FUKUOKA -- Japan's Environment Ministry is partnering with a regional electric utility to conduct the country's first test of tidal power -- electricity generated by harnessing the ebb and flow of the ocean's tides -- starting in February 2021.
The test, to be conducted with a Kyushu Electric Power Co. subsidiary, may pave the way for the full-scale introduction of tidal power as a mainstream renewable energy option as the Japanese government looks to meet its pledge to go carbon neutral by 2050.
Electricity is generated by placing large turbines in the sea, which are turned by the twice-daily coming and going of the tides. Unlike wind or solar power, which are impacted by the changing weather, the tides follow a regular cycle, and so provide a predictable flow of energy. Furthermore, there are many spots in Japan with tidal flow speeds of 1 meter per second or more needed to make tidal power practical.
However, research and development into the technology ground to a virtual standstill in the 1990s as thermal and nuclear power generation took top priority. As a result, there has never before been a large-scale test of tidal power for commercial purposes in the country.
The Environment Ministry launched a project considering swift commercialization of tidal power in 2014, initially seeking to have a domestic manufacturer build the turbines. However, the partner firm effectively withdrew due to the low profit margin on the project. For this reason, the ministry will be using a turbine produced by a British firm already making commercial tidal power turbines.
The 25-meter-tall, 500-kilowatt test generator -- which is scheduled to arrive in mid-December -- will be installed on the sea floor some 40 meters below the surface in the Naruseto Strait in the Goto Islands, part of southwestern Japan's Nagasaki Prefecture. The strait sees tidal flow speeds of up to 3 meters per second.
The test will seek to evaluate the turbine's performance and generating capacity, while also providing the chance to see how to manage related legal procedures and address local community concerns. There is a heavy concentration of shipbuilding-related industry in Nagasaki, and the project will also look at how tidal power station maintenance could contribute to the local economy.
At present, the most practical application of the technology in Japan looks to be powering distant island communities already separated from mainland power grids. Most of these communities get their electricity from diesel generators, so switching to tidal energy would cut their greenhouse gas emissions. However, cost remains a major issue. Solar and wind energy typically runs about 20 yen (around 19 cents) per kilowatt-hour, but tidal energy costs more than twice that. One aim of the test project will be to find ways to make energy production more efficient.
Kyuden Mirai Energy Co., the Kyushu Electric subsidiary that will run the turbine, stated, "We currently do not have any of the knowhow needed to install and run the generator. So the first thing we need to do is collect foundational information, with the aim of having the turbine in service for 30% of the time, which is said to be the average." The test is scheduled to continue until the end of March 2021, but the Environment Ministry is considering extending the period.
(Japanese original by Yoshihiro Takahashi, Fukuoka Business News Department)