The Economic Cost of light pollution
(see also our Cost Calculator)
£110 M | On average, 30% of the light from a streetlight shines upwards and outwards. The light wasted by the UK's 9 million streetlights costs £110 million a year in electricity bills (see below for more details). |
£36 M | There are 22 million homes in the UK. If just one in ten has a 500W 'security' floodlight, which is activated for just 1 hour per night, the sum cost is £40M. Since a 50W bulb is sufficient for most domestic applications, the total cost of wasted electricity is £36M. |
£880 M | Assuming that there are twice as many floodlights used in commercial situations that domestic (floodlighting warehouses, supermarkets, churches, bus stations, etc), and that these lights are on all night throughout year. |
Total>£1 bn | The total of the above. All these figures assume the cost of electricity to be 10p per kW hr. Please feel free to check these figures using our Cost Calculator. |
Considering street-lights alone...
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This calculation is based on £52 million being wasted in 1994 UK wide (ref. Light Pollution: Responses and Remedies, by Bob Mizon), and increasing at an assumed constant rate of 6.4% per year - 3% from inflation (source: National Statistics) and 3.4% from increasing light pollution (24% in 7 years source: CPRE).
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Economics is why...
If water were leaking from a tap, it would be repaired promptly to avoid
wasting money. Why isn't the same action taken for a leaking light?
The equivalent of over 2 power stations' worth of electricity (and
pollution) are wasted as light pollution.
In Britain alone, over £100 million worth of electricity is wasted per year from inefficient streetlights alone (see above). Over 30% of the light from an average street-light never actually hits the street - 30% of the light generated, equivalent to £52 million a year (as of 1994), is simply wasted!
And this number is rising rapidly. Light pollution has increased by 24% in just 7 years (see the CPRE website). According to the BBC News, the cost of electricity has risen by 14% in the last year (2003-2004). So, to get these numbers in terms of todays prices, we should also include inflation at about 3% per year. Hence, £52 million a year in 1994, becomes at least £100 million pounds of wasted light per year in 2004, at a very conservative estimate, from street-lights alone.
In Leicester alone (population about 300,000), about 5 million kilowatt hours per year are going directly to light up the night sky. This means that 5 million kg, or 5 thousand tonnes, of CO2 are generated per year to do this. That's about 14 tonnes per day for Leicester alone (A so-called "Enviromental city"!).
5 million kWh of wasted energy per year, is a rate of wasted energy of 1.1 megawatts. This translates into the energy generated by a couple of wind turbines.
If Leicester is typical of the UK, this adds up to about 450 windmills.
Not only does this highlight how large amounts of money can be saved, but it will also reduce carbon dioxide emission from coal-burning generators.
This vast amount of money that is wasted was the primary motivation why the City of Calgary (Canada) decided to replace all their streetlighting with efficient lights - the newer light fittings will save the city $2 million a year! This money is saved by using lower powered bulbs - you might think that this would resulting in darker streets, but since the new light fittings ensure that 100% of the light produced is directed towards the streets and that no light is wasted, the night-time brightness of the streets will remain the same. The cost of replacing all these streetlights will be recouped within 6 years.
But what about the cost of home floodlights? Assume that, throughout the UK, there are 2.2 million home "security" floodlights that are on, on average, 30 minutes per night (see the Environmental section, above). They will cost a total of £10 million a year for 500 watt lights alone (assuming the electricity used costs 5p per KW/hr).
In addition to such direct costs, light intruding onto neighbouring properties can reduce property values.
Related News items
February, 2005
BBC News: Cathedral lighting in cash crisis:
"Norwich Cathedral may be plunged into darkness at night to save money unless more funds can be found for lighting.
Officials say they are considering turning off the floodlights to save some of the £2,500 a day running costs. "
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