As countries struggle with air pollution from carbon fuels such as coal and vehicle exhausts, they try to find alternative sources of energy. Solar power is becoming widely used in industry, homes and even in transport – a few vehicle carriers have large solar panels on their upper decks to assist with the provision of electricity for the operation of the ship. A suggestion has been made to have a removable, container-sized solar panel atop every slot on containerships. But two main alternative (and importantly renewable) energy sources impact shipping :

Wind Power

Along the coasts of many European countries lie extensive “wind farms”, areas where towers have been built in the sea and along river estuaries to accommodate large wind turbines. The wind turns a propeller-like fitting at the top of the tower; that turns a small turbine to generate electricity. Although the source of the energy (the wind) is renewable, carbon-free and is “free”, some have questioned whether this method of generating electricity is as carbon-free as is claimed. The parts of the towers, wind-generators and links to electricity grids need to be manufactured; the entire towers need to be installed for which either custom-designed ships need to be built or existing ships need to be modified, and regular maintenance can only be done from ships. All of these will leave a carbon footprint.

Tides

In some places, the tidal range is great. This can be used to generate electricity, although it is not used extensively at present. The principle is that the tide will cause a float to rise and fall, a movement that, through gearing can rotate a generator to generate electricity. Another model is that as the tide comes in or goes out, it passes through large pipes in which a series of turbines is positioned, As these turbine turn, electricity is generated.