Intelligent LEDs replace traditional streetlights

LED street lighting is gaining popularity. Around the world, more and more cities are switching over or getting ready to do so. The systems they have chosen are not only LED-based but also intelligent. The aim of this is to improve both the traffic safety in the area and the general well-being of the population while at the same time cutting power consumption.

Because street lighting consumes a lot of energy, it takes an increasingly large bite out of the available budget. Moreover, all this energy consumption is a burden on the environment. Worldwide, street lighting accounts for around six percent of greenhouse gas emissions. So it’s no wonder that many cities want to make their lighting smarter and more efficient.

Smart solution, far-reaching benefits

LEDs are a more efficient form of street lighting because they convert electricity directly into light particles, in contrast to sodium lamps, in which light is a by-product of the conversion of electricity to heat. LEDs also have no warm-up time and their colour and intensity can be easily adapted to the surroundings.

As a result, the widespread use of LEDs would benefit not only the environment and the pubic purse but also the well-being of the population. Certain combinations of light spectra and intensities can, for example, improve alertness, and eye exposure to an accurately adjusted dose of blue light reduces fatigue during the day. Not only can light be tailored to the surroundings, it can also be used in a smarter way. For example, by integrating motion sensors, the lighting dims to 10 or 20 percent if there is no movement in the street. In this way, even more energy is saved. Finally, it is possible to go a step further and leave the lighting, from installation and maintenance to repair and recycling, entirely to a service provider.

At the moment, a switchover to smart LEDs is being planned for Copenhagen in Denmark and the New Zealand capital Wellington. In addition, various places in Europe are running pilot projects. Several cities have already implemented a complete or partial switchover. The largest project so far is in Los Angeles, which switched to a complete system of LED lamps controlled by a remote management system. Barcelona, in Spain, uses lamps that detect motion and weather conditions. 

Los Angeles before and after

New Zealand

The New Zealand capital Wellington is planning in the near future to be the first city in the southern hemisphere with an intelligent LED-based street lighting system. The city plans to replace all the street lighting outside the business district - a total of 18,000 units. These LED bulbs can be automatically dimmed when no one is nearby. The street lighting in the business district usually stays on throughout the night and will therefore not be replaced immediately.

Danish Pilot Park

In Copenhagen, capital of Denmark, a large-scale pilot project for intelligent LED street lighting has been started in a fully-fledged test park. The city plans to balance its carbon emissions by 2025 and this experimental park is one of the ways it hopes to do this. The Danish Outdoor Lighting Laboratory (DOLL) is a test area in the suburb of Albert Lund, where many intelligent outdoor lamps and systems are being tested. The public are invited to participate and foreign manufacturers and governments are encouraged to participate. In so doing, the project can encourage more cities to switch over to other types of lighting.

The street lighting systems of 25 different companies have been installed over a distance of 9.2 km and an area of 1.5 km². Each lamp has a separate IP address so that they can be controlled remotely. This lets the city test smart lights that dim when it is sunny, shine brightly when people pass by at night or automatically send an alert when a fault occurs. The Dutch company Tvilight will test streetlights that adjust their brightness in response to movement in the vicinity. The DTU (Technical University of Denmark) will try-out CopenHybrid - a mast that powers street lighting from a combination of wind and solar energy. Sensors that monitor traffic density, air quality, noise, weather conditions and UV radiation are installed throughout the site to assess the type of environment the lamps are operating in. With this information, it will be possible to decide which lights offer the greatest advantages in terms of costs and emissions.

European initiatives

The European government has also studied the effects of SSL (Solid State Lighting) in various projects, and aims to promote its use for both indoor and outdoor applications via

Data from a European project with test sites in Bordeaux, the campus of Riga Technical University (Latvia) and the University of Aveiro (Portugal) show that intelligent SSL systems can deliver energy savings of 65 to 73 percent. Because the light they produce is also brighter and whiter than that of the yellow sodium lamps, there are visibility and colour contrast benefits for road users.

That SSL systems can also be used to improve the visibility of public buildings and spaces was shown by a test set-up at Belfast City Hall in Northern Ireland for the ILLUMINATE project, in which the colours and configurations of the lighting were adjusted to suit special occasions while still achieving an energy saving of 67 percent.

Finally, it is clear that although smart LED lighting systems are more expensive to buy and install than classic sodium lighting, lower energy consumption and the lifetime of the LEDs (10-15 years compared to 3-5 years for sodium) result in a short payback period of 2- 3 years.

One of the topics covered by the workshop ‘How to truly eco-innovate in the lighting industry?’ on 11 February will be eco-innovation using LED-based street lighting.