In North America, the  energy spent in uselessly lighting up the sky costs about a billion dollars each year.  This is a pure waste of energy that also  increases greenhouse gas emissions when fossil fuels are used to produce the  electricity, which is generally the case.

Here in Quebec,  more light is produced per inhabitant than anywhere else in the world.  It has thus been estimated that 700 GWh  could be saved annually in this province by improving lighting management.  This amount of energy represents the annual  electric heating bill for about 20,000 homes.   All this waste costs over 50 million dollars per year!