Accurate Sizing and Utilization of BESS on Ships with Power-Generating Units Having Weak Load Ramping Capabilities to Improve Fuel Efficiency
Ette, Enobong (2024-08-21)
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2024082266176
https://urn.fi/URN:NBN:fi-fe2024082266176
Tiivistelmä
The maritime industry is undergoing a significant transformation driven by the urgent need to embrace new and environmentally sustainable technologies for merchant vessels. Energy saving with batteries, cost and emission reduction are the main aspects toward the optimum utilisation of the ship’s electric power generation. This transition is a vital goal for meeting international regulations and maritime policies aimed at curbing emissions and enhancing energy efficiency. Battery energy storage system (BESS) plays a significant role in reaching this goal, which helps to improve the overall power generation efficiency. BESS can be used to support the shaft generator (SG) and auxiliary generator (AG) to balance the load, peak shaving and load levelling with optimum operation.
This thesis aims to improve the generation efficiency and operational flexibility of the merchant vessels by applying an optimisation algorithm that allows optimal operation of the battery with SG and AG. The main benefits of utilising batteries in this study were peak shaving during manoeuvring to meet short-time load transients, spinning reserve and load optimisation during normal seagoing conditions instead of starting additional generators to meet the power demand by either charging or discharging, thereby reducing the number of AG starts and stops. Overall, the batteries were used to balance the supply and demand, thus bringing flexibility to the shipboard microgrid (SMG) and improving the loading conditions and fuel efficiency of the generators. This thesis also aims to provide an accurate sizing of the batteries, which reduces the cost and enhances economic and technical benefits. The generator loading conditions and fuel efficiency were improved, leading to reduced fuel consumption.
The outcome of the optimisation was the optimal energy management system (EMS) strategy and optimal battery size. The EMS strategy controlled the economic dispatch of the AGs, SG, and battery utilisation based on the power demand and the cost-effectiveness of the power sources per time. BESS optimisation is valuable as it gives a clue on the minimum battery size to be used. In marine applications, battery utilisation is more effective for dynamic load profiles with transient peaks, as in this case study. Fuel savings achieved were between 1.4% - and 15%, depending on the battery usage and during peak loads, the battery contributed about 27% to the total power required during manoeuvring. Shore power is an expensive option for shipowners due to electricity prices; hence, generating electricity on the ship during harbouring is still preferred except when faced with regulatory demands.
This thesis aims to improve the generation efficiency and operational flexibility of the merchant vessels by applying an optimisation algorithm that allows optimal operation of the battery with SG and AG. The main benefits of utilising batteries in this study were peak shaving during manoeuvring to meet short-time load transients, spinning reserve and load optimisation during normal seagoing conditions instead of starting additional generators to meet the power demand by either charging or discharging, thereby reducing the number of AG starts and stops. Overall, the batteries were used to balance the supply and demand, thus bringing flexibility to the shipboard microgrid (SMG) and improving the loading conditions and fuel efficiency of the generators. This thesis also aims to provide an accurate sizing of the batteries, which reduces the cost and enhances economic and technical benefits. The generator loading conditions and fuel efficiency were improved, leading to reduced fuel consumption.
The outcome of the optimisation was the optimal energy management system (EMS) strategy and optimal battery size. The EMS strategy controlled the economic dispatch of the AGs, SG, and battery utilisation based on the power demand and the cost-effectiveness of the power sources per time. BESS optimisation is valuable as it gives a clue on the minimum battery size to be used. In marine applications, battery utilisation is more effective for dynamic load profiles with transient peaks, as in this case study. Fuel savings achieved were between 1.4% - and 15%, depending on the battery usage and during peak loads, the battery contributed about 27% to the total power required during manoeuvring. Shore power is an expensive option for shipowners due to electricity prices; hence, generating electricity on the ship during harbouring is still preferred except when faced with regulatory demands.