Background
Optimization and design of shore to ship charging Systems for all-electric and plug-in hybrid ferries
Electrification of marine vessels has become an important and efficient solution for moving toward the zero and low-emission sea transportation. Existing technologies for reducing emissions include diesel-electric, hybrid and fully battery-electric propulsion systems. While hybrid or plug-in hybrid propulsion systems can reduce the consumption of fossil fuels, fully battery-electric solutions can eliminate all emissions from regular operation. Hybrid propulsion systems allows for onboard batteries to be recharged by diesel generators or discharged to supply peak loads. Furthermore, another way to recharge the onboard batteries is shore charging which can allow for sustainable energies, such as wind, solar and hydropower energies available in onshore power systems to be utilized for propulsion in the onboard power system. Often, the electricity generated on land is also cheaper and more sustainable than the electricity generated by onboard diesel engines. The main challenge of using batteries in maritime vessels is their low energy density. In other words, a marine battery pack which weighs about tens of tones and spaces hundreds of square meters cannot guarantee the propulsion power for long distances. Thus, due to the current range limitations of marine batteries, they are often installed on short-distance and coastal ferries. With tight schedules for short-distance ferries, it is important to take advantage of docking time efficiently, introducing the need for fast charging. Another challenge of shore-charging systems for motor/car ferries is that usually the ports are located in remote areas with limited capacity in the local power grid. This means that the local grid may not be able to provide high power demand for fast charging. To overcome this challenge, stationary energy storage systems are used as energy buffers and to support the weak grid during the charging. However, these stationary batteries introduce other challenges such as the excessive energy loss and reliability of multiple battery systems. Therefore, energy efficiency and reliability have to be taken into account in the design phase.
Scope
- Power system architecture of solutions for shore-to-ship charging systems (S2SCS); wired AC and DC as well as inductive charging.
- Energy efficiency evaluation of S2SCS solutions, so-called, “grid-to-propeller energy efficiency".
- Reliability assessment of S2SFBC in terms of charging load curtailment index. Cost-based redundancy design of the S2SCS.
- Control and operation management of S2SCS.
Applications
- For charging all-electric and hybrid ferries
- Smart ports facilitating shore charging
Achievements 2021
- Published an article about the reliability assessment of shore-to-ship charging and its impact on the design in IEEE Transactions on Transportation Electrification.
- Hosted a webinar for smart maritime on “To-ship power transfer for sustainable propulsion”.
- Established a novel power architecture as universal multi-vessel shore-to-ship charging system.