Battery hybrid propulsion

Hybrid propulsion pairs combustion gensets or main engines with a lithium-ion battery on a common DC or AC bus. The battery handles peak shaving, spinning reserve, and zero-emission harbor transits, letting the engines run nearer their best fuel map and cutting start-stop cycling. Marine batteries fall under the IGF Code and class rules such as DNV-RU-SHIP Pt.6 Ch.2, with fire containment, ventilation, and thermal-runaway provisions. Ferries and offshore support vessels are the main adopters; energy density and fire risk limit deep-sea use today.