern California Gas Company, a subsidiary of Sempra Energy. On January 6, 2016, Governor Jerry Brown issued a state of emergency. On February 11, the gas company reported that it had the leak under control. On February 18, state officials announced that the leak was permanently plugged.

Increasing methane emissions are a major contributor to the rising concentration of greenhouse gases in Earth's atmosphere, and are responsible for up to one-third of near-term global heating. During 2019, about 60% of methane released globally was from human activities, while natural sources contributed about 40%. Reducing methane emissions by capturing and utilizing the gas can produce simultaneous environmental and economic benefits.

Fugitive gas emissions are emissions of gas to atmosphere or groundwater which result from oil and gas or coal mining activity. In 2016, these emissions, when converted to their equivalent impact of carbon dioxide, accounted for 5.8% of all global greenhouse gas emissions.

Diversified Energy Company plc, formerly Diversified Gas & Oil plc, is a gas and oil production company operating in the Appalachian Basin and the Central Region in the United States. It is listed on the London Stock Exchange and the New York Stock Exchange and is a constituent of the FTSE 250 Index.

<span class="mw-page-title-main">Methane leak</span>

A methane leak comes from an industrial facility or pipeline and means a significant natural gas leak: the term is used for a class of methane emissions. Satellite data enables the identification of super-emitter events that produce methane plumes. Over 1,000 methane leaks of this type were found worldwide in 2022. As with other gas leaks, a leak of methane is a safety hazard: coalbed methane in the form of fugitive gas emission has always been a danger to miners. Methane leaks also have a serious environmental impact. Natural gas can contain some ethane and other gases, but from both the safety and environmental point of view the methane content is the major factor.

References

  1. Kletz, Trevor A. (2001). Learning from Accidents. Gulf Professional Publishing. ISBN   075064883X.
  2. Stocker, Thomas (ed.). Climate change 2013 : the physical science basis : Working Group I contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. New York. ISBN   978-1-10741-532-4. OCLC   881236891.
  3. "Text of H.R. 3609 (107th): Pipeline Safety Improvement Act of 2002 (Passed Congress version)". GovTrack.us.
  4. Lindsay, Jay (March 26, 2007). "Trust Targets Gas Leaks That Kill Trees". The Washington Post. Retrieved 2013-11-28.
  5. Joyce, Christopher. "Boston's Leaky Gas Lines May Be Tough On The Trees". NPR. National Public Radio. Archived from the original on 4 March 2016. Retrieved 2013-11-28.
  6. Fraedrich, Bruce R. "Gas Injury to Trees: Identification and Treatment" (PDF). Bartlett Tree Research Laboratories. Retrieved 2013-11-28.
  7. Baniecki, John F. "Gas Leak". Tree Problems. West Virginia University Extension Service. Archived from the original on December 3, 2013. Retrieved 2013-11-28.
  8. Doherty, Peter (2013). Their Fate is Our Fate: How Birds Foretell Threats to Our Health and Our World. Melbourne University Publishing Limited. ISBN   978-1-61519-182-6.
  9. 1 2 3 4 Struck, Doug (July 16, 2014). "Google Earth captures city's leaky gas pipelines". Boston Globe. Retrieved 2014-07-18.
  10. Kuffner, Alex (12 September 2019). "R.I. greenhouse-gas emissions rise 45% in new calculation of methane leaks". Providence Journal. Retrieved 13 September 2019.
  11. "Acts of 2014, Chapter 149: AN ACT RELATIVE TO NATURAL GAS LEAKS".
  12. "Executive Office of Energy and Environmental Affairs" (PDF). Mass.gov. Retrieved 2018-09-15.
  13. "Gas System Enhancement Plan Orders".
  14. 1 2 3 Ailworth, Erin (July 7, 2014). "New Mass. law aims to speed repairs to gas leaks". Boston Globe. Archived from the original on 2014-07-12. Retrieved 2014-07-18.
  15. 1 2 Metzger, Andy (Jun 11, 2013). "With natural gas leaks widespread, lawmakers revisit fixes". Wicked Local Marblehead. Archived from the original on December 3, 2013. Retrieved 2013-11-28.