The streets of Europe could soon be lit by "solar trees". These self-contained streetlights will save cities energy and would cut down on the carbon emissions and also slash the bills of local authorities. The tree was designed by Ross Lovegrove, a British designer are not only efficient but also attractive and bring nature into a gray city environment. The branches of the solar tree were decorated with 10 solar lamps, each one comprising 36 solar cells; they also had rechargeable batteries and electronic systems. A sensor was used to measure the amount of light in the atmosphere and trigger the solar lamps to go on automatically at sunset and off at sunrise. The solar trees went on display for four weeks in October on a busy street in Vienna, Austria. The solar trees provided enough light during the night-time even when the sun did not show for as much as four days in a row.

The use of more energy-efficient lighting in the Austrian city of Graz, with a population of almost 300,000 saved the city 524,000 KWh of electricity and US $96,800 in 2005. An Italian company specializing in designer lighting systems, Artemide, as well as the world's largest producer of photovoltaic (PV) cells, the German company Sharp Solar, joined forces to turn the design into reality. Solar cells could soon be used in all areas of everyday life from clothes to satellites - including Christmas trees. Using solar powered LED light systems on trees would cut down on the carbon emissions and also slash the bills of local authorities.