Saturday, September 17, 2022

Natural gas, Methane emissions reduction and the need to implement methane removal

Image: large scale methane removal possible via atmospheric solar photocatalysis wind chimney

What was I doing at 4am on a Friday morning? Watching a Methane Action (US NGO) organised webinar (1) on methane reduction and methane removal.

This webinar had Sir David King, a former chief scientist for the UK, doing a presentation. I first came across Sir David King's statements on the approaching climate crisis around 2004.(2)

Speakers included:

Rob Jackson – Stanford University professor and Global Carbon Project chair
Renaud de Richter — Science Advisor, Methane Action
Durwood Zaelke – President, Institute for Governance & Sustainable Development
Wil Burns –Northwestern University visiting professor, previously founding co-director of American University’s Institute for Carbon Removal Law & Policy
Zerin Osho — India Climate Law and Policy Adviser, Institute for Governance & Sustainable Development
John Fitzgerald — Legal Counsel, Methane Action
Daphne Wysham — CEO, Methane Action
VIDEO: Methane Removal:  On the Critical Path to Reducing Peak Global Temperatures

Methane is a key greenhouse gas that is increasing in the atmosphere. Because it's Global Warming Potential (GWP) impact on short time scales (12 years) is high (at least 86 times that of carbon dioxide), it is an important gas to address for near immediate effect that can buy us much needed time while we address carbon dioxide emissions and removal.

It is important to address methane emissions in the three key sectors of agriculture, landfill waste, and fossil fuel extraction. Each needs a separate plan for emissions reduction.

Need to reduce Natural Gas consumer use

Of course Natural gas is essentially methane. So at the business and consumer level it is important to phase out the use of natural gas. 

Methane fugitive emissions occur at all stages of production, processing, transport and use. Conversion of gas use in space heating, hot water systems and cooking need to be all electrified.

Over 120 countries have now signed the Global Methane Pledge to cut methane by at least 30% by 2030.(3)

My thoughts on Global Methane Pledge and Australia process:

Australia has not yet signed, but this is under serious consideration by the Albanese Government.(4)

COP27 at Sharm El-sheik in Egypt might provide a good platform for an announcement in late November 2022.

  1. Albanese government needs to update the National Greenhouse Gas Emissions reporting methodology for methane to ensure accurate reporting that correlates with remote sensing satelite observations. Currently the IEA estimates Australian methane emissions are double what we are reporting to the UNFCCC.
  2. Sign the Global methane Pledge
  3. Set up sectorial methane reduction plans for Fossil fuel fugitive emissions and ensure polluters implement reductions (regulation), address agricultural and animal husbandry emissions (CSIRO are already working on this with Meat and Livestock Australia), address emissions from waste landfill. Each sector needs a tailored plan of action.

It is not necessary that each sector reaches a 30% reduction, but a combination of all the sectorial plans should meet or exceed an Australian target as part of signing the global methane pledge target.

Implementing large scale Methane removal important

The importance of the Methane Action webinar was the emphasis that we need to start considering methane removal from the atmosphere as well as methane reduction.(4)

There are a number of options/possible technologies for methane removal. Some of these can also be incorporated alongside CO2 Direct Air Capture technologies.(5).

Removal at scale of some of these gases would also contribute to reducing atmospheric pollutants and increasing population health.

The Removal of non-CO2 greenhouse gases at scale, including Nitrous Oxide, methane, ozone, CFCs, by large-scale atmospheric solar photocatalysis looks promising. This involves solar chimneys that generate an airflow that power turbines producing renewable energy. The area around the solar chimney would be like a giant tent with treated walls and ceilings that would cause reaction by non CO2 greenhiouse gases in UV light.

Pilot plants have tested the feasibility, but the technology needs to be scaled up and implemented. (6) (See image of how large-scale atmospheric solar photocatalysis works)


(1) US Methane reduction and removal webinar Friday 16 Sep 2022

(2) TUESDAY, OCTOBER 26, 2004 Kyoto is not enough says UK Chief Scientist, while Australia sticks with the USA

(3) TUESDAY, SEPTEMBER 28, 2021 Global Methane Pledge aims for 30 percent methane emissions cut from 2020 levels by 2030

(4) Albanese government may join US push to cut global methane emissions by 30% (23 June 2022)

(5) Recent assessment of removal of methane. Tingzhen Ming, Wei Li, Qingchun Yuan, Philip Davies, Renaud de Richter, Chong Peng, Qihong Deng, Yanping Yuan, Sylvain Caillol, Nan Zhou, Perspectives on removal of atmospheric methane, Advances in Applied Energy, Volume 5, 2022, 100085, ISSN 2666-7924,

Abstract: Methane's contribution to radiative forcing is second only to that of CO2. Though previously neglected, methane is now gaining increasing public attention as a GHG. At the recent COP26 in Glasgow, 105 countries signed “the methane pledge” committing to a 30% reduction in emissions from oil and gas by 2030 compared to 2020 levels. Removal methods are complementary to such reduction, as they can deal with other sources of anthropogenic emissions as well as legacy emissions already accumulated in the troposphere. They can also provide future insurance in case biogenic emissions start rising significantly. This article reviews proposed methods for atmospheric methane removal at a climatically significant scale. These methods include enhancement of natural hydroxyl and chlorine sinks, photocatalysis in solar updraft towers, zeolite catalyst in direct air capture devices, and methanotrophic bacteria. Though these are still at an early stage of development, a comparison is provided with some carbon dioxide removal methods in terms of expected costs. The cheapest method is potentially enhancement of the chlorine natural sink, costing as little as $1.6 per ton CO2-eq, but this should be carried out over remote areas to avoid endangering human health. Complementarity with methane emissions reduction is also discussed.

Keywords: Methane removal; Photocatalysis; Chlorine atoms; Hydroxyl radicals; Zeolites; Methane mitigation; Methane remediation; Enhanced atmospheric methane oxidation

(6) See also: Renaud de_Richter, Tingzhen Ming, Philip Davies, Wei Liu, Sylvain Caillol, 'Removal of non-CO2 greenhouse gases by large-scale atmospheric solar photocatalysis',
Progress in Energy and Combustion Science, Volume 60, 2017, Pages 68-96, ISSN 0360-1285,

Abstract: Large-scale atmospheric removal of greenhouse gases (GHGs) including methane, nitrous oxide and ozone-depleting halocarbons could reduce global warming more quickly than atmospheric removal of CO2. Photocatalysis of methane oxidizes it to CO2, effectively reducing its global warming potential (GWP) by at least 90%. Nitrous oxide can be reduced to nitrogen and oxygen by photocatalysis; meanwhile halocarbons can be mineralized by red-ox photocatalytic reactions to acid halides and CO2. Photocatalysis avoids the need for capture and sequestration of these atmospheric components. Here review an unusual hybrid device combining photocatalysis with carbon-free electricity with no-intermittency based on the solar updraft chimney. Then we review experimental evidence regarding photocatalytic transformations of non-CO2 GHGs. We propose to combine TiO2-photocatalysis with solar chimney power plants (SCPPs) to cleanse the atmosphere of non-CO2 GHGs. Worldwide installation of 50,000 SCPPs, each of capacity 200MW, would generate a cumulative 34PWh of renewable electricity by 2050, taking into account construction time. These SCPPs equipped with photocatalyst would process 1atmospheric volume each 14–16 years, reducing or stopping the atmospheric growth rate of the non-CO2 GHGs and progressively reducing their atmospheric concentrations. Removal of methane, as compared to other GHGs, has enhanced efficacy in reducing radiative forcing because it liberates more °OH radicals to accelerate the cleaning of the troposphere. The overall reduction in non-CO2 GHG concentration would help to limit global temperature rise. By physically linking greenhouse gas removal to renewable electricity generation, the hybrid concept would avoid the moral hazard associated with most other climate engineering proposals.

Keywords: Atmospheric greenhouse gas removal; GHG photocatalysis; Solar-wind hybrid; Negative emissions technology; Solar chimney power plant; Giant photocatalytic reactor; Large scale atmospheric air cleansing

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