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Output Control Rate of 5% or Less, Real-time Control Are Essential, Expert Says (page 2)

2019/06/24 20:28
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Labo
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Ratio 2 to 3% in Spain

Q: However, output control was executed 17 times in March and 19 times in April this year, and the frequency increased sharply. If the frequency continues to increase at this speed, it is possible that the frequency reaches the upper limit of the "30-day rule," which is 30 days per site.

Yasuda: The number of days on which output control was executed increased sharply in March and April, but the output control rate cannot be estimated based on the number of days alone, and therefore, I cannot evaluate the situation at this stage. The output is controlled only during the period around noon, when balancing the supply and demand is the most difficult, in some cases, because Kyuden can control large-scale solar power plants by remote operation. It is possible that the controlled amount is not so large as the amount you imagine from the number of days.

In any case, we hope that the output control rate data is disclosed as soon as possible. The data is normally disclosed one month after output control in Japan, but the control amount is sometimes disclosed on the next day in some overseas countries.

Q: An expert meeting of the Ministry of Economy, Trade and Industry (METI) (New Energy Subcommittee, Grid Working Group) indicated that the output control rate will be 10 to 20% for the "rule for designated power producers" that connect their power plants to grids under the limitless and no compensation output control conditions based on the estimated value for calculating the connectable amount (30-day equal output control framework) in some cases when solar power introduction is accelerated.

Yasuda: It was indicated that the output control rate in Japan is 8% at maximum for power producers covered by the "30-day rule" while it is likely that the rate could be double figures for power producers covered by the rule for designated power producers. From the global viewpoint, it is unlikely that the output control rate rises to this level following introduction of large-scale renewable energies.

For example, in Ireland, which is similar to Hokkaido in area, population, demand for power and grid scale, the ratio of renewable energies mainly consisting of wind power reached 30%. The introduction amount is about 20 times that of Hokkaido, but the output control rate is only slightly more than 5%.

The output control rate of "5%" is comparatively high in Europe, and the rate is as low as 2 to 3% in Spain (Fig. 1). The consensus in Europe, where wind power and solar power were introduced earlier than other countries, is to keep the output control rate to around 5% by accumulating knowhow on grid operation. The EU directive specifies minimization of the output control amount.

Fig. 1: Comparison of output control in each country (source: Information of the Grid Working Group of METI)