Using a self-contained offshore Wind Turbine Installation Vessel (WTIV) is the preferred method of installation for the main component’s turbine (Tower, Nacelles and Blades). This vessel type, loads turbine components from a port facility, transports them to the installation site, jacks up into positions and performs the installation. In the United States (US), this activity is regulated by the Jones Act; therefore, this vessel will be required to comply with this regulation, including being built, owned and operated by a company from the US.
Currently, there is industry reluctance regarding the ability to build and operate Jones Act compliant WTIV’s due to the extensive costs and delays in delivery.
This alternative WTIV design is tailored for the US Jones Act market:
- Designed with focus on the key elements required for a full but practical functionality to install turbine components in the East Coast of the US.
- Obtained with input from Developers for installations in Europe.
- Designed with consideration of US shipyards build strategies and capacities.
- Based on a proven U.S. operational philosophy.
WTIV Design Basis:
- Minimum Lifting Capacity of 1,100 MT at a 42.5 m radius, based on a NREL 15 MW, upgradable to potential 22 MW with minimum lift capacity of 1250 MT is considered.
- Jacking system for installation operations in up to 60m water depth.
- Dynamic Positioning (DP) system – with DP 2 redundancy level and environmental conditions established for the Northeast Coast of the US:
- 35 Knots – Wind
- 2 m – Hs
- 1.4 Knot Current
- Cargo deck capacity to accommodate a minimum of 3 x 15 MW NREL ref turbine.
- Accommodations to support 60 working crew.
This design will incorporate basis lessons learned from successful US building programs including:
- Incorporating simple design techniques from similar vessels already built and operating in the US.
- Vessel hull and hull modules designed with consideration of US shipyard capabilities.
- Critical components such as Jacking System, which is developed in collaboration with companies with experience in fabricating Jacking Systems.
- Consensus from Class and Flag on the applicable rule and regulations.
- Detail Engineering including Class approvals prior to beginning construction.
- Design development cooperation with the various stake holders. This has proven to be a successful model within the US shipbuilding industry.
- The WTIV is designed to work in conjunction with a workboat in coupled configuration for transiting from and to sit.
- This workboat would also serve as a Service Offshore Vessel (SOV), fitted with accommodations and walk to work heave compensated gangway.
- The connection is through a proven Coupler System currently utilized in the US Flag ATB industry.
- The WTIV will be self-positioning with a DP 2 system once onsite.
- The WTIV will be fitted with state-of-the-art accommodations to house industrial personnel required for the installation operation.
The NETSCo case study was created as a Poster Presentation for ACT Offshore Windpower Conference 2022. For more information about this or other offshore wind turbine projects at NETSCo contact Jan Flores at firstname.lastname@example.org