Insect-friendly lighting Selux

More than light
Insect-friendly lighting

On 1st March 2022, a new amendment of the German Federal Conservation Act came into force. Based on this, in paragraph 41a, wild animals and plants are to be protected from avoidable light emissions. In collaboration with the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) and the Departement of Lighting Technology TU Berlin, Selux has developed a road light that is designed to help to protect the habitat of insects in particular and yet still guarantee sufficient light for the safety of human beings.

Night-time lighting has many positive aspects: it helps with guidance; it increases the feeling of security on roads and paths. Light not only makes urban settings more attractive but also contributes considerably to the quality of life for residents. At the same time, in many places, light is cast not only onto roads and footpaths but also into the night sky. Exterior lighting significantly impairs the lives of nocturnal animals. Flying insects are attracted in droves by what is known as the "vacuum cleaner effect" of light sources, birds are distracted from their migratory routes and the habitat of bats is severely constricted. All this has negative consequences for our entire ecosystems.

As part of the German government’s Programme for Biodiversity, a transfer project for protection of species through environmentally friendly lighting started in 2019. The IGB developed, in cooperation with researchers from the Departement of Lighting Technology TU Berlin, a new road lighting design that is intended to minimise the reflection of light onto the flight paths of insects.

The special insect-friendly lighting design is developed so that the light emission from road lighting is no longer visible at the luminaire heads but only on the pavements and roads. At the same time, lighting standards for road safety are certainly complied with.

The brightness of the newly developed street light is examined at the Black Lab of the TU Berlin.

Dr. Sibylle Schroer, Project Coordinator of the Berlin Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin visiting our production site at Zachow in Brandenburg together with Olaf Rieling, D/A/CH Sales Manager.

How does a street light that takes into consideration the needs of nocturnal animals work in practice? A light that casts no light onto the flight paths of insects? In a German wide tender process, Selux was awarded the contract to manufacture a road light that meets these criteria.

What are known as Dark-Sky technologies have been a research focus for many years now and at the same time are a focus theme of Selux. It was possible to incorporate previous findings into the present project that is connected in particular to the lighting of cycle paths and public spaces in parks. In these application situations, a sharp demarcation of light known as a cutoff is desirable. Not only are the illuminants less visible to insects but light should also not collide with the pole to prevent it being reflected. Furthermore, the light would have to be controllable and dimmable.

The Tal pole-top luminaire was selected as the basis for this transfer project, equipped by the Selux engineers with the latest lighting technology. The custom-designed optics and a light-shade system now guides the light directly down and protects passers-by from glare. At the same time, it prevents unnecessary light scatter above the horizon level and hence lighting pollution of the night sky.

By comparison: With conventional street lighting for example former column luminaires,, the light is beamed directly at the flying height of insects. The unshielded light spots can cast light into the insect paths and form barriers within the habitat of insects. With the new, insect-friendly lighting technology, this "vacuum cleaner effect" is minimised as much as possible.

Insect-friendly road light design will initially be tested by the IGB on a test area consisting of 24 luminaires. The first, particularly insect-friendly Tal luminaires were installed in February 2022 on an experimental area in Havelland in Brandenburg. The scientists will be examining the attractiveness of the street lights to insects and their behaviour one season before and after the conversion. Afterwards the luminaires will be installed in partner municipalities, in Krakow am See in Mecklenburg, in two communities in Brandenburg and in Fulda. The behaviour of insects with respect to the luminaires will be examined here for two years before and after they have been installed and in a direct comparison.

If this evaluation is positive, the light intensity distribution curves and the luminaire design are to be made available as a part of recommendations for municipalities, authorities and companies. The specific solution proposals are developed to protect public and private areas from unwanted light emissions as well as the the natural habitat of insects.

In just a few small steps, light emissions can be reduced, thereby protecting nocturnal animals active by night.

Blue and white light will attract most insects. A more friendly alternative is warm light with aless blue content of the light spectrum. In the habitats of sensitive and endangered animals, lights with a max. light temperature of 2700 K should be used or the extremely warm light shade “PC Amber”.

Light should not be brighter than necessary. Make sure that the norms are not over-interpreted but used as a recommendation for an upper level. Some surfaces reflect more light into the night sky when illuminated than others analyse the reflecting potential and dimm the illuminance accordingly. We recommend checking whether your lights unintentionally also illuminate the poles or other objects.

Today, existing light poles can simply be equipped with motion sensors or time controllers. These sensors ensure light is available at the right times and, whenever it is not needed, can be dimmed or switched off completely.

Unnecessary light scatter can be avoided using special optics. This means that no direct light is emitted into the horizon or in shallow angles. Precise downward light therefore enables even more precise accentuation.

With LED technology, nowadays new materials and manufacturing processes provide significantly more possibilities for checking light distribution, alignment, intensity and the colour spectrum of luminaires. Selux is currently developing a variable optic for road lights, which can provide light for various road geometries – whether this be a cycle path or road.

On the ZDF documentation series plan b, the author Felix Franz accompanies researcher Dr. Sibylle Schroer on her mission to obtain insect-friendly lighting on our roads.

Broadcast date: to be announced