Propeller efficiency options for green ship

Environmental issues and rising fuel prices necessitate better energy-efficiency in all sectors. Shipping industry is one of the stakeholders in environmental issues. Shipping industry is responsible for 3 % of global CO₂ emissions, 14-15 % of global NO_X emissions and 16 % of global SO_X emissions. Shipping industry also has critical role in global economy since 90 % of world trade goods are carried by ships. This trade has little or no alternate means of transportation other than ships at this point and foreseeable future. In addition, shipping is a better environmental option for transportation compared to other available means of transportation due to lowest gCO₂/ton.km emissions. European Union (EU) and United Nations Framework Convention on Climate Change (UNFCCC) are pushing hard to regulate emissions in all sectors. International Maritime Organization (IMO) is working on regulating emissions from shipping with unprecedented attention and it seems clear that emissions from shipping will be regulated within few years. Furthermore, continuously rising fuel prices are also a reason to focus on new ways for better energy-effectiveness in addition to better environmental performance. Green ship concept requires exploring and implementing technologies/practices on ships to reduce emissions. Propeller efficiency is an important area to increase efficiency and reduce emissions since propellers are merely around 60 % efficient. This paper provides a comprehensive review of the propeller efficiency options to increase efficiency and reduce emissions. The paper will discuss basic concepts and principles, and popular technologies for enhancing propeller efficiency. The author will also comment on the core-issues and challenges, and scope for future development in propeller efficiency area.