Yacht hybrid propulsion technology is the use of two (or more) different energy sources for propulsion, where the traditional energy source is supplemented by another power source. Most often, this means using a combination of diesel and electric systems.

The details

Traditionally, yachts are powered by an internal combustion engine that runs on fuel. In contrast, an all-electric propulsion system uses a battery-powered engine. A hybrid propulsion system uses a variable combination of internal combustion engine, generators, battery packs and electric motors, depending on the system.

Parallel hybrid system: 

This versatile system offers multiple options for operation and allows the user to easily switch between drive modes (whether electric or combustion engine). Unlike the serial hybrid drive, in a parallel hybrid system the motor and drive shaft are directly connected, with the electric motor acting on the same drive shaft. In this concept, the conventional engine is retained if it needs to be operated for a longer period of time. The electric system can then be used as needed, depending on the settings/conditions/requirements, with both systems operating in parallel.

Since the generator/electric motor is not directly connected to the propeller shaft, the serial system must be capable of delivering the highest propulsive power the boat can achieve and therefore must be more powerful than a parallel system. While a serial hybrid system offers a significant improvement in efficiency (over a conventional system) at higher or optimum speeds, this setup can also lead to situations where the efficiency benefits of the hybrid system are potentially reduced at low speeds, such as when maneuvering in port.

In contrast, the electrical elements of a parallel system do not have to operate at such high drive powers. The conventional motor can be used for higher speeds, while the electric motor is generally used when low to medium speeds are required. The conventional motor is usually used at higher speeds and/or when the batteries are empty, i.e. the most efficient operating mode is initiated as required.

Read more about the innovative hybrid drive of the Bering B145 here: https://www.danfoss.com/en-us/about-danfoss/news/dps/danfoss-editron-delivering-hybrid-propulsion-system-for-new-superyacht/