Gas venting

Last updated
A diagram showing the geologic sources of alkane hydrocarbon gases which accompany the extraction of coal and crude oil, or which are themselves the target of extraction. (Non) Conventional Deposits.svg
A diagram showing the geologic sources of alkane hydrocarbon gases which accompany the extraction of coal and crude oil, or which are themselves the target of extraction.

Gas venting, more specifically known as natural-gas venting or methane venting, is the intentional and controlled release of gases containing alkane hydrocarbons - predominately methane - into Earth's atmosphere. It is a widely used method for disposal of unwanted gases which are produced during the extraction of coal and crude oil. Such gases may lack value when they are not recyclable into the production process, have no export route to consumer markets, or are surplus to near-term demand. In cases where the gases have value to the producer, substantial amounts may also be vented from the equipment used for gas collection, transport, and distribution.

Contents

Gas venting contributes strongly to climate change. [1] [2] Nevertheless, many individual cases are sufficiently small and dispersed to be deemed "safe" with regard to immediate health hazards. Large and concentrated releases are usually abated with gas flares to produce relatively less-harmful carbon dioxide gas. Gas venting and flaring that are performed as routine practices are especially wasteful and may be eliminated in many modern industrial operations, where other low-cost options are available to utilize the gas. [3]

Gas venting is not to be confused with similar types of gas release, such as those from:

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

Oil field practice relating to unwanted gas

Petroleum extraction and storage with flaring of the associated gas at a rural site. Orvis State oil well and gas tanks and natural gas flare - Evanson Place - Arnegard North Dakota - 2013-07-04 (9287569795).jpg
Petroleum extraction and storage with flaring of the associated gas at a rural site.
Incomplete gas flaring that also creates excessive black carbon. Gas flare, PetroChina Jabung field, Jambi, Indonesia.jpg
Incomplete gas flaring that also creates excessive black carbon.

Petroleum extraction from oil wells, where acquiring crude oil is the primary and sometimes sole financial objective, is generally accompanied by the extraction of substantial amounts of so-called associated petroleum gas (i.e. a form of raw natural gas). Global statistics from year 2012 show that the majority (58%) of this gas was re-injected for storage and to help maintain well pressure, 27% was sent to consumption markets, and the remaining 15% was vented or flared near the well site. [4]

100 million tons of the vented associated gas was combusted in flares worldwide, equal to about 3-4% of all gas produced from oil and gas wells. [4] The flared gas yielded nearly 350 million tons of CO2-equivalent emissions of greenhouse gases, contributing about 1% of the 33 billion tons of carbon dioxide (CO2) released from the burning of all fossil fuels. [5] Flare Gas Recovery Systems (FGRS) are being increasingly implemented as a more economically productive alternative to flaring. [6] : 50–52 

Preferably, all of the unwanted gas would at least be abated in gas flares, but this has not been achieved in practice. For example, the vented volumes from individual wells are sometimes too small and intermittent, and may present other difficulties (e.g. high concentrations of contaminants) that make flaring more technically and economically challenging. Also, gas will continue to effervesce from the crude oil for some time after it is moved into storage tanks at the well site and transported elsewhere. This gas may also be routed to a flare stack, utilized, or designed to escape without mitigation through vents or pressure regulators. [7]

Global tracking estimates from the International Energy Agency (IEA) during year 2019 indicate that an additional 32 million tons of methane were vented without abatement from all petroleum extraction; including onshore conventional oil, offshore oil, unconventional oil, and downstream oil activities. When including the amount released from incomplete gas flares and fugitive emissions, the estimated total is about 37 million tons. [8]

Matthew Johnson, from the Energy and Emissions Research Lab (EER) at Carleton University in Ottawa, Ontario, Canada, said in a December 2023 interview that—contrary to common beliefs—venting, particularly from heavy oil facilities designed for normal operations, is the primary source of methane emissions in the oil and gas industry. Johnson stresses the urgency of swiftly retrofitting oil and gas sites, considering that the associated costs are reasonable, based on various studies. The estimated cost for retrofitting for the total industry in Canada is estimated at $3.3 billion between 2027 and 2040 for implementing both venting and flaring requirements in the . [9] Jonson said that while fossil fuels are not going to be phased out "overnight", "when it comes to methane emissions, we have a solution and we can implement it right now." [10] A 2023 Energy and Emissions Research Lab report discusses challenges in meeting the 2030 methane reduction targets under the Global Methane Pledge, due to uncertainties in emission levels from oil and gas operations. The research, which centers on Alberta, Canada —the Canadian province with the largest oil and gas-industry—presents a methane inventory for 2021 that exceeds the official federal inventory by 1.5 times. The study underscores that nearly two-thirds of emissions—primarily stemming from uncontrolled tanks, pneumatics, and unlit flares, result from gas venting—indicating substantial opportunities for mitigation. Notably, methane intensities in Alberta are four times higher than those in neighboring British Columbia, highlighting the necessity for independent monitoring and reporting ensuring the success of emission reduction initiatives. [11] Gas venting in the oil and gas industry has gained attention in Alberta, Canada, particularly in light of proposed legislative changes aimed at reducing methane emissions. Federal Environment Minister Steven Guilbeault presented a plan during the 2023 United Nations Climate Change Conference in Dubai, outlining a national cap-and-trade system to curb emissions without hindering production. The proposed framework aims to cap 2030 emissions at 35 to 38 percent below 2019 levels, aligning with the federal government's objective of achieving net-zero carbon emissions in the sector by 2050. Given that the oil and gas industry contributes to 28 percent of Canada's emissions, these proposed changes signal a significant effort to address environmental concerns and combat climate change. [9]

Coal mining and coalbed methane activity

A large fan supplying fresh air to a mine ventilation shaft. Methane and coal dust are removed by exhaust air. LARGE FAN EQUIPMENT USED TO BLOW FRESH AIR INTO VIRGINIA-POCAHONTAS COAL COMPANY MINE ^2 NEAR RICHLANDS, VIRGINIA IT... - NARA - 556402.jpg
A large fan supplying fresh air to a mine ventilation shaft. Methane and coal dust are removed by exhaust air.
A ventilation air methane thermal oxidizer. VAMTOX.jpg
A ventilation air methane thermal oxidizer.

Substantial amounts of methane-rich gas are trapped and adsorbed within coal formations, and are unavoidably desorbed in association with coal mining. In some cases of sub-surface mining, a formation is permeated with boreholes prior to and/or during extraction work, and the so-called firedamp gases allowed to vent as a safety measure. Also during work, methane enters the ventilation air system at concentrations as high as 1%, and is usually freely exhausted from the mine opening. Such ventilation air methane (VAM) is the largest source of methane from all operating and decommissioned coal mines worldwide. Substantial methane also continues to desorb from coal placed into storage and from abandoned mines. [12]

The U.S. Environmental Protection Agency projects that by year 2020, global methane releases from coal mines throughout the world will exceed 35 million tons or 800 million tons of CO2-equivalent emissions, and account for 9% of all global methane emissions. China contributes over 50% of the total, followed by the United States (10%) and Russia (7%), and then by Australia, Ukraine, Kazakhstan, and India (3-4% each). About 200 mines across a broad scope of countries had implemented technology by the year 2015 to capture about 3 million tons of methane, either for economic use or for abatement in gas flares or thermal oxidizers. [12]

Outcroppings, seams, or formations near the surface are also sometimes permeated with wells to extract and capture the methane, in which event it is classified as a form of unconventional gas. [13] Such coalbed methane capture can reduce the volume of gas seepage that would otherwise occur naturally, while in-turn adding emissions of carbon dioxide once the fuel is utilized elsewhere. [14] [15]

Global tracking estimates from the IEA during 2019 suggest that about 40 million tons of methane were released from all activities related to coal mining. This total amount includes all vented, fugitive and seepage emissions. [7] [16]

Gas field and gas pipeline practices

A gas pipeline compressor station. Gas is vented by design from the seals of some gas compressor equipment. Winslow Compressor Station, February 2019.jpg
A gas pipeline compressor station. Gas is vented by design from the seals of some gas compressor equipment.

In gas fields, acquiring non-associated petroleum gas (i.e. another form of raw natural gas) is the primary financial objective, and very little is unwanted compared to the gas produced in oil fields or coal mines. The majority of venting emissions instead occur during the pipeline transport to trading & distribution hubs, refineries, and consumer markets. [6] : 6–8 

The U.S. Department of Energy reports that a majority of the venting within U.S. gas industry operations in year 2017 occurred at compressor stations and from pneumatically operated controllers and regulators. [6] : 7  Improved maintenance strategies and advanced equipment technologies either exist or are being developed to reduce such venting. [17]

Global tracking estimates from the IEA during year 2019 further indicate that about 23 million tons of methane were vented from all gas industry segments, including onshore conventional gas, offshore gas, unconventional gas, and downstream gas activities. When including the amount released from fugitive emissions, the estimated total is about 43 million tons. [8]

Historical context

Associated petroleum and coal mining gases were sometimes considered troublesome, dangerous, low value: a "free" by-product associated with financially more lucrative coal or liquid hydrocarbon recovery that had to be dealt with. The growth of international gas markets, infrastructure and supply chains have done much to change this. It is also becoming more of a standard practice to:

Today, it is financially viable to develop even relatively small hydrocarbon reservoirs containing non-associated gas (i.e. with little or no oil) close to a market or export route, as well as large, remote accumulations.

Fossil gas was recently promoted by some industry advocates and policy makers as a "bridge fuel" that could yield the least waste, and thus environmental damage and accompanying economic losses, during the transition from finite fossil-fuel reserves to more sustainable sources. [18] However, the actual volumes of methane released cumulatively over the supply chain have a near-term climate warming impact which already rivals, and may grow to exceed, that from using coal and oil. [19]

Environmental impact

Radiative forcing of different contributors to climate change in 2011, as reported in the fifth IPCC assessment report. Physical Drivers of climate change.svg
Radiative forcing of different contributors to climate change in 2011, as reported in the fifth IPCC assessment report.

Venting and other releases of gaseous hydrocarbons have increased steadily throughout the industrial age alongside the rapid growth in production and consumption of fossil fuels. [20] The International Energy Agency estimates that total annual methane emissions from the oil and gas industry alone rose from about 63 to 82 million tons over years 2000 thru 2019; an average increase of about 1.4% per year. [7] [21] Globally, the IEA estimates that the geologic extraction of coal, crude oil, and natural gas is responsible for 20% of all methane emissions. [16] Other researchers have found evidence that their contribution may be substantially higher; 30% or greater. [22] [23]

Methane's atmospheric concentration has nearly doubled over the last century, and is already a factor 2.5 greater than at any point in the last 800,000 years. [24] Methane is a potent warming gas despite its lower abundance compared to atmospheric carbon dioxide. Atmospheric methane is responsible for at least one-quarter and as much as one-third of the changes in radiative forcing that drive near-term climate warming. [2] [25] [26]

The ethane, propane, and butane components of natural gas have much shorter atmospheric lifetimes (ranging from about 1 week to 2 months) compared to methane (1-2 decades) and carbon dioxide (1-2 centuries). They consequently do not become well-mixed into the atmosphere and have much lower atmospheric abundances. [27] Nevertheless, their oxidation ultimately leads to the creation of longer-lived carbon compounds that also disturb the atmosphere and the planetary carbon cycle through a variety of complex pathways. [28]

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 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.

<span class="mw-page-title-main">Fossil fuel</span> Fuel formed over millions of years from dead plants and animals

A fossil fuel is a hydrocarbon-containing material such as coal, oil, and natural gas, formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. Fossil fuels may be burned to provide heat for use directly, to power engines, or to generate electricity. Some fossil fuels are refined into derivatives such as kerosene, gasoline and propane before burning. The origin of fossil fuels is the anaerobic decomposition of buried dead organisms, containing organic molecules created by photosynthesis. The conversion from these materials to high-carbon fossil fuels typically require a geological process of millions of years.

<span class="mw-page-title-main">Coalbed methane</span> Form of natural gas extracted from coal beds

Coalbed methane, coalbed gas, or coal seam gas (CSG) is a form of natural gas extracted from coal beds. In recent decades it has become an important source of energy in United States, Canada, Australia, and other countries.

<span class="mw-page-title-main">Fossil fuel power station</span> Facility that burns fossil fuels to produce electricity

A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat.

<span class="mw-page-title-main">Gas flare</span> Safety device for burning off flammable gas

A gas flare, alternatively known as a flare stack, flare boom, ground flare, or flare pit, is a gas combustion device used in places such as petroleum refineries, chemical plants and natural gas processing plants, oil or gas extraction sites having oil wells, gas wells, offshore oil and gas rigs and landfills.

<span class="mw-page-title-main">Greenhouse gas emissions</span> Sources and amounts of greenhouse gases emitted to the atmosphere from human activities

Greenhouse gas (GHG) emissions from human activities intensify the greenhouse effect. This contributes to climate change. Carbon dioxide, from burning fossil fuels such as coal, oil, and natural gas, is one of the most important factors in causing climate change. The largest emitters are China followed by the United States. The United States has higher emissions per capita. The main producers fueling the emissions globally are large oil and gas companies. Emissions from human activities have increased atmospheric carbon dioxide by about 50% over pre-industrial levels. The growing levels of emissions have varied, but have been consistent among all greenhouse gases. Emissions in the 2010s averaged 56 billion tons a year, higher than any decade before. Total cumulative emissions from 1870 to 2017 were 425±20 GtC from fossil fuels and industry, and 180±60 GtC from land use change. Land-use change, such as deforestation, caused about 31% of cumulative emissions over 1870–2017, coal 32%, oil 25%, and gas 10%.

<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.

This article is intended to give an overview of the greenhouse gas emissions in the U.S. state of Kentucky.

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">Environmental impact of the energy industry</span>

The environmental impact of the energy industry is significant, as energy and natural resource consumption are closely related. Producing, transporting, or consuming energy all have an environmental impact. Energy has been harnessed by human beings for millennia. Initially it was with the use of fire for light, heat, cooking and for safety, and its use can be traced back at least 1.9 million years. In recent years there has been a trend towards the increased commercialization of various renewable energy sources. Scientific consensus on some of the main human activities that contribute to global warming are considered to be increasing concentrations of greenhouse gases, causing a warming effect, global changes to land surface, such as deforestation, for a warming effect, increasing concentrations of aerosols, mainly for a cooling effect.

<span class="mw-page-title-main">Environmental impact of the petroleum industry</span>

The environmental impact of the petroleum industry is extensive and expansive due to petroleum having many uses. Crude oil and natural gas are primary energy and raw material sources that enable numerous aspects of modern daily life and the world economy. Their supply has grown quickly over the last 150 years to meet the demands of the rapidly increasing human population, creativity, knowledge, and consumerism.

<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.

Associated petroleum gas (APG), or associated gas, is a form of natural gas which is found with deposits of petroleum, either dissolved in the oil or as a free "gas cap" above the oil in the reservoir. The gas can be utilized in a number of ways after processing: sold and included in the natural-gas distribution networks, used for on-site electricity generation with engines or turbines, reinjected for secondary recovery and used in enhanced oil recovery, converted from gas to liquids producing synthetic fuels, or used as feedstock for the petrochemical industry, but much of it worldwide is flared.

<span class="mw-page-title-main">Coalbed methane in the United States</span>

The 2017 production of coalbed methane in the United States was 0.98 trillion cubic feet (TCF), 3.6 percent of all US dry gas production that year. The 2017 production was down from the peak of 1.97 TCF in 2008. Most coalbed methane production came from the Rocky Mountain states of Colorado, Wyoming, and New Mexico.

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.

Methane reservoirs on Earth are mainly found in

<span class="mw-page-title-main">Greenhouse gas emissions by China</span> Emissions of gases harmful to the climate from China

China's greenhouse gas emissions are the largest of any country in the world both in production and consumption terms, and stem mainly from coal burning, including coal-fired power stations, coal mining, and blast furnaces producing iron and steel. When measuring production-based emissions, China emitted over 14 gigatonnes (Gt) CO2eq of greenhouse gases in 2019, 27% of the world total. When measuring in consumption-based terms, which adds emissions associated with imported goods and extracts those associated with exported goods, China accounts for 13 gigatonnes (Gt) or 25% of global emissions.

The Oil and Gas Climate Initiative (OGCI), is an international industry-led organization which includes 12 member companies from the oil and gas industry: BP, Chevron, CNPC, Eni, Equinor, ExxonMobil, Occidental, Petrobras, Repsol, Saudi Aramco, Shell and TotalEnergies represent over "30% of global operated oil and gas production." It was established in 2014 and has a mandate to work together to "accelerate the reduction of greenhouse gas emissions" in full support of the Paris Agreement and its aims."

<span class="mw-page-title-main">Greenhouse gas emissions by Russia</span> Greenhouse gas emissions originating from Russia and efforts to reduce them

Greenhouse gas emissionsbyRussia are mostly from fossil gas, oil and coal. Russia emits 2 or 3 billion tonnes CO2eq of greenhouse gases each year; about 4% of world emissions. Annual carbon dioxide emissions alone are about 12 tons per person, more than double the world average. Cutting greenhouse gas emissions, and therefore air pollution in Russia, would have health benefits greater than the cost. The country is the world's biggest methane emitter, and 4 billion dollars worth of methane was estimated to leak in 2019/20.

<span class="mw-page-title-main">Routine flaring</span> Disposal of unwanted gas during extraction

Routine flaring, also known as production flaring, is a method and current practice of disposing of large unwanted amounts of associated petroleum gas (APG) during crude oil extraction. The gas is first separated from the liquids and solids downstream of the wellhead, then released into a flare stack and combusted into Earth's atmosphere. Where performed, the unwanted gas has been deemed unprofitable, and may be referred to as stranded gas, flare gas, or simply as "waste gas". Routine flaring is not to be confused with safety flaring, maintenance flaring, or other flaring practices characterized by shorter durations or smaller volumes of gas disposal.

References

  1. ↑ 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.
  2. 1 2 "Europe Outlines Bold New Climate Vision, While Underscoring Value of Methane Emission Reductions". Environmental Defense Fund. Retrieved 2020-04-13.
  3. ↑ "Global Gas Flaring Reduction Partnership". World Bank. Retrieved 2020-04-13.
  4. 1 2 "Zero Routine Flaring by 2030 Q&A". World Bank. Retrieved 2020-04-10.
  5. ↑ "Global Energy & CO2 Status Report 2019: The latest trends in energy and emissions in 2018". International Energy Agency (Paris). 2019-03-01. Retrieved 2020-04-10.
  6. 1 2 3 "Natural Gas Flaring and Venting: State and Federal Regulatory Overview, Trends, and Impacts" (PDF). U.S. Department of Energy. 2019-06-01. Retrieved 2020-04-09.
  7. 1 2 3 "Fuels and Technologies - Methane abatement". International Energy Agency (Paris). 2019-11-01. Retrieved 2020-09-08.
  8. 1 2 "Methane Tracker - Country and regional estimates". International Energy Agency (Paris). 2019-11-01. Retrieved 2020-04-10.
  9. 1 2 Cram, Stephanie (14 December 2023). "Oil and gas flaring became a political flash point in Alberta last week. We take a look at why". CBC News. Retrieved 14 December 2023.
  10. ↑ Tremblay, Alyssa. "Methane Census to Help Define a Path to Meet 2030 Reduction Targets". Carleton Newsroom. Retrieved 14 December 2023.
  11. ↑ Conrad, Bradley M.; Tyner, David R.; Li, Hugh Z.; Xie, Donglai; Johnson, Matthew R. (15 November 2023). A Measurement-Based Upstream Oil and Gas Methane Inventory for Alberta, Canada Reveals Higher Emissions and Different Sources than Official Estimates. Communications Earth & Environment (Report). doi: 10.1038/s43247-023-01081-0 . Retrieved 14 December 2023.
  12. 1 2 "Coalbed Methane Outreach Program - Frequent Questions About Coal Mine Methane". U.S. Environmental Protection Agency. Retrieved 2020-04-09.
  13. ↑ "Coalbed Methane Extraction Industry". U.S. Environmental Protection Agency. Retrieved 2020-04-10.
  14. ↑ Mullane, Shannon (July 9, 2019). "Outdoors industry taps into Southern Ute methane capture project". Durango Herald. Retrieved 2020-04-10.
  15. ↑ "Southern Ute Indian Tribe: Natural Methane Capture and Use". Native Energy. 2018. Retrieved 2020-04-10.
  16. 1 2 "Methane Tracker - Analysis". International Energy Agency (Paris). 2019-11-01. Retrieved 2020-04-10.
  17. ↑ "EPA's Voluntary Methane Programs for the Oil and Natural Gas Industry". U.S. Environmental Protection Agency. Retrieved 2020-04-09.
  18. ↑ Joel Kirkland (June 25, 2010). "Natural gas could serve as a "bridge" fuel to low carbon future". Scientific American. Retrieved 2020-04-10.
  19. ↑ Howarth, R.W. (2014). "A bridge to nowhere: methane emissions and the greenhouse gas footprint of natural gas" (PDF). Energy Science & Engineering. Society of Chemical Industry and John Wiley & Sons Ltd. 2 (2): 47–60. doi: 10.1002/ese3.35 .
  20. ↑ Heede, R. (2014). "Tracing anthropogenic carbon dioxide and methane emissions to fossil fuel and cement producers, 1854–2010". Climatic Change. 122 (1–2): 229–241. Bibcode:2014ClCh..122..229H. doi: 10.1007/s10584-013-0986-y .
  21. ↑ "Methane Tracker 2020 - Methane from oil and gas". International Energy Agency (Paris). 2019-11-01. Retrieved 2020-04-13.
  22. ↑ "Fossil fuel industry's methane emissions far higher than thought". The Guardian. 2016-10-05. Retrieved 2020-04-14.
  23. ↑ "Methane emitted by humans vastly underestimated, researchers find". phys.org. 2020-02-19. Retrieved 2020-04-14.
  24. ↑ Hannah Ritchie; Max Roser (2020). "CO₂ and Greenhouse Gas Emissions: CH4 Concentrations". Our World in Data. Published online at OurWorldInData.org. Retrieved 2020-04-14.
  25. ↑ "Global Methane Emissions and Mitigation Opportunities" (PDF). Global Methane Initiative. 2020.
  26. ↑ "IPCC Fifth Assessment Report - Radiative Forcings (AR5 Figure SPM.5)". The Intergovernmental Panel on Climate Change. 2013.
  27. ↑ Hodnebrog, ∅.; Dalsøren, S.; Myhre, G. (2018), "Lifetimes, direct and indirect radiative forcing, and global warming potentials of ethane (C2H6), propane (C3H8), and butane (C4H10)", Atmos. Sci. Lett., 2018, 19:e804 (2): e804, Bibcode:2018AtScL..19E.804H, doi: 10.1002/asl.804
  28. ↑ Rosado-Reyes, C.; Francisco, J. (2007), "Atmospheric oxidation pathways of propane and its by‐products: Acetone, acetaldehyde, and propionaldehyde", Journal of Geophysical Research, 112 (D14310): 1–46, Bibcode:2007JGRD..11214310R, doi: 10.1029/2006JD007566
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.