Disaster-hit Golf Course Redeveloped as Solar Plant

Expertise in mega-solar power plant to be applied to urban building business

2014/02/01 21:02
Shinichi Kato, Nikkei BP CleanTech Institute

"Mori Trust Energy Park Izumizaki" is a mega (large-scale) solar power plant in the mountains of Izumizaki-mura, Nishi-Shirakawa-gun, Fukushima Prefecture. It is located about 6.1km from Yabuki IC on the Tohoku Expressway and 6.7km from Izumizaki Station on the JR Tohoku Main Line. The site was originally run by the Mori Trust Group as "Laforet Shirakawa Golf Course." After being hit by the Great East Japan Earthquake in March 2011, the mega solar power plant was constructed on the site to start selling electricity to Tohoku-Electric Power Co Inc.

Along with the former Laforet Shirakawa Golf Course, Mori Trust holds a number of other properties in the region hit by the Great East Japan Earthquake, such as the "Sendai Trust Tower," an office building in Sendai City, Miyagi Prefecture, and the resort hotel "Laforet Zao Resort & Spa" in Zao-machi, Katta-gun, Miyagi Prefecture. And it runs various businesses including building lease and hotel management. Given that it has many businesses closely tied with local communities, Mori Trust has advocated the policy of continuing its businesses in these disaster-struck areas and making contributions to the recovery of each area.

The former Laforet Shirakawa Golf Course was forced to stop operation after the Great East Japan Earthquake because it was difficult to restore the golf course due to the landslides and cracks in the ground caused by the earthquake. In the search for a business that could continue in such an area, Mori Trust decided to shut down the golf course and enter the electric power selling business based on a mega solar power plant.

Starting from 2MW, which can be transmitted via existing high-voltage line

As for the Mori Trust Energy Park Izumizaki construction project, a mega solar power plant with a total output of 10MW will be built in two phases: 2MW in Phase 1 and 8MW in Phase 2. A total of approximately ¥4 billion (approx US$39 million) is slated for investment.

The 2MW solar power system set up in Phase 1 started selling power in August 2013. Roughly 10,000 solar panels were installed in about 6.4ha (64,000m2), which is equivalent to two holes on the golf course (Fig 1 & 2). The expected amount of power generation is approximately 2,300,000kWh per annum, which corresponds to the annual power consumption of 700 average families.

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The 8MW-capacity Phase 2 solar power generation system will cover almost every available part of the remaining area of the golf course. It has not been determined when Phase 2 area will start selling electricity. The expected amount of power generation is about 9,200,000kWh per annum, which corresponds to the annual power consumption of 2,800 average families.

The output of the Phase 1 area was set at 2MW because it was the maximum amount that could be transmitted through the existing overhead high-tension power transmission line of the golf course almost as it is. As for the 8MW output of the Phase 2 area, the generated power cannot be sold until Tohoku Electric Power establishes extra-high-tension power transmission lines. As extra-high-tension power transmission lines have not been established around the golf course, which is in the mountains, the lines will have to run for a long distance.

Installation cost reduction, measures against snow cover

The Phase 1 solar power generation system with 2MW output was set up at the former holes No. 6 and No. 7. As these holes stretch east to west, many of the solar panels can be set up facing south, which is the best direction for solar power generation. In addition, the extra cost required for installation is small, and the holes are located near the high-voltage lines.

In an effort to lower the installation cost, as many of the trees as possible were left in the former golf course to save on the costs involved in cutting them down (Fig. 3 & 4). The deployment of an installation method that requires neither a concrete foundation nor the flattening of the ground also helped to lower the installation cost.

To maximize the amount of power generation while keeping as many trees as possible, the panels were arranged so the trees would not shade them. The mounting system is held with concrete stakes that require no foundation. By arranging the height of the mounting systems, the solar panels face south regardless of the golf course's undulations.

Although Nishi-Shirakawa-gun in Fukushima Prefecture is not a heavy snowfall area, measures against snow cover were still needed assuming the annual maximum depth of snow cover (15cm). Most solar panels that are generating power can become as warm as about 25°C when the ambient temperature is 5°C. Therefore, though a little snow may have accumulated on the surface, the snow should melt after the sun comes out. The measures were considered in case the snow still did not completely melt.

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At some solar power plants in heavy snowfall areas, solar panels are tilted at 30° or more so that snow slips off them. As Nishi-Shirakawa-gun, Fukushima Prefecture, does not have that much snow, the solar panels were tilted at 20°. The aim was to install the number of solar panels that can secure the expected amount of power generation in limited areas where solar panels can be set up without additional development.

Tilted at 20°, solar panels seldom shade neighboring panels even in the morning and evening when the sun is low and makes shadows longer, securing greater annual power generation. The standard height of solar panels was set at 60cm from the ground.

In addition, the design allows snow accumulated on the panels to slip off from the 20cm space set between the upper and bottom sides of the neighboring panels (Fig. 5).

The manufacturers of the solar panels and PV inverters used for the Phase 1 solar power generation system with 2MW output have not been revealed. But two manufacturers' solar panels were adopted in Phase 1. This was for the purpose of verifying the panels for the Phase 2 construction and for consideration such as in introducing reusable energy to Mori Trust's urban building business in the future.

Based on discussions by the Innovation Business Department at Mori Trust Hotels & Resorts Co Ltd (Shinagawa-ku, Tokyo), the latest mega solar power plant was designed to be profitable by leveraging the group's knowledge and management resources.

The Mori Trust Group said it will make the most of its experiences and knowledge acquired through this mega-solar power plant, approaching reusable energy-based power generation as a key issue along with the improvement in energy-use efficiency in its existing urban building business.

Among its urban buildings, Mori Trust accepted a total of about 3,600 displaced people to the Sendai Trust Tower, which is equipped with an emergency power generator, when the earthquake struck the region. The company’s Kyobashi OM Building, recently constructed in Chuo-ku, Tokyo, is equipped with an emergency power generator with a capacity equivalent to the weekly power consumption of the entire building as well as a stand-alone system combining solar panels and rechargeable batteries.