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.
Choosing ‘online’ or ‘economic method’
METI has not disclosed the specific schedule for output control of less-than-500kW commercial solar power plants connected under the previous rules. But it plans to (1) decide a method to calculate lost profits, which is necessary for the economic method, in one or two years and (2) implement output control by enabling to select online control by a power company or the economic method.
According to METI’s estimates, if the output control is also applied to less-than-500kW commercial solar power plants connected under the previous rules in the service area of Kyushu Electric, the number of days for which output control is applied to each solar power plant will decrease by about 30% from 8.5 to 5.9 per year. It will increase fairness among power producers and decrease the frequency of output control for newly-connected power plants, contributing to further introduction of solar power plants, according to METI.
In addition, as for higher-than-500kW-output (large-scale) plants that were connected to high-voltage or extra-high-voltage power transmission lines and are operating under the previous rules, METI plans to encourage them to shift to online control. So, it will encourage high-voltage plants to introduce control devices in addition to extra-high-voltage plants, most of which have already shifted to online control.
According to METI, in the service area of Kyushu Electric, only 1,720,000kW of about 4,780,000kW of solar power plants responsible for output control use online control. In the case of online control, it is possible to cancel output control on the day, decreasing the amount of output control. According to an estimate, if all the power plants responsible for output control adopt online control, the necessary amount of output control will decrease by about 30%.
Source:project.nikkeibp.co.jp
