The Economic Cost of light pollution
An energy efficient light (such as the one on the left) costs just £3 per year to run, and does a better job of lighting your property (because it does not cause glare) than a 'security' floodlight which cost £60 per year to run (assuming the light is on 3 hours per night). Oh, and the bulbs last longer, too!
For more details, see our Cost Calculator.
The cost of electricity that is wasted, by sending vast amounts of light up into the sky
| 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).|
| 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.|
| 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.|
| 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.|
Consider UK street-lights...
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).
Economics is why...
- From 2002-2005, the City of Calgary (Canada) replaced all their streetlighting with efficient lights - saving the city at least $2 million a year (the money saved will have increased significantly in the last few years, as energy costs have similarly increased). The new light fittings ensure that 100% of the light produced shines onto the streets without wastage, so the night-time brightness of the streets remain the same, even though the power of each street light has decreased. The cost of replacing all these streetlights will be recouped within 6 years.
- The City of Oslo, Norway, installed intelligent street-lighting [doc], leading to energy savings of 60-70%.
If water were leaking from a tap, it would be repaired promptly to avoid wasting money. Unfortunately the same cannot be said for a leaking light. Two power stations' are required every night to make the smog of light pollution that hangs over our cities at night.
In Britain alone, over £120 million worth of electricity is wasted per year from inefficient street-lights (see above). A third of the light from an average street-light never actually hits the street - £120 million a year worth of electricity 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).
In Leicester (a typical UK city with a population of about 300,000) about 5 million kilowatt hours per year is going directly to light up the night sky. This means that 5 million kg of CO2 is needlessly pumped into the atmosphere per year. That's about 14 tonnes per day for Leicester alone (a so-called "Enviromental city"). This is equivalent into the energy generated by a couple of wind turbines for Leicester alone. If Leicester is typical of the UK, this adds up to about 450 wasted wind turbines UK wide.