Solar Plant in Okayama Uses LED Lights to Scare Away Crows (2)
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
Cracking occurred again after end of trial use period
The "BB Flash" is installed on corners of mounting systems near the top of arrays (unit for fixing solar panels to mounting systems). The device is equipped with LED lights that emit light toward the sky. The device was originally designed for use for utility poles and developed to prevent crows nesting on them.
In the daytime, various flashing patterns are periodically emitted skywards above the arrays at random to scare away crows (Fig. 4). The "BB Flash" is equipped with a solar battery and does not require a dedicated external power supply. It is compact, light and comparatively easy to install.
The mega solar power plant had an opportunity to lease the devices for free from the manufacturer from May to October 2017, and five of them were installed to check the effect.
After installation of the devices, the number of panels cracked by stones dropping seemed to have slightly decreased, but the preventive effect of the devices was not evident enough to convince themselves to actually purchase the products. Eventually, the devices were removed from the mounting systems and returned to the manufacturer after the free trial use period.
Following this, cracking of solar panels began to occur more frequently again. The operator finally realized the effect of the devices and decided to purchase them. The operator purchased 10 units, twice the number of units leased for trial use. Following installation of the units in June 2018, the number of cracked solar panels dropped to about one per year.
The flashing emitted from the BB Flash is designed to look like hornets to crows. The device was developed by considering the nature of crows, which hate strong and instantaneous lights, and lights that change randomly like hornets.
Crows continue to be alarmed by lights without getting used to them when they are emitted in various timings and strength. The luminance changes depending on the amount of solar radiation. The luminance alters because of the change in the power amount stored in the capacitor due to change in the output of the attached solar battery.
The number of LED lights that emit random lights was increased to four per unit in the third generation of the product, starting from one for the first generation and two for the second generation, realizing effective lights that crows do not easily get used to. The second-generation units were leased for trial use at the mega solar power plant, and the third-generation units were purchased after the trial use.