Quantifying greenhouse gas emissions from decommissioned oil and gas steel structures: Can current policy meet NetZero goals?

Abigail J. Davies*, Astley Hastings

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


To help achieve global aims to reach Net Zero greenhouse gas (GHG) emissions, a clearly structured method for calculating emissions from decommissioning oil and gas structures is required. In order to understand the GHG consequences of recycling secondary steel from decommissioned structures, this paper presents a new methodology in decommissioning, based on the UN’s International Resource Panel (IRP)’s Value Retention method that combines life cycle assessment principles, the waste hierarchy and the circular economy to holistically calculate GHG emissions produced as a consequence of manufacturing primary and secondary steel, manufacturing a product from this steel and the associated transport emissions. The Value Retention Model presented here combines the concept of material value and product value to obtain realistic GHG emission calculations based on end-of-use and end-of-life scenarios, including recycling and reuse options. The results show that reusing a steel jacket structure in situ will retain55,040 tCO2(eq) in GHG emissions, not including removal operations or transport emissions. New regulation is urgently required to update the current outdated emissions calculation guidelines, enable the provision of both realistic baseline emissions figures and to provide a mechanism for reporting ‘after operations’ figures.
Original languageEnglish
Article number112717
Number of pages13
JournalEnergy Policy
Early online date19 Nov 2021
Publication statusPublished - 1 Jan 2022

Bibliographical note

Funding Information:
This research is funded by OGTC and the University of Aberdeen, through their partnership in the UK National Decommissioning Centre. This work contributed to the NERC funded FAB-GGR project and UKERC-4 projects.

Data Availability Statement

Data available with lead author


  • Circular economy
  • Decommissioning
  • Greenhouse gas emissions
  • Net zero
  • Oil & gas


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