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Microgrid Introduced in Disaster-hit Area Along With PV System, Battery (1)

City owns power transmission cables

2016/08/22 12:04
Kenji Kaneko, Nikkei BP CleanTech Institute
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Higashi-Matsushima City is located roughly at the center of Miyagi Prefecture and enjoys a beautiful coastline. The city was formerly visited by more than one million tourists every year for swimming and enjoying trips on sightseeing boats. About 65% of the city area was damaged by the tsunami after the Great East Japan Earthquake, and 11,073 houses, which correspond to about 73% of all houses in the city, were destroyed or partially damaged. The number of dead and missing totaled 1,134, and the number of evacuees peaked at 15,185.

During power failures, power is supplied from solar power systems and diesel generators

The person in charge at the Disaster Recovery Section of Higashi-Matsushima City expressed his/her regret saying, "Although we established a disaster prevention plan in preparation for a tsunami before the great earthquake, we did not estimate that such a wide area would be flooded." The population before the earthquake was 43,142, but it decreased to 40,138 (as of April 2015). The number of tourists is now only about 200,000 per year.

Reflecting on the inadequate disaster prevention measures, the city has been promoting recovery measures with a focus on construction of a city resistant to disasters. One of such measures is the "Higashi-Matsushima City Smart Disaster Prevention Eco Town" (Fig. 1). After the disaster, power failures continued for five and a half months, and many people died of hypothermia caused by the lack of heating. Based on the lessons learned from the experience, the city aimed for a decentralized, locally governed energy system independent from the power grid.

Fig. 1: Overall view of "Higashi-Matsushima City Smart Disaster Prevention Eco Town" (Source: Sekisui House)

Eighty-five public housing units built after the disaster were constructed in the Yanaginome-kita district of the city. A solar power generation system (470kW), a stationary lead storage battery (480kWh) and a bio-diesel generator for emergency use (500kVA) were constructed in the town (Fig. 2 & 3). Even if a power failure occurs in the grid of Tohoku Electric Power Co Inc, a normal level of power can be supplied for several days.

Fig. 2: The solar power plant installed in the Eco Town (Source: Nikkei BP)

Fig. 3: Lead storage batteries are stored in the cabinet. (Source: Nikkei BP)