There are currently 95 Northern Lighthouse Board solar powered land based sites from the north tip of the Shetland Isles to Chicken Rock at the south end of the Isle of Man. Their range varies between three and 23 miles. Lights of less than 15 miles are normally tungsten lamps which are switched on and off by electronically controlled flashers in order to exhibit the advertised character.

The development of high efficiency metal halide lamps has enabled the gas mantles of the Board's automatic long range lights to be replaced by a solar electric system. In the last decade, the power consumption of a typical 18 mile light range has decreased from over 100 W to 35 W. Even in the northern latitudes of Scotland the solar panels, combined with a suitably sized and highly efficient 24 V battery can make use of the diffused light through cloud cover to store sufficient energy to power the light through winter. Supplementary power for monitoring purposes is also supplied by solar.

MJ Information No: 18621