Work Package 6
Lifetime offshore logistics
Objective: To reduce uncertainty on, and optimise, risk and cost of offshore operations.
In offshore wind OPEX is roughly a third of cost of energy, of which offshore operations typically is the major contributor. Offshore operations also have a major impact on Life Cycle CO2 emissions. Although similar importance is expected in wave energy farms, the lack open-sea experience shared across the sector introduces major uncertainty on expectable OPEX in wave farms, which introduces a costly business risk in wave energy projects. Documenting and sharing information on offshore operations in OPERA is a major opportunity to achieve decisive progress on this front.
This Work Package focuses on lifetime offshore logistics of floating OWC with a goal to reduce the uncertainty on, and optimise, the risk and cost of offshore operations.
For these purposes, this Work Package will:
- Improve operational models to more precisely reflect logistic requirements for floating OWC
- Identify and optimise maintenance and operational procedures to lower life-cycle costs
- Perform, improve and document required offshore operations during the open-sea testing period
- Provide figures for OPEX calculation based on real open sea operations
- Produce guidelines and recommendations that minimise risk and cost of offshore operations for wave energy
Task to be performed
Logistics needs characterisation
- Detailed inventory of offshore operations needed
- Hazard identification, risk assessment and mitigation actions
- Planning and scheduling of maritime operations
- Required functional and operational specifications of vessels/equipment and competences of key people
- Weather window thresholds for the various marine operations depending on the vessel, HSE and activity being performed
- Applicable codes, standards, legislation and recommended practices (including environmental issues)
Installation includes on-site port activities before the device is deployed at sea, device towing, heavy lifting or submerging, ballasting, securing to the seabed and connection to the grid. Apart from the device itself, installation operations will also encompass wave resource instruments, mooring, and turbine, generator and power electronics. Operations will comply with bimep procedures and international regulations.
The inspection, repair and maintenance levels/frequency will be adjusted to the reliability considerations of the prototype and the limitations on weather windows accessibility to the site, including provisions for emergency situations. Unscheduled maintenance actions will be simulated in order to reduce risks and estimate realistic operating costs. In-service inspections and small repair will be done onsite, whereas large maintenance actions will be done at Bilbao port. Decommissioning operations and costs will be considered with attention to the expected duration of a commercial project and its consequences on the lifetime cycle.
Improve offshore logistics and cost models
The operational model in this work package will be focused on the cost of offshore operations, whereas the cost of components to be replaced and other running costs such as insurance will be integrated in the overall cost model in WP7. The task will also collect information from all the other WPs on the probability of failure and the need for replacement of the equipment on board. Results will be used to feed into operational models for the OPEX calculation and O&M scheduling and will be validated against the effective failures and replacements occurring on site.
Modelling site accessibility assessment with estimation of weather windows and validation against real sea operations is also necessary to realistically assess the waiting time and costs. The analysis of maritime strategies will be completed using models for the operational simulation of offshore renewable devices when it is not possible to gather this information directly from the open-sea experience (limited to a single unit). These tools might include optimisation methods and techno-economic analysis to aid in the decision making and will be validated against the case offered by the real sea operations at bimep.
Monitoring of safe offshore operations and logistics
The plan of offshore activities developed in the first task will be compared with the real operating experience. Detailed monitoring and recording will be used to systematically identify opportunities for better specifying required vessels, diver and equipment, dock and crane, and necessary weather windows. The planning of offshore operations will be continuously updated with this information and the reduction in uncertainties achieved from open-sea implementation recorded to be used for final project assessment by WP7. Subcontracting to vessel/equipment and qualified personnel will follow standard offshore procedures and practice with the constant concern and record to identify specific requirements for wave energy as well as specific opportunities for cost-reduction.
Recommendations and guidelines
Where they are important, these newly de-risked specifications for wave energy shall be compared to relevant offshore oil & gas requirements, which still guide maritime operations in ocean energy despite presenting fundamentally different risks to human life and the environment. The offshore logistics experience will be extrapolated to different scenarios of larger deployment using state of the art methods and in particular the wave farm design tools developed by the H2020-DTOcean project, with a view to better assess economies of scale and identify logistics bottlenecks when deployed in large arrays.