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Output Control Rate of 5% or Less, Real-time Control Are Essential, Expert Says

2019/06/24 20:28
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Labo
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The first output control on the mainland was executed in Kyushu Oct 13, 2018. The frequency of the control was seven days in total over two months from October to November of that year. The frequency increased sharply this year to 16 days in March and 19 days in April. Because the power cannot be sold during the period when the power output is highest, power producers are concerned about a decline in the business feasibility and are beginning to refrain from new developments in the Kyushu area.

We interviewed Project Professor Yo Yasuda of the Graduate School of Economics at Kyoto University, who is familiar with output control in overseas countries.

'More renewable energies can be introduced by output control'

Q: Output control in the areas covered by Kyushu Electric Power Co Inc (Kyuden) has been increasing sharply since this spring, and the power generated by renewable energies is wasted without being used, which is sometimes criticized.

Project Professor Yo Yasuda of the Graduate School of Economics at Kyoto University (picture: Nikkei BP)

Yasuda: I would like to point out first that the need for the "output control," an operation method of renewable energies and the issues on output control in Japan should be discussed separately.

In Japan, criticisms are often heard about the output control executed by Kyuden for the first time on the mainland. However, the output in low-load periods in the daytime is generally controlled throughout the world for grid operation in the process of introducing large-scale solar power and wind power. The solar power and wind power introduction amount can be increased by temporarily controlling the output, which is a common perception.

Q: Power companies including Kyuden recently began to emphasize the theory of "increasing the amount of renewable energy introduction by output control", but power producers often say, "The stopping of output in spring, when the power generation amount is the highest among the four seasons, is a serious problem for us."

Yasuda: I understand their opinion, but construction of second and third power stations for example, following the first one, will be possible if they accept a certain level of output control, based on the assumption that many more solar power plants need to be constructed in Japan. Power producers who say "output control is absolutely unacceptable" are talking on behalf of vested interests of existing solar power plants.

If the business feasibility was severely damaged by the level of the output control by Kyuden in fiscal 2018, there was a problem in the initial business plan of the power plant.

Solar power producers in Japan agree to the "30-day rule," which is a rule to accept output control up to 30 days with no compensation, for grid connection. The amount corresponds to approximately 8% in the output control rate (power loss ratio). The output control rate in fiscal 2018 is estimated to be less than 1% (Kyuden disclosed that the rate was 0.9% after the interview), and there is a lot of room to increase the rate.

The media targeting the general public tend to report verbatim the pessimistic views of power producers regarding the output control by Kyuden and they are making a big deal about the impact of output control.