Japanese Towns Switch to Microgrids

by James Wilson
April 4, 2018

Many towns in Japan are shifting to independent, decentralized power systems to better prepare for disasters.

The 2011 Great East Japan Earthquake, and the tsunami that followed, destroyed three-quarters of the homes in Higashimatsushima, a town of about 40,000 people located in the Tohoku region of Japan. More than a thousand of the town’s residents were killed.
In the time since the disaster, the city, in partnership with housing developer Sekisui House, rebuilt itself as a model of resilience and sustainability. In June 2016, Higashimatsushima City Smart Disaster Prevention Eco Town officially opened. Funded by Japan’s Ministry of Environment as part of the country’s national resilience program, the community includes 70 new houses and 15 new apartment buildings—all designed to be earthquake resistant and energy efficient.

Aiming for net-zero

Higashimatsushima’s officials are planning to make the city net-zero energy by 2022. The town currently has 460 kW of solar capacity, 480 kWh of battery storage capacity, and a backup 500 kW biodiesel generator. Smart meters track total energy generation, storage, and use.

The town’s renewable capacity has grown rapidly since 2011, increasing by a factor of about 20 in four years. By 2026, the town plans to produce 120% of its energy demand with renewables.

In the event of another disaster that causes the main electrical grid to fail, Higashimatsushima’s microgrid can power the entire town for several hours, or redirect energy away from residences to power hospitals and community centers for several days.

Transforming Japan’s energy sector

In the years since the 2011 earthquake, communities in a number of cities—including Kashiwanoha and Ashiya—have taken similar action to that of Higashimatsushima, setting up decentralized microgrids so that they can power themselves for days independent of the main grid if another disaster damages the nation’s energy infrastructure.

The Japanese government, in support of the replication of this model in cities across the nation, has announced that funding for the National Resilience Programme will be increased 24%. Japan currently relies on fossil fuel imports for 94% of its power but has set a goal for 22%–24% of its energy to be from renewable sources by 2030. The country sees the development of local microgrids like the one at Higashimatsushima as crucial to the transition to a clean and reliable energy system.

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