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Japan Plans to Employ 'Economic Method' for Output Control of Solar Plants

2019/07/09 17:47
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Labo
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Japan's Ministry of Economy, Trade and Industry (METI) discussed future output control of solar power plants at a meeting of the Subcommittee for Introducing Large Amount of Renewable Energy and Next-generation Power Network July 5, 2019.

METI showed a plan to (1) encourage less-than-500kW commercial solar power plants, on which METI has not imposed output control, to voluntarily introduce online control devices and (2) employ an "economic method." And the plan was approved by all the subcommittee members.

At a meeting of the Grid Working Group (WG) of New and Renewable Energy Subcommittee in April 2019, METI announced that it will apply output control to less-than-500kW (10kW-or-higher output) commercial solar power plants connected to power grids under the previous rules, which were considered as being "exempted from output control for the time being."

As a result of this measure, in the service area of Kyushu Electric Power Co Inc, the number of solar power plants that are the targets of output control will increase from the current about 26,000 (4,710,000kW) to about 91,000 (6,820,000kW) (an increase of 65,000 or 2,110,000kW).

However, it is not possible to obligate the less-than-500kW commercial solar power generation (PV) facilities that were connected to power grids under the previous rules to install online output control devices. So, for actual output control, METI will encourage power producers to visit the sites, remotely stop operation from 9:00 to 16:00 or voluntarily introduce devices enabling power companies to control output online.

Many less-than-50kW commercial low-voltage solar power plants are often run by a single power producer. So, it is not realistic that power producers can manually stop and restart those plants. Therefore, METI is promoting the introduction of online control devices as in the case of PV facilities connected under the new rules. However, expecting that many power producers will not introduce the devices, METI decided to employ output control using the economic method.

The economic method for output control uses a mechanism that separates (1) sites that actually control output from (2) sites that decrease the amount of power generated (sold). Specifically, mainly large-scale sites capable of online control will reduce output by stopping PV inverters so that the economic losses of all the sites responsible for output control will become even in the end.