Suburban Solar Plant Shows Consideration for Locals

'Eco farm' run using part of revenues from power selling business

2014/02/18 17:55
Kenji Kaneko, Nikkei BP CleanTech Institute

Higashimatsuyama City, which is located in the middle of Saitama Prefecture, is known for its numerous parks and their rich nature. Given its location, less than one hour by train from Ikebukuro Station on the Tobu Tojo Line, it is also a commuter town with a population of about 90,000.

"Higashimatsuyama Kagayaki Power Plant" is a 2MW-capacity mega (large-scale) solar power plant adjoining a residential area that is a 30-minute walk from Higashimatsuyama Station, the city's central part. Since operations started in August 2013, the plant has smoothly continued to generate more power than expected (Fig. 1).

The power plant is adjacent to a municipal hospital, a welfare institution and an elementary school, with a large-scale residential area on the opposite side of a river. The municipal road running along the site is used as a walking route by local residents. In the morning and afternoon, you can see school children walking to and from school in front of the power plant.

"It is unusual that a 2MW mega-solar power plant started operation at a place one-hour from central Tokyo," said President Takuya Ogushi of Smart Energy Co Ltd (Chiyoda-ku, Tokyo). "We are hoping to contribute to the local community as an urban mega-solar power plant that neighbors a housing area."

Smart Energy also financed Higashimatsuyama Kagayaki Power Plant (Higashimatsuyama City, Saitama Prefecture), a special purpose company (SPC) that is engaged in the planning, development and construction of the power plant and serves as the business operator.

Project revenues partly used for regional contribution activities

In late January, I visited the power plant to collect information. On that day, dozens of other people were also making field trips to the plant by bus from Saitama Prefecture. Inside the power plant, which is in a fenced enclosure, there were two second-hand containers near the entrance. And a board was seen on one of the containers. On the board was written with a writing brush "Taiyo no Sato Higashimatsuyama Kagayaki Power Plant" (Fig. 2). This was a work by the calligraphy club at Saitama Prefectural Matsuyama Girls High School.

Housed inside the containers were PV inverters produced by Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC). In the power plant, 7,994 solar panels manufactured by Sharp Corp were set up. The installation angle was as small as 10° (Fig. 3).

"Considering the plant site is adjoining houses, we decided on the installation angle giving priority to making sure the solar panels did not reflect light onto the windows of the neighboring houses," said Electric and PV Facility Manager Hideharu Kihara of Smart Energy Service, Smart Energy's group company engaged in the plant's construction, management and operation.

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The power plant's name board and panel installation angle are representative of its consideration for the local community. Another feature of this power plant's regional contribution measures is the adjacent site that it manages as an "eco-farm" to grow plants. As you walk along the visitor's route looking at the solar panels, you will come to an empty lot without panels. There is a notice saying "blueberry trees planted.” The saplings, about knee-height, are planted evenly at intervals of about 1m (Fig. 4).

"The blueberries are likely to root well," Kihara said, expressing relief.

He said many of the herbs, raspberries and other plants that have been planted since the power plant started operation did not root and withered.

"Should the blueberry trees grow and produce a lot of berries, we hope the local residents will be able to enjoy them," Kihara said. And Ogushi said, "From now, we’re hoping to plan various regional contribution activities other than planting blueberry trees."

The plant will allot some of its business revenues to the planning costs for the eco-farm and other regional contribution activities. This rule was prescribed in the agreement signed between the power plant and Higashimatsuyama City in the course of the mega-solar power plant development project.

The site extends to approximately 6ha combining the mega-solar power plant and the eco-farm. Although the land is entirely private property, it has been positioned as part of the Saitama Eco-Town Project and has been fully supported by Saitama Prefecture and Higashimatsuyama City from the planning stage. On August 17, 2013, administration heads including Governor Kiyoshi Ueda of Saitama Prefecture, Mayor Koichi Morita of Higashimatsuyama City and Chairman Yoshikazu Oyama of the City Council were all present at the power plant's opening ceremony.

'Home of stink bugs' transforms into mega-solar plant

In fact, it was the complaints by citizens frequently filed to Higashimatsuyama City that precipitated the mega-solar power plant construction project. Oaza Matsuyama district in Higashimatsuyama City, where the mega-solar power plant and the eco-farm are located, was called the "home of stink bugs" by local people.

Matsuyama district had abandoned farmland that had been neglected partly because it was once used for industrial waste disposal. As a result, it became a wasteland filled with head-high grass, and there were frequent mass outbreaks of stink bugs that release a strong odor. Complaints such as "washed clothes and futons cannot be dried outside" were directed at the city. The city requested more than 20 landowners to weed the grass every time the complaints were made.

During Higashimatsuyama City's consultations regarding the use of Matsuyama district with Saitama Prefecture, the construction of the large-scale solar power plant started, led by the Smart Energy Group, which was familiar with some prefectural government employees. The project was also positioned as part of the Saitama Eco-Town Project that focuses on the spread of reusable energies.

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Generally, it is not easy to convert land categorized as farmland held by many landowners to hybrid and other categories. In the case of Matsuyama district in Higashimatsuyama City, however, in light of the difficulty of using the land for agriculture, the land category was quickly converted, with comprehensive assistance from the prefecture and the city, after construction of the large-scale solar power plant was proposed.

Ahead of the plant’s construction, the land's temporary use for industrial waste disposal became a challenge in terms of civil engineering work. Given the buried industrial waste, the land could not be dug deeper than 50cm, and full-fledged ground leveling was also difficult.

Based on these circumstances, a method that connects the foundations of the stakes under the soil using concrete was adopted when installing the mounting systems (Fig. 5). Leaving the undulations of the ground as they were, the panels were set up at the same height by varying the height of the concrete foundations.

As for the PV inverter, a TMEIC product boasting high conversion efficiency was adopted. But the plant purchased, remodeled and substituted second-hand containers for standard housing structures in a proprietary way (Fig. 7).

Amount of power generation exceeds estimates by 20%

"Thus far, the amount of power generation has surpassed the estimates by about 20%," Kihara said.

Should the efficiency of an overall system including PV inverters be conspicuously high, the amount of power generation could exceed estimates made based on the solar panel's power generation capacity.

"We would like to analyze the factors behind the upswing in the amount of power generation," Kihara said. "But it is possible that the power generation loss was diminished by the wind blowing through the area that prevents the panel temperature from rising."

In early August 2013, a schoolboy and his mother came to visit the power plant just before it was completed. The schoolboy said he wanted to study the large-scale power plant as the subject of independent research during his summer vacation. Despite being busy, Manager Kihara helped them, explaining as much as they needed.

"It was one of the greatest pleasures I had through the construction of a large-scale power plant," he said. "Should children, who will lead the next generation, become interested in solar power generation, even a bit, a mega-solar power plant in an urban zone can fulfill its duty."

The Higashimatsuyama Kagayaki Power Plant seems to be demonstrating how things should be for large-scale solar power plants.