Visit to Plant

1.7MW Solar Plant Minimizes Loss From Blackout Through 'Frequent O&M'

'Unit-type' float mounting system commercialized, supporting double-sided panels

2020/03/17 15:48
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Labo
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Survives heavy rain, violent winds

Chiba Prefecture was originally known as an area with relatively fewer natural disasters than other areas. In the summer of 2019, however, the prefecture was struck by both Typhoon No. 15 and No. 19, followed by a low pressure system accompanied by heavy rain on October 25.

Amid such circumstances, the "Mobara Solar Utopia," a mega- (large-scale) solar power plant with an output of about 1.7MW in Mobara City, Chiba Prefecture, Japan, withstood such natural disasters and successfully limited loss in power sales to a minimum (Fig. 1).

Fig. 1: Panoramic view of Mobara Solar Utopia (source: Toyo Chemical Engineering)

Funded by 9 local companies

This power plant was funded and constructed by six local major companies on an idle site owned by Mobara City.

Solar panels manufactured by Yingli Green Energy Holding Co Ltd of China, PV inverters of Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) and mounting systems made by Clean Energy Corp of Australia were adopted. The plant valued these manufacturers as top companies that boast a large share in the global market (Fig. 2).

Fig. 2: Yingli Green Energy solar panels, TMEIC PV inverters, Clean Energy mounting systems adopted (source: Nikkei BP)

Power selling restored in 4 days after power outage

In Chiba Prefecture, power transmission infrastructure was extensively damaged by the strong winds of Typhoon No. 15, and the power outage continued across a broad area for over two weeks, extending to 17 days in some areas. Needless to say, solar power plants connected with power grids in this region could not transmit generated power during the power outage. Even if the plant sites themselves had not been damaged, the plants continued to earn no income from power selling under these circumstances.

According to Takashi Kitamura, operating executive officer and director of the New Business Development Division of Toyo Chemical Engineering Corp, during the power outage following Typhoon No. 15, TEPCO Power Grid Inc was too busy working on the disaster sites and scarcely provided any information about its restoration schedule.

Commercial solar power producers look to restore grid connection and power selling as soon as power transmission is restored in order to minimize opportunity loss. In the large-scale power outage in Chiba, however, there was no information about whether the power transmission had already been restored or when it would be in the area where the company's power plant was connected with a grid, he said.

Although "it took longer than two weeks at maximum" to restore power supply after the large-scale blackout in Chiba, the power outage period greatly varied by area, and it only took a few days in some areas. Among the solar power plants, some failed to restore their grid connections and missed power selling opportunities for days without knowing about the recovery of those grids they were connected with.

Toyo Chemical Engineering noticed such a risk and requested its local peers connected with the same grid as the Mobara Solar Utopia to "share the news as soon as power transmission is restored."

As a result, such an attitude to collect information proved effective, while the power grid with which the Mobara Solar Utopia was connected fortunately recovered quickly. The power plant could reportedly recover power selling in only four days since the power outage began, having restored grid connection immediately after hearing about the restoration of the power grid (Fig. 3).

Fig. 3: Loss in power selling limited to only four days even after large-scale blackout last summer (source: Nikkei BP)