INSITE Synthesis

Lead Research Organisation: Plymouth Marine Laboratory
Department Name: Plymouth Marine Lab

Abstract

There is an accelerating shift away from oil and gas towards more renewable sources of energy. Many thousands of marine man-made structures (MMS) have been installed to service offshore hydrocarbon and renewable energy industries that provide energy for society. Thousands more structures are being installed to harness the power of the wind. For those MMS approaching the end of their operating life, urgent decisions are required to consider current decommissioning practices, and to support regulatory advice for those that may need to be decommissioned in the future. There are different requirements globally for decommissioning and consensus has not been reached on the optimal environmental outcomes. Aspirations for management systems that support sustainable activity while balancing long-term human and ecological needs, requires scientific consensus on the potential environmental consequences, both positive and negative, associated with the deployment and decommissioning of MMS in the marine environment. This will consider scales from individual MMS to regional seas and encompass ecosystems where MMS exist, from the continental shelves to the deep sea, and from the polar regions to the tropics.
Through a structured process the aim is to develop a view of the current scientific consensus based on the existing evidence base being established under INSITE I and II and other relevant global studies. We will produce a position paper setting out this consensus view on the environmental implications of deploying MMS at scale, leaving non-operational MMS in situ, or removing non-operational MMS. In order to develop and prioritize relevant science questions, we will identify relevant international policy commitments, their associated objectives and goals and the relevance of MMS to their achievement. The focus will be on ecosystem consequences, with a consensus built around the development, and prioritization, of relevant science questions. We will consider the societal consequences of ecosystem changes associated with different choices (including the trade-offs of choices), focusing on ecosystem services and societal goods and benefits. We will make recommendations based on the scientific consensus, and also determine where critical gaps exist in the evidence base.

Publications

10 25 50
 
Description Set out below are a series of statements reflecting the consensus view of the scientists within this project:
• Of all MMS, those related to oil and gas are most important in driving ecological effects, with offshore wind close behind, both individually and regionally. Pipelines and cables are the least important, with artificial reefs and shipwrecks in between. The most important cause of effects is the physical presence of the MMS, followed by hydrodynamics, food availability and contamination. Regionally, connectivity is the second-most important change causing effects. There was less certainty about regional effects compared to local effects.
• Many individual ecological and environmental effects were identified, many of them positive. Most effects would disappear rapidly following removal of the MMS, with the exception of some relating to chemical contamination of sediments. With one or two exceptions there was no consensus that such ecological effects should lead to retention or removal of the MMS.
• Decommissioning decisions should be made pre-installation and making them at the end of operation was the least favoured option. Decommissioning decisions should consider all similar MMS in a region, or groups of nearby MMS. Considering each MMS individually was the least favoured option.
• For a single MMS, repurposing in place was the favoured option followed by partial removal. Regionally, partial removal of some MMS and repurposing or relocating others was the favoured option. Total removal is among the least favoured options, both for individual MMS and regionally.
• Ecological effects should be the most important consideration in decommissioning decisions. Other than ecological effects, the most important consideration was thought to be carbon costs of decommissioning and lifecycle carbon budgets.
• There are major differences in how different regional and local decommissioning strategies support or undermine stated policy goals. Generally, decommissioning and removal is thought to be most supportive of SDG 14 indicators; less so for wider UN goals, and least supportive of OSPAR strategic objectives. Strong differences and trade-offs among decommissioning options in relation to achieving various policy objectives or goals were identified.
• Regionally, and for a single MMS, complete removal was believed to be least likely to achieve OSPAR strategic objectives. Abandonment is generally considered more ecologically beneficial and supportive of stated policy goals than removal or repurposing. Other than abandonment, partial removal for both individual MMS and regionally, was considered to be the option most likely to support achievement of OSPAR objectives.
Exploitation Route We are working to ensure that our findings reach the most appropriate people in the UK and internationally to inform decommissioning decisions.
Sectors Aerospace, Defence and Marine,Energy,Environment,Leisure Activities, including Sports, Recreation and Tourism,Other
URL https://insitenorthsea.org/
 
Description Panel member for INSITE seminar on biodiversity 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The INSITE programme is running a series of webinars for stakeholders to demonstrate to them how the research may be useful in informing their activities. The first one was on biodiversity.
Year(s) Of Engagement Activity 2023
URL https://insitenorthsea.org/