Numerical Simulation of Hybrid Platform Supply Vessel (PSV) Fuel Consumption for the Pre-Salt Layer in Brazil

The new regulations regarding ship emissions based on IMO regulations combined to the high fuel prices require the application of new technologies to improve ship efficiency and to reduce the CO2, NOX, SOX and BC emissions. The application of LNG as fuel and battery packs to improve the conventional engines performance are already a reality in offshore supply vessels (OSV) around the world. However, the reduction in OPEX and payback time of the additional investment is very dependent of the ship operational profile, which are related to the FPSOs and port facilities particularities in Brazil. In order to estimate the advantages of these technologies in the PSV overall performance several different simulators regarding DP operation, sailing, waiting and anchored mode are combined to obtain a digital twin of the vessel. These simulators are combined to the real data monitored from the ships regarding ship speed, position and heading collected in Brazil based on AIS/AIS-Sat database. This database is combined to the environmental conditions regarding wave, current and wind obtained based on global numerical models to provide the environmental loads acting in the ship during the different stages of the operation. The DP simulations are performed applying a thrust allocation algorithm, the calm water resistance is obtained based on regression models and the added resistance due to waves are computed based on strip theory. The forces are converted into electric load by considering the propeller, generators, switchboard, electric drive and engine efficiency curves combined to a power management system (PMS) algorithm, which balance the loads in the engines according to the operational mode. The baseline for comparison is the current PSV without dual-fuel engines or battery pack.