By Chris Kipp
The two most abundant greenhouse gases (GHGs) in the oil and gas industry are carbon dioxide (CO2) and methane (CH4). One way to look at GHGs and create an equal comparison is with a carbon dioxide equivalent (CO2e) base This equation normalizes the ability of a molecule to trap heat in the atmosphere to that of CO2 molecule, using a global warming potential (GWP) factor. The US primarily uses 100-year GWP as a measure of the relative impact of different GHGs resulting in a GWP factor of 25 for CH4. In 100 years, 1 tonne (0.9 tonnes) of CH4 emitted would have the same warming potential as 25 tonnes (22.7 tonnes) of CO2resulting in this equation:
Co2e = CO2 + (CH4 × 25) + others
However, CH4 molecules break down much faster in the atmosphere and have a higher impact on short-term global warming; therefore, other metrics have been developed to compare one GHG to another. For example, the 20-year GWP is sometimes used as an alternative to the 100-year GWP; the 20-year GWP is based on the energy absorbed over 20 years. Since all GWPs are calculated relative to CO2GWPs based on a shorter time period will be larger for gases with shorter lifetimes than CO2and smaller for gases with longer lifetimes than CO2. Using the 20-year GWP results in a GWP factor for CH4 several times higher than the 100-year GWP.
CH4 emissions have become an important topic with an increasing number of industry conferences focusing strictly on CH4 mitigation The CH4-Focused conferences typically consist of oil and natural gas producers presenting and demonstrating the technology used to capture all vented CH.4 and reducing all possible sources, sometimes exceeding current regulations. This is a benefit from a public perception perspective and benefits investors, shareholders, communities, as well as the entire oil and gas industry. By responsibly producing oil and natural gas today, the industry is helping to pave the way for a strong future.
What are the typical emission sources and where does the CO come from2 and CH4 do the emissions originate at a compression station? Co2 Emissions are almost directly correlated to the amount of fuel burned on site, with the largest sources being engines or turbines and the smallest sources being heaters. CH4 emissions are more complicated to measure and are emitted in two different ways: from vented or leaky sources and through engine tailpipes. the company2The footprint of a typical lean burn compressor station, from the engine exhaust and vented CH4it comprises 67% CO2 and 33% CH4 using the 100-year GWP. the company2 emissions come almost entirely from the engine exhaust, while the CH4 emissions are split almost equally between unburned CH4 to the engine exhaust and CH4 of leaks and ventilations. With the main sources identified, production companies can target reductions in these specific areas.
The Inflation Reduction Act (IRA), signed into law on August 16, 2022, includes some provisions related to CH4 emissions affecting the oil and gas industry. IRA Section 60113 adds Section 136 to the Clean Air Act, imposing the first direct “charge” on… Click here to continue reading this article in the April 2023 Digital Issue Gas Compression Journal.
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