ELECTRIC PROPULSION AND CHARGING
Growth in the amount of full electric and hybrid vessels has brought up the importance of fast charging in addition to the rapid charging connection after vessel is moored. Extra weight and cost of batteries onboard has to be minimized as well as the mooring time.
Due to this, either current or voltage, has to be in high level to keep the charging effective i.e. optimized time wise. In alternating current (AC) systems the voltage is extremely high over the charging connection whereas in direct current (DC) systems the current is high.
Difference – in other words benefits or losses – between AC/DC charging connectors is if the quay or ship side needs to be simple and light. In AC-systems the quayside can be built simple and cheap. DC-systems are more cost-effective and lighter for the ships.
Criteria of evaluation can depend on: how many ports vessel has to visit, which are the grid limits onshore, does the vessel size or speed allow carrying weight from transformers, rectifiers and chargers onboard.