This photo shows the Kagoshima Nanatsujima mega solar power plant operated by Kyocera Corp. and others since 2013 in the city of Kagoshima. (Courtesy photo of Kyocera Corp.)
FUKUOKA – In the Kyushu region of southwest Japan, there have been frequent cases where electricity generated from renewable energy sources such as solar power has gone unused. Some days as much as the equivalent of four nuclear reactors’ worth of generating capacity is wasted without being transferred. Why is this happening if the government is to strive for carbon neutrality by 2050 and make renewable energies the main source of energy?
In order to maintain a balance between electricity supply and demand, energy companies “monitor performance” and ask generating companies to temporarily reduce electricity production when electricity consumption is low. This is the case, for example, in spring and autumn when the use of air conditioning is reduced. If the supply-demand balance is disturbed by continuing to generate and send electricity despite low demand, this can, in the worst case, lead to a large-scale blackout.
For this reason, on days when an electricity surplus is likely, energy providers ask the generating companies to reduce their output in the following order: (1) thermal, (2) biomass, (3) solar and wind, (4) hydropower, Nuclear power and geothermal energy. This order was decided based on the cost of generating electricity and the ease with which the power can be adjusted.
The installation of solar power generation in Kyushu has advanced because of the geographic advantage of the area that is blessed with sunlight. The service division of Kyushu Electric Power Co. with an output of 10 million kilowatts is the only one in Japan that has implemented power control since October 2018.
The No. 1 (foreground) and No. 2 reactors of Kyushu Electric Power Co’s Sendai Nuclear Power Plant are seen in Satsumasendai, Kagoshima Prefecture on January 18, 2019. (Mainichi / Toyokazu Tsumura)
The number of days of output control in the 2018 financial year was 26 days in the six-month period from October and increased to 74 days in the 2019 financial year. In fiscal 2020, the number went down to 60 days because reactors # 1 and # 2 at the Sendai Nuclear Power Plant in Kagoshima Prefecture were shut down for about seven to eight months, but in fiscal 2021 it is expected to increase to 95 days that is roughly every fourth day on which a power plant has to reduce its output.
In particular, from March 19 of this year, when the plant’s four reactors went back to full operation (with a total capacity of 4.14 million kilowatts), to May 11, when the rainy season began in parts of Kyushu, production became more renewable Energies were shortened for a total of 37 days, or about 70% of that period.
During this time of year, the air conditioning and heating consumption decreases and the electricity demand drops to the range of 6 million to 8 million kilowatts. When the four reactors are fully utilized, there will be a large surplus of renewable energy on sunny days during the day. On April 18, a record 3.82 million kilowatts of renewable energy was throttled, the equivalent of four nuclear reactors.
A senior executive at Chopro Co., based in Nagasaki Prefecture, which operates 17 solar power plants in Kyushu, said resignedly: “Almost every day, some of our systems are no longer accepted (by the electricity companies). We shut down, there are still costs, so our profits go down. Most of all, it would be like throwing away the electricity we generate, so it’s a waste. ”
Kazuhiro Ikebe, President of Kyushu Electric Power Co., is seen in Chuo Ward, Fukuoka on December 22, 2020. (Mainichi / Tomohisa Yazu)
In short, the first “barrier” to the use of renewable energies was nuclear power plants. Kazuhiro Ikebe, President of Kyushu Electric Power Co., said, “If we can increase the operating rate of existing nuclear power plants, the cost of reducing CO2 emissions will be lower.”
If performance control continues, the government’s goal of making renewable energy the main source of energy will be a long way from being achieved. As for offshore wind power generation, which is expected to be a pillar of renewable energy alongside solar power in Japan, the Goto Islands in Nagasaki Prefecture in Kyushu are considered the second best location in the country after Hokkaido, but if current output remains in control, there is a risk that this opportunity will be lost.
Also in Hokkaido and the Shikoku region, where the introduction of renewable energies is progressing, a performance review is to take place as early as the 2021 financial year, so that this is no longer a problem only for Kyushu.
Another “barrier” to avoid wasting renewable energies is the lack of connection lines to transfer electricity to other regions in the event of a surplus. If there is sufficient capacity in the interconnection lines, even if there is an excess in Kyushu, it can be transferred to the main Japanese island of Honshu, where the demand for electricity is high, thus reducing waste.
For this reason, the national government has also started to increase the number of interconnectors. According to a proposal drawn up at the end of April by the Organization for the Supraregional Coordination of Transmission System Operators, Japan – a government-backed company – the state plans to double the transmission capacity of the Kanmon link between Honshu and Kyushu. and to build a new line connecting Kyushu and Shikoku. This will triple the transmission capacity between Kyushu and other regions. It also plans to lay additional interconnections between Shikoku and Kansai and Hokkaido and Tokyo.
Renewable energy generated in areas with sunlight, wind power and large fields is transported to urban areas with high electricity demands. Reinforcing the interconnectors is an essential part of making renewable energy a major source of electricity, but the Ministry of Economy, Commerce and Industry does not expect to start operations until the “second half of the 2030s,” according to ministry officials.
In addition, the principle of sharing construction costs was adopted, which will be up to 1 trillion yen (about $ 9.13 billion) for Kyushu alone, “in proportion to the benefits each energy company receives,” but the details are not yet known to have been completed. It will be a long time before renewable energies are not wasted.
Yukari Takamura, professor at Tokyo University’s Institute for Future Initiatives and an expert in renewable energy, said: “Now that the whole country is moving towards ‘decarbonization’, it is unreasonable to waste large amounts of renewable energy through production control. ”
In particular, Takamura said, Kyushu “clearly needs to start construction (interconnection lines) as soon as possible, taking into account the rise in solar energy and the future addition of more offshore wind energy.”
(Japanese original by Yoshihiro Takahashi, Fukuoka Business News Department)
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