Illuminated litter bin

Junk light

 

Junk light is the result of inefficient applications and excessive use. It is light that serves no purpose in terms of illumination. This junk cannot be recycled; it can only be prevented.

 

As a result of progress in lighting engineering and the availability of cheap energy, light became a cheap commodity in the course of the last century. Economically, there was less and less reason to give thought to the careful use of light (Posch in Posch, Freyhoff & Uhlmann, 2010).

 

 

Shanghai at night

The light race

 

The human eye can adjust from the dark to bright light relatively quickly. But in the case of dark adaptation, i.e. the transition from bright light to darkness, it takes much longer for optimum vision to be restored.

 

In the context of public lighting, this explains the tendency to illuminate dark areas more brightly, thus triggering a kind of “light race” (Hänel in Posch, Freyhoff & Uhlmann, 2010).

 

There is a danger that more and more light will be produced outdoors with the help of increasingly efficient light sources (Rebound-Effect).

 

 

Europe at night

Facts and figures

 

Lighting accounts for 19 percent of electricity consumption worldwide and 16 percent in the European Union. Eighty percent of the total is industrial and office lighting, retail lighting and street lighting etc, with private households accounting for the remaining 20 percent

(http://www.strassenlicht.de/..., August 2011).

 

Public lighting in Vienna:

150,000 light fittings, 227,000 lamps, 2,850 km illuminated streets and paths, 14,000 kW connected load, 56 million kWh annual consumption

(http://www.wien.gv.at/verkehr/licht/..., August 2011).

 

 

Potential energy savings

 

In Austria, lighting accounts for 10 to 15 percent of total electricity consumption.

 

The optimised lighting systems installed in many places mean less consumption, lower costs and reduced carbon emissions.

 

In Austria, efficient street lighting could generate savings of 300 million kilowatt hours of electricity per year or 45 million euros (0.15 euros/kWh) or 58.500 tons of CO2 (http://www.gemeindebund.at/..., June 2011; http//www.e-control.at/..., August 2011).

 

 

Carbon dioxide

 

Electricity generation, especially through the combustion of non-renewable sources of energy, involves carbon dioxide emissions. Excessive carbon dioxide in the atmosphere contributes to the greenhouse effect, which in turn accelerates the process of global warming.

 

Lighting alone is indirectly responsible for the production of thousands of tons of carbon dioxide a year. Efficient lighting saves energy, and the savings in kilowatt hours translate directly into reductions in carbon dioxide emissions.

 

Efficient lighting makes a valuable contribution to climate change mitigation!