<
https://reneweconomy.com.au/exporting-gas-can-more-than-double-the-emissions-compared-to-using-it-in-australia-so-why-are-we-doing-it/>
"There is a new article from Cornell University that suggests that the
emissions associated with the export and use of liquefied natural gas (LNG)
from shale gas in the United States are higher than burning coal. Although this
will be no great surprise to those who take an interest in this issue, there
are two aspects of the research that are important contributions to the debate
in Australia.
The first of these is the application of a 20-year Global Warming Potential
(GWP) for methane, rather than the normally used 100 year value. The concept of
the GWP to compare the emissions impact of different greenhouse gases (GHGs)
goes back to decisions by the Intergovernmental Panel on Climate Change (IPCC)
in the nineties.
There are two aspects to calculating the GWP of GHGs – their ability to absorb
energy and the duration they remain effective in the atmosphere. Because these
differ between gases GWP was invented as a way of comparing methane and other
GHGs to CO₂, giving rise to the “CO₂ equivalent” (CO2e) values conventionally
used.
The time period usually used for non-CO₂ gases is 100 years, which probably
seemed appropriate back in the 1990s. Methane (CH₄) however, is a much more
potent GHG than CO₂, albeit with a shorter lifetime in the atmosphere.
When measured on (say) a 20‐year period it has more than 80 times the effect of
CO₂. In the midst of a climate crisis and a race for net zero emissions by
2050, clearly a GWP20 is more appropriate than GWP100. The use of GWP20 leads
to increased CO2e values for methane of 82.5 instead of 29.8.
The second aspect of the research which is relevant is the more accurate
capture of fugitive emissions from shale gas operations in the US from airborne
methane surveys which identify major gaps in official estimates.
Australia’s National Greenhouse Gas Accounts report that fugitive emissions
(from all sources) are around 11% of the total. A recent report from the Future
Energy Exports Cooperative Research Centre states that reported fugitive
emissions from the oil and gas sector were 21 MtCO2e in 2021 or around 20% of
the national total.
However, a new report using the Open Methane mapping approach by the Superpower
Institute identifies that methane emissions are likely to be around twice that
reported for 20 coal and gas sites (which don’t include offshore gas projects).
There is global concern about under-reporting of methane emissions, leading to
Australia joining the Global Methane Pledge working to reduce “methane
emissions across all sectors by at least 30% below 2020 levels by 2030”."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
