1st Project Finance for Agricultural Mega Solar Plant Revitalizes Idle Farmland (2)

2017/11/30 20:43
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Institute

Continued from 1st Project Finance for Agricultural Mega Solar Plant Revitalizes Idle Farmland (1)

Solar sharing is a rising star

Shimin Energy Chiba started the operation of an agricultural solar power plant for the first time in September 2014. About 500 panels manufactured by Amerisolar (70W/sheet) were installed at the plant. Five PV inverters manufactured by Omron Corp (5.9kW) were introduced to the plant. The power is sold at a unit price of 36 yen. The construction cost of about 8.2 million yen was raised from supporters from the public; the plant is a "public joint investment type" (Fig. 8).

Fig. 8 : The agricultural solar power plant, connected to a low-voltage power line, was constructed in 2014 raising funds from the public. (source: Nikkei BP)

Tsubaki, who is engaged in agriculture in Sosa City, has been involved in the solar sharing project since the first solar sharing facility. The Kaihata District, as the name indicates, was developed into fields by forest reclamation. The clayey soil of the district is weak and has poor drainage. High-value-added crops such as vegetables cannot be grown in the district and so it is difficult making a living from farming.

"Many fields are abandoned because of this reason," Tsubaki said. "We sought to construct outdoor solar power plants, but we had to give up because it was impossible to convert the farmland for the reason that the fields were created using public funds and are in the agriculture promotion area."

Under such situation, he met Higashi, who was promoting solar sharing, and they worked together to realize construction of solar sharing power plants in the Kaihata District.

"Solar sharing is a rising star in the Kaihata District, where agriculture was about to reach a dead end," Tsubaki said.

Higashi pointed out the issues of conventional-type solar sharing projects saying, "The owner of the farmland, the power producer and the farmer are different, and many farmers are conservative and skeptical about solar sharing. Given that the number of farmers is decreasing, it is difficult to find ones who grow crops under solar panels even if a solar sharing facility is constructed."

Shimin Energy Chiba aims for the installation of solar panels by a farmer on his/her own farmland and cultivation of the land under the panels by the farmer. The solar sharing project in Sosa City is close to the image of the ideal situation, Higashi said.

Young local people established an agricultural production corporation

The farming at the Sosa Mega Solar Sharing No. 1 Power Plant is entrusted to the agricultural production corporation Three Little Birds of Sosa City. The corporation was jointly established in February 2016 by local organic farmers, new farmers and Chiba Ecological Energy. Tsubaki is actually an executive of the corporation, while also being a power producer and a farmer.

In Three Little Birds, young people in their 30s are engaged in organic farming and natural farming. Tsubaki expressed his expectations saying, "A stable income is ensured because of the farming entrusted by the solar sharing project, and young people can now undertake new farming methods including pesticide-free farming and organic farming."

Shimin Energy Chiba has already started the operation of two solar power plants of less than 50kW output, which are connected to low-voltage power lines, in the Kaihata District. It also obtained certifications for about 40 sites for low-voltage projects and two sites for middle-scale solar power plants of about 900kW output. If all the facilities are completed, the total output will exceed 4MW, including the mega solar power plants that are already in operation.

EGpower of Shinjuku-ku, Tokyo, which constructs and operates solar power plants in Nagano Prefecture and is engaged in the retailing of electricity with a focus on renewable energies, also constructed solar sharing plants on two sites for connection to low-voltage power lines in the Kaihata District of Sosa City this spring, in collaboration with Shimin Energy Chiba (Fig. 9).

Fig. 9: EGpower is the power producer of this site connected to a low-voltage power line. (source: Nikkei BP)

"Solar sharing increases the income of farmers whose income from farming alone is insufficient and helps revive abandoned farmland," said Hideaki Takemura, president of EGpower. "The significance has yet to be realized in all regions throughout Japan. We would like to expand the successful cases in Sosa City to other regions."

Power generation capacity increased 15% by incorporating single-shaft tracking-type mounting systems

Shimin Energy Chiba has also been developing technologies related to solar sharing. The company incorporates foundations and mounting systems designed for solar sharing by Akira Nagashima, who was formerly a designer and developer at a major agricultural machine manufacturer and currently represents CHO Technical Research Institute.

The mounting systems that are 2.5 to 3.5m in height are built by assembling single pipes in structures similar to wisteria trellises. Narrow solar panels of about 24 cells (power generation elements) are arranged on the mounting systems. The shading rate becomes approximately 30% if the distance between the strip-shaped panels is set at two times the panel width. Nagashima developed this system in 2004 and applied for a patent.

However, joints in the mounting systems built with single pipes are fixed by joint brackets, and the issue of strength and durability had to be solved. As a solution, four single pipes were fixed diagonally as a brace to all joints between supporting pillars and beams to enhance the strength.

Shimin Energy Chiba developed and commercialized its original couplers for use as braces to enhance the strength and workability (Fig. 10).

Fig. 10: Special couplers were developed for use as braces for single pipes. (Source: Nikkei BP)

"If the structure is configured so that farmers can assemble and repair it by themselves, the installation cost will be reduced significantly and business feasibility will improve," Azuma said. "If farmers operate solar sharing plants on their own farmland, feasibility will be ensured even if the tariff drops below 20 yen/kWh."

Nagashima, who created the prototype of the wisteria trellis-type solar sharing equipment, developed a single-shaft moving-type (tracking-type) mounting system in 2014 in collaboration with Shimin Energy Chiba and other entities. Panels on the conventional wisteria trellis-type mounting systems are installed facing south because the panels are fixed to them. However, panels on the moving-type mounting systems are installed facing east or west because the panels move from east to west in line with the movement of the sun.

The moving-type mounting systems are already incorporated in the agricultural power plant operated by EGpower, and are connected to low-voltage power lines (Fig. 11). The panels move automatically from the east to directly above (horizontal) and then to the west, tracking the sun, between 9:00 in the morning and sunset. The panels are horizontally positioned on days with strong wind due to typhoons, etc, and on cloudy days. Based on the results up to now, the moving-type mounting systems improve the power generation capacity by about 15%.

Fig. 11: Panels are fixed facing east or west on the newly developed moving-type (tracking-type) mounting systems. (source: Nikkei BP)

New challenges, in terms of organization and technology, have arisen for effective sharing of the sun by crops and panels. The district, where the amount of abandoned farmland was increasing due to poor soil fertility, becoming a burden to the region, has become the mecca of solar sharing and is developing into an advanced area highlighting new farming methods.