Methane as a fuel carrier

December 7th, 2021

R&D Focus Areas:
Synthetic fuels and chemicals

Lead Organisation:
CSIRO Energy

Not applicable


Start date:
December 2018

Completion date:
July 2021

Key contacts:
Project Leader: Paul Feron –
Research Scientist: Ali Kiani –

AUD$1,085,553 – Australian Renewable Energy Agency (ARENA)

Project total cost:

Project summary description:
The project has assessed the production of methane as a readily exportable, renewable fuel derived from atmospheric carbon dioxide (Direct Air Capture) and hydrogen produced from renewable sources. The process  entails the capture of CO2 from air using a dedicated amine-solution based process which is integrated with the exothermic methanation process for optimum energy conversion efficiency.

Given the distributed nature of the methane production process the concept has the potential to incrementally replace the production of coal seam gas by renewable methane, using the existing gas collection and transportation infrastructure.

The project addressed the following aspects which are considered critical for further development:

  1. Development of a cost-effective process for energy efficient recovery of carbon dioxide from ambient air with a focus on process and equipment design supported by laboratory-based experiments.
  2. Optimisation of the integration of the carbon dioxide recovery process with the methanation process and the electrolytic hydrogen production process supported by process modelling.

The project has developed an amino-acid salt solution-based process that can effectively capture atmospheric CO2 using commercially available cooling tower equipment. The capture process can be conveniently integrated with the methanation process resulting in zero thermal energy requirement for regeneration of the absorption liquids. The costs to produce synthetic liquefied methane, excluding hydrogen production, were below the target of AUD$10/GJ.

The key findings of the project were:

  • Direct air capture using amino-acid salt solutions is feasible: two amino-acid salt solutions have demonstrated robustness, adequate mass transfer and thermal regenerability that makes them suitable for direct air capture.
  • Direct air capture using liquid absorbents in cooling towers is advantageous: cooling towers, although having a lower mass transfer performance, can be operated at low liquid/gas ratio and have a low pressure drop that result in low energy requirement for the transport of gases and liquids
  • Methanation processes provide significant heat input to the liquid absorbent regeneration process: the process assessment of a leading methanation process integrated with the direct air capture process indicated that the additional heat requirement could be reduced to zero through the inclusion of a vapour recompression process in the liquid absorbent regeneration.
  • Direct air capture cost can be decreased to costs below AU$100/tonneCO2 at a capacity of 1 Mta CO2 :  the project has followed a systematic and staged approach in cost reduction involving adaptation of post-combustion CO2-capture technology to air capture, technology optimisation and integration with methanation and technology scale-up that resulted in a 95% cost reduction compared to the standard amine solution.
  • The cost analysis for the production process of 364 kta liquefied synthetic methane resulted in an overall baseline cost of AU$37.4/GJ at the chosen economic input parameters (interest rate = 8%, project life = 20 years, electricity cost = 60 AU$/MWh): the cost for liquefied synthetic methane was slightly lower than the equivalent liquefied hydrogen production process (= AU$39.3/GJ).
  • Electricity cost were the dominant cost contribution in the production of liquefied synthetic methane: electricity contributed 77% to the overall cost, mostly for the hydrogen production process, indicating the significance of the availability of low-cost electricity. At an interest rate of 4% and an electricity price of AU$30/MWh the overall production cost for liquefied synthetic methane will come down to AU$19.9/GJ.

The technology elements for production of methane using CO2 from the ambient air and hydrogen produced from renewable energy i.e. the direct air capture process and methanation process were concluded to be feasible. Overall, the export of renewable energy as liquefied synthetic methane appears as attractive as export of liquefied hydrogen with the crucial advantage of avoiding large investments in infrastructure for hydrogen transport and utilisation. As such this renewable export pathway will experience much lower physical, logistical, and cost barriers towards introduction because the fuel product remains largely unchanged along the production and export chain. Therefore, it could help smoothen the energy transition towards the use of carbon neutral fuels by providing an alternative route for the export of renewable hydrogen.

Further work will need to be conducted in several areas, both in terms of development of the business case for application and further development of the technology. Our next steps will focus on the establishment of a direct air capture technology demonstrator. Apart from the production of renewable methane, other applications such as production of liquid fuels, chemicals, building products and geological storage of CO2 will be pursued.

Related publications and key links:

  • Techno-Economic Assessment for CO2 Capture from Air Using a Conventional Liquid-Based Absorption Process, Ali Kiani, Kaiqi Jiang and Paul Feron, Front. Energy Res. 8:92, doi: 10.3389/fenrg.2020.00092
  • Liquefied synthetic methane from ambient CO2 and renewable H2 – a techno-economic study, Ali Kiani, Michael Lejeune, Chaoen Li, Jim Patel, Paul Feron, Journal of Natural Gas Science and Engineering, 2021, 104079 (

Conference presentations

  • Direct Capture of CO2 from Ambient Air, Ali Kiani, Kaiqi Jiang, Paul Feron, presented at PCCC5, Kyoto Japan, September 2019
  • A Techno Economic Analysis of Synthetic Methane Production from Ambient CO2 and Renewable H2, Ali Kiani, Michael Lejeune, Chaoen Li, Jim Patel, Paul Feron, presented at GHGT15, 15-18 March 2021
  • Amino Acid Salts for CO2 Capture from Air, Ali Kiani, Ali Pourkhesalian, Will Conway, David Grillmeier, Robert Bennett, Graeme Puxty, Ann-Joelle Minor, Gerard Kluivers, Paul Feron, presented at PCCC6, Virtual conference United Kingdom, October 2021


  • A short video is available on the Ambient CO2 Harvester:

Higher degree studies supported:
Not applicable


December 2021