A novel framework for sustainable decision-making on reusing Oil & Gas offshore platforms with application to the Adriatic Sea

Many Oil and Gas offshore platforms will likely end their operational life in the near future and enter a decommissioning phase, which is a relevant process from both an economic and environmental viewpoint. As an alternative to decommissioning “as is”, these platforms could be optioned for repurposing to support different economic activities, a. o. energy, tourism, aquaculture, transportation, greenhouses. This paper presents a methodological framework to facilitate the identification of the repurposing activities and the decision between reuse and decommissioning of Oil and Gas platforms. The selection of the most promising combination of reuse activities is performed through a multi-criteria assessment, while the decision between reuse and decommissioning consists of the quantitative evaluation of the sustainability of the reuse, based on economic, social and environmental Key Performance Indicators. These indicators represent the most significant issues posed by the reuse such as the creation of new jobs, investment and operation costs, production, marine footprint, CO2 reduction, social awareness of ecosystem services. The relevance of the responsibility of the decommissioning cost in case of reuse is also discussed. This new framework is applied to an Oil and Gas platform in the Northern Adriatic Sea, Italy, in a hypothetical decommissioning scenario. The results of this application show that a large marine area would be required to make the reuse a sustainable alternative to decommissioning.