Greenhouse gas emissions reduction and energy savings for a dredger at port area using hybrid photovoltaic power system onboard

Abstract

For reducing greenhouse gas (GHG) emission and saving energy, a hybrid photovoltaic (PV) energy system comprised of grid-connect and off-grid modes was utilized on a dredger at emission control area (ECA) such as a port area. The experiments on this hybrid PV power system were carried out to evaluate the electric energy consumption of each equipment onboard in three operation modes (dredging, rest and idle) of dredger and to analyze the contribution of such a PV power system. The PV array had charging batteries in grid-connect mode and converted the PV power to alternating current (AC) directly during daytime period. At nighttime, the batteries could supply the electric power in off-grid mode. Even this dredger is no large free deck area for installing PV arrays onboard, the power conversion for PV array can offer about 1.0 % of total demand electric energy yearly. After evaluating the electric power consumption of each equipment onboard at different dredger operation mode, the proposed hybrid PV power system can offer 4.0 % (3.9 kWh by 96.8 kWh) of energy demand in grid-connect at rest mode and supply 100 % (29.85 kWh by 29.85 kWh) energy for dredger equipment in off-grid without diesel generator running at idle mode. This hybrid PV power system on the dredger has not only saved marine diesel oil (MDO) 2094.2 kg/year, reduced GHG of CO2 about 6455 kg/year, SOx about 3.942 kg/year and particulate matter (PM) around 1.97 kg/year but also reduced the diesel generator maintenance cost from stop running for 15 h/day and saved the cost of fuel (MDO) about USD 2128.5/year. The hybrid PV power system exhibited very effective efficiency of PV array and optimized the installation of batteries bank in ship with limited deck space at ECA and port area with high solar radiation density zone.