Energy-efficient refurbishment of historical streetlights in the city of Düsseldorf
The city of Düsseldorf renovated or replaced the existing gas lights on several streets. The use of more energy-efficient electric light sources together with a demand-oriented power reduction decreased the annual energy consumption and consequently the CO2 emissions.
Summary
The city of Düsseldorf participated with 6 sub-projects in the German national competition "Energy-efficient city lighting". In order to increase the acceptance of the population for the refurbishment and replacement of the historical gas luminaires, the city developed various individually adapted technical solutions.
Technical solutions
Sub-project 1:
In the residential area "Lohausen" the gas lamps were replaced by LED lights. These are individually controlled and dimmed to 30 % of the maximum output.
Subproject 2:
On a main street (Danziger Straße) the existing lighting system from 1960 was completely renewed due to its age. A street lamp with a high-pressure sodium vapour lamp was installed in the new system. The new system is controlled according to traffic. The already available detectors of the traffic management system are used to record the traffic volume. The use of existing traffic data for lighting control has pilot character nationwide.
Subprojects 3 and 4:
The existing gas lighting was replaced by high-pressure sodium vapour lamps on various roads distributed in the urban area. At certain times the systems are operated with reduced output.
Sub-project 5:
The decorative luminaires on Königsallee were previously fitted with free-radiating high-pressure mercury vapour lamps. This resulted in high glare and high light emission. By using a refractor, restoring the existing luminaire reflector and installing a metal halide lamp with electronic ballasts (ECG), the lighting technology of the existing luminaire was significantly improved and power consumption was reduced by 53%. The metal halide lamp meets the requirement of ensuring good colour reproduction at this location.
Subproject 6:
On Düsseldorfer Burgallee, the city replaced the previously used electrically operated high-pressure mercury vapour lamps in the historic gas luminaires. The fixtures of the former gas lighting were reproduced and dummies with integrated LEDs were used instead of the typical gas mantles. The light colour of the LEDs is similar to that of gas lighting. A control system halves the luminaire output depending on time.
Results
Due to the new electrical lighting systems with energy-efficient light sources and a demand-oriented power reduction, the annual energy consumption in the investigated streets was reduced by about 20%. This energy saving reduced CO2 emissions by 428 tonnes.
Further significant advantages for the environment were:
- Light emissions into the night sky are reduced
- LED light reduces the nocturnal insect flying around the lighting by up to 80% compared to other electrical systems
- Extended maintenance cycle and lower repair costs
- Avoidance of low-level radioactive hazardous waste, as gas mantles are no longer used
Conclusions
The high savings potentials here result from the replacement of gas lights. But also in the refurbishment of electric lighting fixtures potential for savings of over 50 % can be achieved, for example when replacing a fixture with high-pressure mercury vapour lamps.
Promotion
Promoting Institutions
Federal Environment Agency (UBA)
KfW Bankengruppe(KfW banking group)
Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU)
Promotional Program
* only available in german *
Source: Environmental library of the Federal Environment Agency (UBA)
