Last Updated: Apr 2012
What is it?
Renewable energy is energy generated from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are naturally replenished. The most popular renewable energies being tested by the shipping industry are solar and wind. While wave energy is being explored, this is closely related to new ship designs.
How it works
Shipping has been testing solar panels, which are large flat panels made up of many individual solar cells, to collect sunlight and convert it into electricity. Solar cells, known as photovoltaic (PV) cells convert light into electric current using the photoelectric effect.
Up until recently the energy from solar panels has been harnessed for the crew's living quarters. However, as the technology develops the industry has been harnessing the power to partially power a ship's propulsion engine.
There are a number of wind technologies that are being tested, including wind ships which have a optimised rig for sailing upwind, a towing kite for ships, wind turbines, and wind engines.
The towing kite consists of simple components including a kite with a rope, a launch and recovery system, and a control system for automatic operation. It is deployed from a retractable mast on the ship's deck and controlled by a central console that monitors the kite to maintain its optimum position. Kite power means the ship's engines can work on reduced power, lower fuel consumption and emissions.
Wind turbines are rotating machines that converts the energy of wind into kinetic energy. The wind engine, developed by UK-based environmental non-profit organisation Greenwave, uses a technology that was originally developed in the 1920s known as the Magnus effect. It contains a vertical cylinder which spins when it comes into contact with wind. This creates a very low pressure on one side which generates lift and thrust in a similar way that a sail does.