Vessel fuel consumption - a comparative case study for offshore product protection methods

The requirements for offshore trenching activities and mechanical protection have recently increased significantly to meet market demands. Inter-array and export cable trenching and backfill activities are expected to rise sharply in the coming few years, due to the increase in construction of renewable energy developments to fulfil ambitious government set quotas. In the meantime, pipeline trenching, mechanical backfilling and rock installation are still taking place within the oil & gas sector during the energy transition. Vessel fuel consumptions associated with offshore wind farm inter-array & export cables and for oil & gas pipelines and umbilicals are examined in this paper. Various aspects that affect fuel consumption such as trenching methods (jetting, ploughing, mechanical backfilling, mechanical cutting and hybrid trenching), rock installation and concrete mattresses installation are discussed and presented, along with areas that can reduce harmful vessel emissions. Case studies are investigated by considering a 10 km pipeline route requiring soil cover, a 10 km umbilical route requiring a lowering specification and a set of typical 2 km inter-array cables complete with a 30 km export cable requiring a lowering specification below a future seabed level.