12 Sheep Pastured at 1.8MW Solar Plant
Ubuyamamura, Aso-gun, is situated almost in the center of Kyushu and at the northeast end of Kumamoto Prefecture. The village is surrounded by Kyushu’s major mountains such as Mt. Aso, Mt. Sobo and the Kuju volcanoes. It adjoins Minami-Ogunimachi, Aso-gun, to the northwest, Aso City to the west and the south, and Taketa City, Oita Prefecture, to the east and the south.
Ubuyamamura is a mountain village consisting of undulating plateaus, where Mt. Aso’s caldera and the base of Mr. Kuju meet, with steep slopes formed by the eroding plateau at an altitude between about 500 and 1,047m.
The “Ubuyama Yamaga Solar Energy Farm,” a mega- (large-scale) solar power plant with an output of about 1.8MW, is located in Ubuyamamura
The amount of annual power generation is expected to amount to about 1,943,812kWh, which is equivalent to the power consumption of about 540 general households. The generated power is sold to Kyushu Electric Power Co Inc at 40 yen/kWh (excluding tax).
Tokyo Energy & Systems Inc provided engineering, procurement and construction (EPC) services, adopting panels of Canadian Solar Inc and PV inverters of Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC).
JAG Energy manages the facility while JAG Power Engineering Co Ltd (Chiyoda-ku, Tokyo), also part of the Japan Asia Group, operates and maintains the power plant.
There are many forests, pastures and related tourist facilities around the mega-solar plant at Ubuyamamura in the plateau region.
Although the site of the mega-solar plant was private idle land, it had originally been designated as an agricultural promotion area. Agricultural promotion areas are those required to promote agriculture under the local government’s agricultural promotion areas establishment plan.
When developing the solar power plant, the site was omitted from the agricultural promotion area with the category of land use converted from agricultural land, thanks to the efforts of many parties including the landowner and cooperative enterprises. The rented piece of land is approximately 37,000m2.
The Japan Asia Group endeavors to develop solar power plants that are suited to the properties of the location and contribute to local development through solar power generation.
The group decided to pasture sheep at the mega-solar plant in Ubuyamamura, making the best use of the area that has many pastures.
The plant can expect the sheep to graze on the weeds in the site and help alleviate the load of manual weeding.
JAG Power Engineering, which operates and maintains the plant, entrusts weeding to a local company, and the sheep are being leveraged as part of the business. This local company is engaged in agriculture-related and weeding businesses and manages the sheep as part of its weeding work.
Some mega-solar power plants in Japan have adopted sheep and goats. However, in most cases, the adopted livestock are only a few in number.
Ten sheep were initially pastured at the mega-solar plat in Ubuyamamura (Fig. 2). The local company entrusted with weeding purchased and managed the sheep, which stay at the Ubuyama Yamaga Solar Energy Farm throughout the year. This number of sheep make the site appear like a real pasture.
The plant initially adopted 10 sheep, but the number has increased to 12 as two lambs were born (Fig. 3).
The lambs were born in the early spring of 2016. As nearly six months has passed, you can see them graze in the power plant with their parents.
Although sheep are said to be nervous, these ones fearlessly come close to people, partly because they are taken care of by the human managers every day.
The panels were set relatively low at about 60cm from the ground. Nevertheless, there have reportedly been no traces of the sheep climbing up on the panels, partly because they do not have a habit of climbing up to high places like goats.
Pasture grass was planted inside the mega-solar site. It was first planted with the view to making sheep graze on it with other weeds, but it also turned out it prevented weeds from growing in the course of plant operation. JAG Power Engineering believes this could be attributed to, for example, the fact that pasture grass has roots stronger than other weeds.
Inside the plant, there are some weeds that the sheep wouldn’t eat. Such weeds include bracken.
Sheep also eat bracken’s soft sprouts, which humans like. However, as the stalks grow harder and the ferny leaves spread, sheep stop eating them. When such weeds grow more than a certain height, the local company eliminates them using human resources.
The local company that manages the sheep goes to the mega-solar site every day. In the morning and the evening, responsible staff replace the water for the sheep and clean up any mess (Fig. 5).
When the sheep get thirsty, they return to the shed and drink water from a vessel set under a tap.
Both pasture grass and weeds are abundant in summer. However, they both die in winter. For that reason, in winter, the plant purchases pasture grass and feeds it with other food to the sheep in the shed.
The sheep sometimes stay in the shed to avoid the heat in summer and the cold in winter.