This report describes the results of the work of an enlarged Nordic project group in phase II of the RENSEA project. The project was to develop, design, integrate and test a regenerative plugin hybrid-electric propulsion (RPHP) for sail boats. Opal, a whale watching boat used for shorter trips as well as for expeditions at the coast of Iceland and in Eastern Greenland, was used as a case demonstrator for this project.

The driving force behind this project was the vision that a regenerative hybrid-electric propulsion system could dramatically improve the environmental footprint of the boat operation, the economy as well as the customer experience during sailing of boats that operate by both motor and by sail. This could lead to large reduction in greenhouse gas emissions during operations.Of great importance is also is the possibility of using the almost silent electric motor to get closer to whales than with diesel engines, thus enhancing customer experience. The modular hybrid-electric system combines the strengths of an electric drive system (already extensively used in ships), an ideally designed propeller and a modern batterysystem. Regeneration adds the benefit of capturing energy generated from sails during good wind conditions to recharge the batteries.