ABSTRACT. MBSA model to evaluate and analyze the production availability of an offshore wind farm

Conference: ESREL 2023.
Session: Energy Transition to Net-Zero Workshop on Reliability, Risk and Resilience - Part III.
Time and place: September 4th, 16:45. Southampton, UK, 3-8 September. Room 100/4011 - Harvard L/TB.

Abstract title: MBSA model to evaluate and analyze the production availability of an offshore wind farm.
Authors: Baptiste Bougoüin, Maïder Estécahandy and Guillaume Clément.

Preparing for the energy transition is one of the major concerns of the French government, which enacted the Energy Transition Law for Green Growth [1] (LTECV) on 17 August 2015 to limit global climate change. To meet this climate challenge, the French energy supermajor Total became TotalEnergies in 2021 to make its company a major player in the energy transition and to achieve, jointly with society, carbon neutrality by 2050.

To achieve this, the company has set itself the following objectives: 1.Reduce greenhouse gas emissions as much as possible, primarily at the sites in Europe and elsewhere in the world for which it is directly responsible. 2.Offset all remaining emissions, for example through CO2 capture projects. 3.At the same time, propose an energy mix that is less and less carbon intensive with the development of renewable energies (solar, hydrogen, onshore and offshore wind, etc.).

To enhance energy mix, from 2022 onwards, new offshore wind farm projects will emerge close to consumption grids and raise new questions which the Offshore Wind industry is preparing for in order to meet the objectives of the LTECV law. To this end, RAM (Reliability Availability Maintainability) studies can help in the decision-making process of the best Operation and Maintenance (O&M) strategy to apply, to obtain an optimum between OPerating EXpenditure (OPEX) and production availability [3] for a given farm.

The complexity of the O&M model of an offshore wind farm relies on the accuracy of the simulation model, especially on the way the weather impact is considered. Indeed, all effects induced on intervention vessel mobilization times, power of turbines and maintenance strategy are to be addressed properly as they can have a significant impact on final results.

In this context, TotalEnergies has taken part into an offshore wind farm project in America North Sea and wants to estimate the production availability of this asset and identify the main contributors to evaluate its O&M strategy and assess the weather impact on its efficiency. To meet this objective, a Model Based Safety Analysis (MBSA ) approach based on Petri nets [5] modeling language combined to Monte-Carlo simulation using the module Flex of the software suite GRIF [6], a technology of TotalEnergies, is under construction. The purpose of this new tool is to consider in a same integrated model (non-exhaustive list):

• Curative maintenance interventions further to random failures,
• Planned events (inspection, preventive maintenance, testing...),
• Weather impact (wind and swell) and all associated effects on the system,
• System architecture and design capacities,
• Logistics (maintenance resources, intervention vessels, mobilization times, spare part strategy, procurement times…).

The objective of this paper is to describe the methodology put in place through a business application case.

References: [1]: https://www.ecologie.gouv.fr/loi-transition-energetique-croissance-verte [2]: DOI:10.3390/jmse10071000 - "Availability Analysis of an Offshore Wind Turbine Subjected to Age-Based Preventive Maintenance by Petri Nets" [3]: ISO 20815:2018 [4]: A Better World of Energy | SSE Renewables [5]: IEC 62551:2012 [6]: GRIF is registered trademark owned by the TotalEnergies Company and used under license, grif.totalenergies.com