LED street light bulbs from Osram will soon light up the entire old town of Regensburg, Germany. The city initially equipped two streets with the retrofit light bulbs – developed by Osram Opto Semiconductors and Siemens Regensburg – to test whether this technology would be right for the medieval world heritage site. After residents and passersby approved of the new lighting in surveys, all 250 light bulbs will now be switched over to LEDs by 2011. As the magazine “Pictures of the Future” reports, this new solution will cut power consumption in half. It will also reduce maintenance costs, because LEDs last more than twice as long as conventional street light bulbs. The new bulbs generate a warm light, similar to daylight, that shines on the historic building facades, highlighting their natural colors even at night.
German street lights consume three to four billion kilowatt hours annually. This is an issue for many communities because about one third of street lighting systems are 20 years old or older. By modernizing them, cities can reduce their electricity costs by about 50 percent. In addition, there is the EU directive that has effectively ordered the demise of the conventional light bulb, which will impact the less efficient street lighting methods. LEDs offer an attractive alternative because they are not only highly efficient, but they can be individually actuated and adjusted. Their light rays can be directed precisely to the desired areas and thus enable less light usage overall.
The Regensburg LED light bulbs comprise a maximum of 54 high-performance LEDs that can be easily screwed into the old sockets. In the narrow streets and alleys, only a few diodes will be directed downwards while most of the long light beams will be aimed to the side. This means that the dark zones between lights that are typical in alleys will no longer exist. The bulbs will generate hardly any light upwards or into the windows of the residents – instead, they will be directed specifically at the beautiful building facades. Thanks to its high color reproduction index, LED lighting will allow the passersby to easily see contrasts and colors and also recognize oncoming people from a greater distance.
Federal stimulus packages are helping cities and communities switch over to energy-efficient street lighting. The Siemens subsidiary Osram is also working with communities, utility companies, and finance partners like Siemens Financial Services on so-called contracting models, which allow the investment installments to be offset by savings.