Oslo has reduced energy consumption by 70% and CO2 emissions by 1440 tonnes per year by introducing an innovative and energy-efficient form of street lighting. 10,000 high-pressure sodium lights using an “intelligent lighting” system that adjusts light according to need have been introduced around the city.
What is it?
The initiative is a joint-venture between the City of Oslo and Hafslund ASA, the largest electricity distribution company in Norway. Hafslund are responsible for the running and maintenance of 250,000 street lighting points in the greater Oslo area.
Old fixtures containing PCB and mercury have been replaced with high-performance high-pressure sodium lights and an advanced data communication system using powerline transmission has reduced the need for maintenance. This reduces the level of light when needs are low, saving energy and cutting pollution.
How does it work?
Lighting represents 15-20% of the Norwegian annual electricity demand of 125 TWh and 3% of this goes to street lighting. The new lights include electronic gears in each lamp that measure rates of consumption by the different consumers – including private companies, public parks and streets.
This means energy consumption can be accurately measured and taxed. Users are not billed on anticipated volume of use (older systems are often based on fixed operating hours) but their actual consumption, creating incentives and consumer demand for greater efficiencies.
Advanced communications mean each lamp can be dimmed individually when traffic and climate conditions permit. This increases the life expectancy of lamps and equipment, generating huge economic and energy savings. Moreover, the powerline transmission of data to a GIS-database containing information on every single fixture enables the operator to easily identify lamps that have or soon will burn out. This technology is estimated to increase efficiencies by 30%.
In Oslo, 10,000 intelligent streetlights are operated by a central database that monitors and administers commands. The system utilizes telecommunication (GPRS technology) between the central database and the switch cabinet located in the street. The switch cabinet receives messages from the central database and transmits these to the individual lamps via the existing 230V power cables.
After 2-3 years of implementation time, the system is now fully equipped with all its components. Some minor problems have occurred, mainly related to production failure in some communication units, but on the whole, the system has performed well under normal operating conditions. There has been no increase in the level of public complaints, meaning the system is functioning at least as well as the old system.
The predicted energy savings have been achieved, whilst the cost reductions expected due to a reduction in overall maintenance have not yet been fully obtained – this is due to the small scale of the project at present. Scale-up to the city’s 250,000 lights could increase the impacts in energy saving and emissions reduced by 25 times and deliver the scale economy needed to make significant financial savings.
CO2 emissions reduction
Electricity supply in Norway is 98% hydropower generated. Norway only import fossil-fuel based electricity in 5 out of 10 years and are normally an electricity exporter.
Lighting in Oslo is 100% provided by hydropower sources, yet if oil had been used to generate the required power, the city would have emitted 1440 tonnes CO2 per year for these 10,000 lights. In real terms, the high efficiency of the lights means 70% of the electricity used under the old system for street lighting is now diverted for use elsewhere, potentially reducing emissions further.
CO2 calculation made by city for 10,000 luminaries used to date. Norway uses 98% hydropower for electricity supply, so the calculation is based on hypothetical burning of oil for electricity supply.
The energy saving potential has been estimated to 4.5 GWh/year. There are plans for continuously replacement of old inefficient streetlights. Today 15 % of the streetlights in Oslo are renovated and over the next 5 years, this figure will dramatically increase.
For the 10,000 units, the breakdown of investments are as follows:
- €6 million for retrofit of old luminaries
- €3 million for new intelligent technology
- €3 million for installation
- €12 million in total
The implementation of an overall database structure independent of manufacturers delivering the light installation is in an implementation phase together with other European partners from the EU supported E-street project. The E-street project covers energy efficiency activities, development of international standards and clustering of street light owners. The project counts 12 partners from 11 European countries.