Solar PowerThe Lighthouse Service is constantly seeking ways to make use of renewable energy sources to save money and reduce pollution. For instance,wind energy for heating buildings and wave energy to supply power to buoys are under investigation. The most commonly used source of renewable energy, however, is solar energy.
Solar energy can be transferred into electrical energy directly using a photovoltaic cell. A tiny flake of silicon a few millimetres across will generate an electrical voltage when light falls on it.
Of course, to avoid the reduction in voltage when it is cloudy, or at night, the electricity must be stored in rechargeable batteries. In automated lighthouses, modules of solar cells supply electricity to batteries which in turn supply power to the navigation light, fog signal and other electrical equipment. The condition of the batteries is automatically monitored and controls the amount of current supplied. At Eddystone lighthouse, a series of solar panels have been hung vertically from the helideck.
As well as lighthouses, two unattended light floats, for use in exposed deep sea locations, and an increasing number of light vessels have also been converted to solar power. All lighted buoys have now been converted; solar power replaces dissolved acetylene gas which needed regular and costly refuelling.