Flash lights in patterns to keep crows away

What the group had not anticipated during operation was that the cover glass of solar panels was occasionally broken. This seems to be attributed to "stone dropping" by crows (Fig. 6). The damage is about five panels per year at the most.

Fig. 6: Stones apparently dropped or placed in mounting system gap by crows (source: Nikkei BP)

There are not only rice and vegetable fields but also forests and mountains around the mega-solar plant. A number of black kites and crows live there, constantly flying around the mega-solar plant (Fig. 7). When I visited the site for an interview, crows were resting on the arrays as well.

Fig. 7: Black kites and crows found on utility poles around solar plant (source: Nikkei BP)

Crows not only leave their droppings on panels but also sometimes pick up stones and drop them onto solar panels while flying. Many mega-solar plants suffer from cover glass broken by crows in this manner.

Mori Trust immediately replaces any panel as soon as its cover glass is found broken. Many panels continue to generate power as much as before even after the cover glass is broken; however, broken cover glass might remotely cause cells (power generation elements) to get damaged and sparks to be generated. Focusing on such safety reasons, Mori Trust replaces the panels in question as soon as possible.

With a view to preventing damage from stone dropping, Mori Trust added a measure against crows inside the power plant site. The company attached units to the arrays that emit light up in the air that crows dislike (Fig. 8). To verify their effect, the units were set up through about half the site.

Fig. 8: Device that emits light to keep crows away (source: Nikkei BP)

The adopted units are the "Bird Bee Flash" manufactured by Toshin Electric Co Ltd (Yodogawa-ku, Osaka City) (See related article).

These LED lights are set up in high positions on the arrays. During the day, the unit regularly emits light into the air above the arrays in various random patterns that crows dislike. This device was originally developed for mounting on utility poles and preventing crows from nesting there.

This device is embedded with a solar panel and requires no dedicated external power supply. As it is small and light, it can easily be attached in a small space on the corner of a mounting system.

After setting up these devices, the number of solar panels whose cover glass got broken by stone dropping decreased. However, as the number of broken cover glasses has also decreased in the area without these LED devices, it is difficult to determine the effect of these devices.

Facility overview