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The Yomiuri Shimbun Solar panels are installed on the rooftop of the public facility on Kozu Island, Tokyo.
By Kotaro Shibuya / Yomiuri Shimbun Staff Writer
16:51 JST, January 9, 2023
Generating renewable energy such as solar and wind power is becoming more common on remote islands across Japan with the aim of securing electric power in case of disasters, as well as reducing greenhouse gas emissions.
The central and local governments are beginning to support such attempts, and some companies are also starting to focus their attention on the islands as a new research and development base for renewable energy.
Lights during outage
Kozu Island, which belongs to Tokyo but is about 170 kilometers from the capital, was hit by a typhoon on Oct. 11, 2019. Strong winds blew at speeds of nearly 50 meters per second and the entire area was without power for about six hours in the evening. About 70 people evacuated to a community center on the island, which was equipped with solar panels and storage batteries. There, the evacuees had lighting and fans to keep them cool.
“The night storm cut the power and I was feeling faint, but I was relieved to see the lights on,” said a 72-year-old woman who runs a guest house on the island.
The island used to rely on diesel power generation, but in 2017, solar power was installed at public facilities in anticipation of a disaster or bad weather that would make it impossible to procure fuel oil from off-island sources.
“It’s very useful because typhoons and power outages come to us as a set every year,” said a municipal official.
A survey conducted in 2019 by the Land, Infrastructure, Transport and Tourism Ministry showed that of 254 surveyed remote islands, 59 have installed renewable energy generators in public facilities, doubling from 27 islands in 2012.
According to electric power companies, the amount of renewable energy generated is on the rise on remote islands, which are separated from mainland power grids. The growth has been particularly large in the Okinawa Electric Power Co.’s service area, due to the large number of remote islands. The amount of electricity generated from renewable sources in the area reached 60,390 kilowatts as of the end of August last year, an increase of about 27% from three years ago.
Power from tidal currents
The central and local governments are also encouraging the introduction of renewable energy to remote islands. Last September, the Tokyo metropolitan government launched a program to subsidize three-quarters of the cost (up to 100 million yen) for residents who install solar power generation facilities on remote islands. It received about 60 inquiries.
The Environment Ministry and the Okinawa prefectural government are publicly inviting businesses to utilize renewable energy on remote islands and subsidizing the installation costs.
In fiscal 2024, Japan’s first large-scale tidal current power generation will begin in the waters surrounding Naru Island in the Goto Islands, the western part of Nagasaki Prefecture, with assistance from the environment ministry.
A generator will be installed on the seafloor at a depth of about 40 meters with a propeller about 20 meters in diameter. The propeller will be rotated by the rising and falling tides to generate electricity, which will be supplied to the surrounding islands.
According to Fukuoka-based Kyuden Mirai Energy Co., the operator of the project, the experiment showed that it could generate electricity even if a typhoon hits the area directly.
“We’d like to develop new businesses on other islands by utilizing the knowledge we have gained here,” said an official at the company.
On Kume Island in Okinawa Prefecture, an experiment will start for wave power generation by a private company this summer. The device floats on the surface of the sea, and when it is raised or lowered by the movement of waves, the fresh water inside turns a turbine to generate electricity. The company aims to put the system into practice in three years.
Concerns about maintenance
However, the cost of installing and maintaining large-scale renewable energy facilities is huge. Without the help of companies, it is difficult to achieve this on remote islands with many small municipalities.
Izu Oshima Island, located south of central Tokyo, plans to begin experiments with offshore wind power generation in fiscal 2026, but has yet to find a participant company because of the cost, which is more than 2 billion yen per unit.
“Without the support of a company, we’ll have no choice but to rethink our plan,” said a municipal official.
In the land ministry’s 2020 survey, many municipalities cited cost burdens as a hurdle to introducing renewable energy. Another issue cited was the time required for repairs in the event of problems at facilities due to inconvenient transportation.
“For remote islands, it’s vital to have a stable independent power source in case of isolation due to disasters and other mishaps, so the central government should encourage the municipalities with subsidies,” said Hikaru Hiranuma, a senior fellow at the Tokyo Foundation for Policy Research. “In addition, it’s important for local governments on remote islands to develop the projects so that they can attract investment from companies.”
