Methane (CH4) (about 85% of natural gas) is 105 times worse than CO2 as a greenhouse gas (GHG) on a 20 year time frame and taking aerosol impacts into account. Methane leaks (3.3% in the US based on the latest US EPA data and as high as 7.9% for methane from “fracking” coal seams; a 2.6 % leakage of CH4 yields the same greenhouse effect as burning the remaining 97.4% CH4). Using this information one can determine that gas burning for electricity can be much dirtier than coal burning greenhouse gas-wise (GHG-wise). While gas burning for power generates twice as much electrical energy per tonne of CO2 produced (MWh/tonne CO2) than coal burning and the health-adverse pollution from gas burning is lower than for coal burning, gas leakage in the system actually means that gas burning for power can actually be worse GHG-wise than coal burning depending on the degree of systemic gas leakage. Gas is dirty energy and a coal-to-gas transition simply means long-term investment in another carbon fuel and delaying urgently required cessation of carbon fuel burning.
Systemic natural gas leakage in the US is about 5.4% from well to consumer.
150 SCIENTISTS. 150 scientists co-sign letter opposing new Canadian gas exploitation via Quebec LNG project (2019): “According to an industry-commissioned life cycle assessment of this gas, from its extraction to the exit point of the liquefaction plant, it would produce more than 7.8 million tonnes of greenhouse gas (GHG) per year. This means that the total emissions associated with this project within Canada would be comparable to the sum total of GHG emission reductions in Quebec since 1990. A key uncertainty in these calculations is the amount of fugitive gas emissions (leaks) occurring during its extraction, throughout the whole transport chain and after wells are abandoned. Considering that natural gas is mainly methane, a greenhouse gas 84 times more potent than CO2 over a 20-year period, the global warming effect of these leaks is enormous, and there is therefore potential for total GHG emissions associated with this project to be considerably higher than the best available estimate. Moreover, GNL Quebec carefully avoids highlighting the large amounts of downstream CO2 emissions resulting from the combustion of the gas. According to our calculations, these emissions would add roughly 30 million tonnes of CO2 per year, assuming no fugitive gas emissions. That number spikes dramatically when applying average fugitive emissions under normal operating conditions. Moreover, GNL Quebec would have no control over the end use of this gas, and there is no evidence that its use would replace coal or oil fuel. It is just as likely that this gas could replace renewable energy sources, which would only increase the world’s continued reliance on fossil fuels, and slow the desperately needed development of alternative energy technologies. Let us remember that in order to limit global warming to 1.5 C, we must reduce GHG emissions by about 45 per cent by 2030, as compared to 2010, and achieve carbon neutrality by 2050. To achieve this, it is essential that we wind down the number of fossil fuel infrastructures, not build more of them” (“Over 150 scientists urge Trudeau and Legault to reject Quebec LNG project”, National Observer, 3 June 2019: https://www.nationalobserver.com/2019/06/03/opinion/over-150-scientists-urge-trudeau-and-legault-reject-quebec-lng-project ). [Editor: if leakage were a mere 2.6% then GHG pollution from the leaked gas would equal that from the combustion of the remaining 97.4% of the gas i.e. 0.974 x 30 million tonnes CO2-equivalent = 29.2 Mt CO2-e and thus total annual GHG pollution would be 29.2 Mt CO2-e + 29.2 Mt CO2-e + 7.8 = 66.2 Mt CO2-e per year or 0.1% of global annual GHG pollution of 63.8 Gt CO-e per year with land use considered (Robert Goodland and Jeff Anfang. “Livestock and climate change. What if the key actors in climate change are … cows, pigs and chickens?”, World Watch, November/December 2009: https://pdfs.semanticscholar.org/6704/c7a0777c82357704d82b9ae8007c1197cb07.pdf?_ga=2.187734888.1597394103.1556059730-1006954717.1556059730 )].
AUSTRALIAN GOVERNMENT. Australian Government Department of Environment and Energy ( 2018): “Table 2.1: Australian energy consumption, by fuel type [2016-2017]… coal (1,936.9PJ, 31.5% total, -1.0% growth pa), oil (2,315.4 PJ, 37.7% total, +2.1% pa), gas (1,515.0 PJ, 24.7% total, +1.1% pa), renewables (378.7PJ, 6.2% total, +5.3% pa), Total (6,145.8 PJ, 100.0% total, +1.1% pa)… Table 4.1: Australian energy exports, by fuel type [2016-2017]… coal (10,685.8 PJ, 75.6% total, -2.9% pa), Gas (LNG) (2,864.5 PJ, 20.3% total, +41.4% pa), Total (14,140.1 PJ, 100.0% total, +3.7% pa) (“Australian energy update 2018”, Australian Government Department of Environment and Energy, August 2018: https://www.energy.gov.au/sites/default/files/australian_energy_update_2018.pdf ).
Australian Government Department of Environment and Energy ( 2019): “Table 2.2: Australian energy consumption, by fuel type [2017-2018]… coal (1,847.2 PJ, 29.9% total, -4.3%pa% pa% growth pa), oil (2,387.8.PJ, 38.7% total, +3.2% pa), gas (1,554.6 PJ, 25.2% total, +3.8% pa), renewables (382.1PJ, 6.2% total, +0.9% pa), Total (6,171.7 PJ, 100.0% total, +0.9% pa)… Table 4.1: Australian energy exports, by fuel type [2017-2018]… coal (10,706.6 PJ, 73.0% total, +0.7% pa), Gas (LNG) (3,376.4 PJ, 22.9% total, +18.3% pa), Total (14,739.0 PJ, 100.0% total, +4.3% pa) (“Australian energy update 2018”, Australian Government Department of Environment and Energy, August 2018: https://www.energy.gov.au/sites/default/files/australian_energy_statistics_2019_energy_update_report_september.pdf ).
[Editor: According to Australian Mining (2018): to “Australian liquefied natural gas (LNG) exports have surged by 18.5 per cent to 59.7 million tonnes (Mt) in the 2017–18 financial year, a year-over-year (YoY) gain of 9.3Mt” (Ewen Hosie, “Australian LNG exports surge to nearly 60 Mt in 2017-2018”, Australian Mining, 17 July 2018: https://www.australianmining.com.au/news/australian-lng-exports-surge-nearly-60mt-2017-18/ i.e. the 2017-2918 LNG exports of 3376.4 PJ corresponded to 59.7 Mt LNG. Assuming that all the LNG was methane (CH4) (or equivalent hydrocarbons) , the LNG combustion involves CH4 + O2 – CO2 + H2O i.e. 16 Mt CH4 yields 44 Mt CO2 (the molecular weights of CH4 and CO2 are 16 and 44, respectively). Accordingly complete combustion of the 59.7 Mt exported LNG would yield 59.7 Mt CH4 x 44 Mt CO2/12 Mt CH4 = 218.9 Mt CO2. However if we assume a 2.6% systemic leakage of gas in the overall process then total Exported LNG-based GHG pollution would be 2 x 0.974 x 218.9 Mt CO2-equivalent = 426.4 Mt CO2-e.
However we must also consider Domestic gas use of 1,554.6 PJ that corresponds to 1,554.6 PJ x 59.5 Mt gas/ 3, 376.4 PJ = 27.4 Mt CH4. complete combustion of this 27.4 Mt gas would yield 27.4 Mt CH4 x 44 Mt CO2/12 Mt CH4 = 100.5 Mt CO2. However if we assume a 2.6% systemic leakage of gas in the overall process then total Exported LNG-based GHG pollution would be 2 x 0.974 x 100.5 Mt CO2-equivalent = .195.8 Mt CO2-e.
The total GHG pollution associated with Australia’s Domestic and Exported gas (2017-2018) is thus 195.8 Mt CO2-e + 426.4 Mt CO2-e = 622.2 Mt CO2-e. One notes that the Australian Government has assessed Australia’s annual Domestic GHG pollution as steadily deceasing g in th eoeriod 2005-2013 and then steadily increasing since the Coalition was elected to government in 2013 and was 558 Mt CO2 (2018) (Lisa Cox, “Australia’s carbon emissions highest on record, data shows”, Guardian, 13 December 2018: https://www.theguardian.com/australia-news/2018/dec/13/australias-carbon-emissions-highest-on-record-data-shows ; Penny Timms and Michael Slezak, “Australia’s greenhouse gas emissions rise again, according to delayed Federal Government data”, ABC News, 6 June 2019: https://www.abc.net.au/news/2019-06-06/australian-emissions-rise-again-delayed-government-data-shows/11184906 ; Michael Slezak, “Australia’s greenhouse gas emissions soar in latest figures”, Guardian, 4 August 2017: https://www.theguardian.com/australia-news/2017/aug/04/australias-greenhouse-gas-emissions-soar-in-latest-figures ; Australian Government, Department of the Environment and Energy, “Quarterly update of Australia’s national greenhouse gas inventory: March 2019”, March 2019: https://www.environment.gov.au/system/files/resources/6686d48f-3f9c-448d-a1b7-7e410fe4f376/files/nggi-quarterly-update-mar-2019.pdf ).
Australian systemic gas leakage (fugitive emissions) is 2.8%.
Australian quarterly fugitive emissions - coal : 7.1 (March 2009) .-> 6.6 (March 2019); oil and gas: 3.6 (March 2009) -> 3.8 (March 2013) -> 8.9 (March 2019)
Annual fugitive emissions: 4 x (6.6 + 8.9) Mt CO2-e = 15.4 x 4 Mt CO2-e = 62 Mt CO2-e x Mt CH4/25 Mt CO2-e = 2.48 Mt CH4 fugitive emissions (the Australian Department of the Environmentent and Energy now assumes a Global Warming Potential or GWP of CH4 on a 100 year time frame to be 25 i.e. the GWP of 1 t CH4 is 25 times greater than that of 1 t of CO2).
Total annual fugitive emissions = 27.4Mt CH4 (Domestic) + 59,7 Mt CH4 (Exported) = 87.1 Mt CH4.
Australian systemic gas leakage (fugitive emissions) = 2.48 Mt CH4 x 100/ 87.1 My CH4 = 2.8% ].
ENVIRONMENTAL DEFENSE FUND. Environmental Defense Fund: “Although natural gas burns cleaner than either coal or oil, methane leakage throughout the natural gas supply chain — including production, processing, distribution, and vehicle end-use — reduces and sometimes eliminates the potential climate benefits of switching. Methane, the main constituent in natural gas, is a greenhouse pollutant many times more potent than carbon dioxide. In fact, pound for pound, methane is 72 times more potent as a heat-trapping pollutant than carbon dioxide in the first 20 years. U.S. Environmental Protection Agency (EPA) estimates current leak rates across the natural gas supply chain to be 2-3%... On a 20-year horizon, a methane molecule has 72 times more heat trapping capacity than a carbon |dioxide molecule. Over 100 years, that capacity shrinks to 25 times more capacity… U.S. EPA data was used as the basis for baseline leakage rates from the U.S. natural gas supply (2% from well to city gate and 0.3% in the local distribution system)… Howarth et al4 argue that leak rates for shale gas from well to city gate are 3.6-7.9% and 1.7-6.0% for conventional gas, but as with industry assertions, there are few actual measurements. The model allows for a total leak rate as high as 12% — but this is considered extremely unlikely to be the actual case… 4 Howarth, Robert W., Renee Santoro, Anthony Ingraffea. “Methane and the greenhouse-gas footprint of natural gas from shale formations,” Climatic Change, DOI 10.1007/s10584-011-0061-5, (2011). http://www.sustainablefuture.cornell.edu/news/attachments/Howarth-EtAl-2011.pdf ” (Environmental Defense Fund, “What Influence Will Switching to Natural Gas Have on Climate? User Guide for Natural Gas leakage rate modelling tool”: https://www.edf.org/sites/default/files/US-Natural-Gas-Leakage-Model-User-Guide.pdf ).
HOWARTH. Robert Howarth (41-Nobel-Laureate Cornell University), Dr Drew Shindell (NASA Goddard Space Institute) , Renee Santoro (41-Nobel-Laureate Cornell University), Anthony Ingraffea (41-Nobel-Laureate Cornell University), Nathan Phillips (7-Nobel-Laureate Boston University) and Amy Townsend-Small (University of Cincinatti), “Methane emissions from natural gas systems” (a background paper prepared for the National Climate Assessment 2012): “Methane [the major component of natural gas] is the second largest contributor to human-caused global warming after carbon dioxide … For the 20-year time frame, Shindell et al. (2009) provide a mean estimate of 105 for the global warming potential . Using this value , Howarth et al. (2012) calculated that methane contributes 44% of the entire GHG inventory of the U.S., including carbon dioxide and all other gases from all human activities. Hence, while methane is only causing about 1/5 of the century –scale warming due to U.S. emissions, it is responsible for nearly half of the warming impact of current U.S. emissions over the next 20 years. At this time scale, the methane emissions from natural gas systems contribute 17% of the entire GHG inventory of the U.S,, for all gases from all sources, We repeat that these estimates may be low, and that the gradual replacement of conventional natural gas by shale gas is predicted to increase these methane fluxes by 40% to 60% or more” (Robert Howarth, Dr Drew Shindell, Renee Santoro, Anthony Ingraffea, Nathan Phillips, and Amy Townsend-Small, “Methane emissions from natural gas systems” (a background paper prepared for the National Climate Assessment, reference number 2011- 0003; February25 2012: http://www.eeb.cornell.edu/howarth/Howarth%20et%20al.%20--%20National%20Climate%20Assessment.pdf ).
Dr Robert Howarth ( 41 Nobel Laureate Cornell University) (2015): “Over the past decade, shale gas production has increased from negligible to providing .40% of national gas and 14% of all fossil fuel energy in the USA in 2013… emissions from the natural gas industry, including both conventional gas and shale gas, could best be characterized as averaging 5.4% (±1.8%) for the full life cycle from well to consumer … In June 2015, six of the largest oil and gas companies in Europe including BP and Shell called for a carbon tax as a way to slow global warming.56 An editorial in the New York Times endorsed this idea,56 and indeed, a carbon tax is perhaps the best way to equalize the playing field for renewable energy technologies. The International Monetary Fund estimates that subsidies to fossil fuels globally are in the range of $5 trillion per year, with much of this due to the effects of global warming and consequences on human health.57 A carbon tax would help rectify these subsidies and help promote renewable energy… A carbon tax that adequately addresses the immediacy of global climate change must include both carbon gases. Methane emissions should be taxed using the best available information on methane emissions. And the tax on methane should adequately reflect the importance of methane in current global warming and its influence in global warming over the critically important next few decades. Taxing methane emissions at 86 times the tax for carbon dioxide emissions, using the 20-year GWP from the most recent IPCC synthesis report,2 (Robert Howarth, “Methane emissions and climatic warming risk from hydraulic fracturing and shale gas development: implications for policy”, Energy & Emission Control Technologies, 8 October 2015: https://www.eeb.cornell.edu/howarth/publications/f_EECT-61539-perspectives-on-air-emissions-of-methane-and-climatic-warmin_100815_27470.pdf .)
LAFLEUR. Dimitri Lafleur ( former geoscientist at Shell, PhD student, University of Melbourne) (2016): “With such a vast network and thousands of [CSG] wells, it is very difficult to come up with an accurate number if you don't monitor on a regular basis. And given it is not a requirement to minimise fugitive emissions, why would you? No one knows what the baseline emissions are – from natural emissions from seeps, bores, for example – but I believe there is a chance that these emissions will become larger, with continued [aquifer-depleting] extraction"(Peter Hannam, “”Sleeper issue” of leaking coal seam gas fields may blow hole in emissions goals”, Sydney Morning Herald, 2 July 2016: https://www.smh.com.au/environment/climate-change/sleeper-issue-of-leaking-coal-seam-gas-fields-may-blow-hole-in-emissions-goals-20160622-gpph1q.html ).
PAIGE OGBURN. Stephanie Paige Ogburn (2013): “Say the gas company sends out 100 cubic feet of gas. Some of it might leak out of a pipe and into the soil. Cooling temperatures might make the gas contract, so the meter on the other end reads it as less gas. Some might waft through another leaky pipe out of a manhole or a crack in the asphalt, and into the atmosphere. At the end, only 97 cubic feet get to customers. The missing 3 cubic feet? That's what industry calls "lost and unaccounted for." According to PHMSA, there are two main reasons for this "lost" gas. The first is leaks. The second is measurement issues caused by inconsistent meters or those temperature and pressure variations that cause meters to measure more or less gas, depending on environmental conditions” (Stephanie Paige Ogburn, “How much natural gas leaks?”, Scientific American, 1 August 2013: https://www.scientificamerican.com/article/how-much-natural-gas-leaks/ ).
PANDEY. Sudhanshu Pandey et al. (2019): “Methane emissions due to accidents in the oil and natural gas sector are very challenging to monitor, and hence are seldom considered in emission inventories and reporting. One of the main reasons is the lack of measurements during such events. Here we report the detection of large methane emissions from a gas well blowout in Ohio during February to March 2018 in the total column methane measurements from the spaceborne Tropospheric Monitoring Instrument (TROPOMI). From these data, we derive a methane emission rate of 120 ± 32 metric tons per hour. This hourly emission rate is twice that of the widely reported Aliso Canyon event in California in 2015. Assuming the detected emission represents the average rate for the 20-d blowout period, we find the total methane emission from the well blowout is comparable to one-quarter of the entire state of Ohio’s reported annual oil and natural gas methane emission, or, alternatively, a substantial fraction of the annual anthropogenic methane emissions from several European countries. Our work demonstrates the strength and effectiveness of routine satellite measurements in detecting and quantifying greenhouse gas emission from unpredictable events. In this specific case, the magnitude of a relatively unknown yet extremely large accidental leakage was revealed using measurements of TROPOMI in its routine global survey, providing quantitative assessment of associated methane emissions” (Sudhanshu Pandey et al., “Satellite observations reveal extreme methane leakage from a natural gas well blowout”, PNAS, December 16, 2019: https://www.pnas.org/content/early/2019/12/10/1908712116 ).
RAYNER. Professor Peter Rayner (University of Melbourne) on Coal Seam Gas (CSG) leakage (2016): “[CSG uncertainties] are really very large. It's closer to the surface [than conventional gas] ... it's more dispersed, and the chances for something to go wrong are much higher… [if CSG dirtier than coal] the whole social licence issue is brought into question. It becomes quite serious” (Peter Hannam, “”Sleeper issue” of leaking coal seam gas fields may blow hole in emissions goals”, Sydney Morning Herald, 2 July 2016: https://www.smh.com.au/environment/climate-change/sleeper-issue-of-leaking-coal-seam-gas-fields-may-blow-hole-in-emissions-goals-20160622-gpph1q.html ).
WATERS. Greens Senator Larissa Waters (Deputy Australian Greens leader) (2016): “Coal seam gas and fracking wells and pipes leak like a sieve, and they could be just as bad for the climate as burning coal. As disused gas wells age and concrete casings break down, we risk further leaks for decades to come. No studies have systematically examined the deteriorations of old wells" (Peter Hannam, “”Sleeper issue” of leaking coal seam gas fields may blow hole in emissions goals”, Sydney Morning Herald, 2 July 2016: https://www.smh.com.au/environment/climate-change/sleeper-issue-of-leaking-coal-seam-gas-fields-may-blow-hole-in-emissions-goals-20160622-gpph1q.html ).