Session: 09-01-14 Fatigue and Structural Analysis

Paper Number: 79598

79598 - Sustainable Reuse of Decommissioned Jacket Platforms for Offshore Wind Energy Accounting for Accumulated Fatigue Damage 

Accelerating the offshore energy transition from carbon-emitting fossil fuel extraction to sustainable clean sources is urgent if we are to slow the harmful impacts of climate change.  Ocean-based renewable energy such as from wind, current, tides and waves can be key in this endeavor.  A large number of jacket platforms that have supported the offshore oil and gas industry are reaching the end of their useful lives.  The potential for sustainable reuse of decommissioned offshore jacket platforms has emerged as an attractive proposition in this transition period in offshore energy generation.  The green premium – namely, the additional cost of choosing a clean technology over one that emits a greater amount of greenhouse gases – can be dramatically reduced by reusing existing offshore jacket platforms.  To maximize the benefit of reuse, we need an optimized plan that accounts for the remaining life of the repurposed platform, , the overall construction and platform retrofit cost, and an expectation of a period of the gross clean energy generation after the wind turbine installation.  This study formulates a fatigue reliability-based framework to aid in this sustainable reuse planning and optimization.

The proposed framework involves a fatigue reliability analysis to assess the remaining life of an existing platform.  Metocean statistics considering wind and wave conditions at the candidate site are considered in fatigue assessments for various sea states.  Stochastic wind field and wave  time-domain simulations followed by aeroelastic and hydrodynamic response simulations are carried out on the integrated platform-turbine systems.  Rainflow-cycle counting is employed to output stress time series in fatigue damage assessment.  Classical reliability analysis can then be performed for different periods of reuse of the platform with the installed wind turbine.  For the choice of wind turbine, we consider various options with different associated power ratings and dimensions.  An optimization problem is defined considering large turbines with higher ratings but possibly shorter expected service lives as well as alternatives.  The same fatigue reliability analysis is employed with all the reuse options.  The end goal is to establish an optimal plan that considers the life cycle, energy generation revenues, and overall construction costs.  We will employ a realistic case study and sustainable reuse scenario for a site in Porto, Portugal.

 

Presenting Author: Taemin Heo The University of Texas at Austin

Authors:

Taemin Heo The University of Texas at Austin
Ding Peng Liu The University of Texas at Austin
Lance Manuel University of Texas at Austin
Jose Correia University of Porto
Paulo Mendes University of Porto