Battery powered All-electric, motion-compensated platform system for Offshore CPT testing
Client
Geotechnical Seabed Surveys
The challenge
Our customer specializes in advanced deep penetration CPT for offshore wind farms using advanced CPT systems. To operate efficiently and safely in harsh conditions, they needed a motion-compensated platform that could eliminate the impact of ship movement on seabed operations - while meeting strict offshore classification requirements and reducing environmental impact.
Our solution
DC battery system supplying Active Heave Compensated (AHC) platform lifting winches, umbilical winches and umbilical winches for data communication. The entire system is based on 4 individual units which are operating in AHC and synchronized.
How it works
The system uses an MRU to measure ship motions and counteract the wave-induced movements on the ship. By eliminating the ship motions during touch down of the CPT-rig on the seabed, dynamic forces on the equipment are terminated, as well as working condition for personnel - regardless of ship motion. During compensation, the regenerated kinetic energy is stored in the batteries, reducing energy consumption significantly.
Harmonic distortions
To meet the rules given by the classification societies, the system, which is connected to the ships electrical power distribution system via active front ends (AFE). The Active Front End ensures that the THD (Total harmonic distortions) is kept well below the 5%, required by the classification societies and most importantly making sure that the system is not interfering with other installed equipment on the ship.
Battery system
Benefits:
Results
More operational days
Work continues in challenging wave conditions that would otherwise halt operations.
Significant energy savings
Regenerates up to 60% of energy typically wasted during wave compensation.
Safer operations
No hydraulic oil eliminates risk of marine spills. System operates during black out, protecting equipment.
Major CO2 reduction
Saves 1,100 kg of diesel per day - reducing emissions by 3.3 tons daily (660 tons annually at 200 days/year). These figures are without the fuel savings by only having 1 generator operating instead of 3 because of the peak currents.
Better work environment
During the CPT operation people working with the CPT rods do not experience the ships' relative motions towards the CPT rig as they are standing on an AHC platform and are not exposed to the ship motions when handling the CPT rods. This improves the physical and ergonomic working environment/conditions for the personnel.