Aiming to reduce the ecological footprint of street lighting, product design student Tobias Trüenabacher has conceived PAPILIO, a wind-powered street lamp that only lights up when needed.
When first developing the idea, Trübenbacher looked at the growing potential for utilizing wind power, particularly in city streets, as well as the negative impact of intensified artificial light in densely populated areas. “Light pollution not only has bad health effects on humans, like causing sleep disorders, depression, cardiovascular diseases, diabetes and cancer, but has also a serious impact on flora and fauna,” explains Tobias. “Extinction of species, orientation loss of migratory birds, significant disorder for fish migration, as well as disturbed biorhythms of plants like for instance delayed leaf shedding, are only a fraction of these consequences. It is estimated that currently in Germany alone around 1.2 billion insects die because of street lighting in one single summer night.”
The lamp PAPILIO is reducing the ecological footprint of street lighting many times over by generating electricity with an integrated wind generator while at the same time minimizing light pollution. An integrated Savonius rotor, made of folded sheet metal and connected to a 300 Watt generator, is used to produce climate-neutral energy. For its operation the wind direction is irrelevant and due to its diagonal orientation, the rotor works with vertical (natural wind) as well as horizontal air streams (e.g. airflow caused by traffic).
A rechargeable battery stores the generated electricity and can thus also bridge periods of calm. This makes it possible to either operate PAPILIO completely autonomously without a necessity for expensive underground electricity infrastructure, which offers benefits and new opportunities particularly for remote regions. Alternatively, the product can also be connected to an existing power grid in order to feed surplus energy into the network during strong winds.
In order to minimize light pollution, the product is designed as a “full-cut-off light”, only emitting light downwards with a bam angle far below the horizontal. To reduce the harmful impacts of artificial light even more, the street lamp provides an infrared sensor, only activating the light when it is actually needed. In addition, the used light spectrum is less attractive to insects due to a lower blue component and a warm color temperature of 2800 Kelvin.
Besides the option to mount the lamp on a regular mast, there is also the possibility to attach it to a house wall or any suitable architectural element. Therefore, there are two possible mounting options: pointing downwards to create a vertical light cone illuminating the area directly below the luminaire, or the other way around to generate an obliquely incident light with a larger-area illumination.
Lantern masts provide an ideal prerequisite for generating wind energy, since both their stable anchoring in the ground and their height are ideal for attaching small wind turbines, as close-to-the-ground winds are strongest at a height of 3 to 6 meters. Moreover, besides natural wind, street lamps are usually surrounded by numerous other, unexploited, anthropogenic energy flows, like the displaced air from passing cars, buses or trains.
Against this background, the PAPILIO street lamp functions as a “prosumer” for climate-neutral cities of the future: it is not only a “consumer” (as is the case today with streetlighning consuming nearly a fifth of the global electricity), but operates at the same time as a “producer”, generating the energy it consumes or even beyond that, feeding surplus energy into energy networks.
With PAPILIO, the process of generating energy becomes the central element of the street lamp and an aesthetic play, enriching streets, walkways and city squares — both during the day and at night. It is a street lamp for a future worth living in.
Lanterns determine the character of streets and squares. The implementation of PAPILIO into a city district can become a publicly effective sustainability statement and thus motivate residents in their everyday life to take a part in actively fighting for climate justice and a transformation of our cities into climate-neutral, future-proof environments.