Original URL: http://www.theregister.co.uk/2007/05/30/suspect_maths/
Westminster blows £29m to save £20k
The suspect maths of energy-saving street lighting
Westminster City Council is doing its bit to save the planet by installing energy-saving street lamps in every thoroughfare in the borough, the BBC reports.
The bold initiative follows a "successful trial" of the £1,000-a-pop Furyo Lanterns on Harrow Road which saved "on an average day", enough juice to light a house for two days and cut carbon emissions on the test highway by 0.28 tonnes over three weeks.
The bulbs in question apparently "reflect light in a much stronger way meaning low wattage bulbs can be used" and boast "solar microchips" which flick on the switch as required, replacing the traditional timer. Councillor Alan Bradley of Westminster Council trumpeted: "Not only will these lights make a significant difference to the environment, but they save money too. These changes are vital and will help preserve our heritage and the city for everyone to enjoy for generations to come."
So far so good. However, the Beeb says that if Westminster replaces all of its 29,000 street lights, it will save "up to £20,000 every year". Since the cost of the new, whale-hugging illumination is £29m, it will therefore recoup its outlay in a mere 1,450 years.
Westminster council says it has "no fixed timetable for installing the lamps", and given the amortisation period on this particular project, we suggest there's no need to rush. ®
Thanks to Nathan Hobbs for the tip-off and doing the maths.