[FAQ] Kyushu Electric Power Company Area / Online proxy curtailment (economic curtailment)
This page provides answers to frequently asked questions regarding online proxy curtailment (economic curtailment) in the service area of Kyushu Electric Power Company, Japan.
Questions Regarding The System
Q1. When will online proxy curtailment begin?
A. It is expected to be operational from December 2022.
Q2. Who is applicable?
A. Solar power generators between 10 kW and 500 kW will be newly applicable.
Solar power generators with a capacity of 500 kW or more, which have been subject to curtailment up to now, will continue to be included.
Q3. How does online proxy curtailment work?
A. This is a system in which an online power plant, which can be operated flexibly according to actual supply and demand, performs curtailment on behalf of an offline power plant, and monetary settlement is made two months after the month of curtailment.
[For off-line power providers] For power plants that have not installed online curtailment equipment
- Shutdown time: Each curtailment will be considered to be 8-hours. No work will be required to shut down the PCS on-site or remotely as in the past.
- Amount of electricity sold: The amount of proxy curtailment will be deducted from the amount of electricity sold in the month prior to the month of settlement and credited to the account in the second month following the month of suspension.
- Counting the number of days of curtailment: The number of days of proxy curtailment by the proxy curtailment provider plus the number of days when the station was actually curtailed due to local operations, are counted as the annual number of days of curtailment for that power provider.
[For online power providers] Power plants that have installed equipment that supports online curtailment
- Shutdown time: Since the original curtailment and proxy curtailment will be mixed, it is not possible to say how long a single shutdown will last. The originally curtailed portion will be curtailed for the same amount of time as the actual demand, and the proxy curtailment will be 8 hours per shutdown. As a result, it is assumed that there will be cases in which the total curtailment will be for 30 days or more.
- Amount of electricity sold: Two months after the month of curtailment, the amount of electricity sold for the previous month, the original curtailment amount, and the proxy curtailment amount are offset and credited to your account.
- Counting the number of days of curtailment: The number of days of proxy curtailment subtracted from the total number of days of curtailment is counted as the annual number of days of curtailment for that power plant.
Q4. Is there a difference in the curtailment time?
A. Yes.
For online power providers, the amount of control is determined 2 hours in advance according to the supply and demand situation of the day, so it will vary from day to day.
Off-line power providers are considered to be curtailed for 8 hours from 8:00 to 16:00, as in the past.
Q5. When will I be notified about the curtailment?
A. Online power providers will no longer be notified about the curtailment. Therefore, there will be no distinction between regular curtailment and proxy curtailment.
Off-line power providers will basically no longer be required to perform actual curtailment activity as it will be done by proxy curtailment.
However, for off-line power providers, there may still be some operations that require actual work for curtailment, as some operations will still remain.
In such cases, you will be notified by email or phone after 4:00 p.m. the day before.
Q6. If there is no notification to online power providers, does that mean we will not be able to distinguish between the portion that is originally curtailed and the portion that is proxy curtailment?
A. Yes, that is correct. The distinction will not be reported on the monthly purchased power billing statement (web, postcard, etc.).
Q7. How and when will we know the amount and value of proxy curtailment?
A. As answered in Q.5 and Q.6, it is not possible to distinguish between proxy curtailment and original curtailment.
Payments are made by the power company to which electricity is sold, and information on the proxy curtailment (amount of electricity and amount of payment) can be confirmed in the electricity sales statement notification (web, postcard, etc.) at the time of payment two months after the month in which the proxy curtailment is made.
Q8. From what month to what month does the 30-day rule apply?
A. From April of that year to March of the following year.
Q9. What is the reason for the decrease in the number of curtailment in FY2022 compared to FY2021 and before?
A. We assume that a major factor, especially in the Kyushu area, is the progress of on-line curtailment.
As online curtailment expands, flexible adjustments closer to actual demand can be made, which is expected to reduce the amount of curtailment compared to the current operation.
For example, if online proxy curtailment is introduced in the Kyushu area, where curtailment is already in place, it is expected to reduce the overall amount of renewable energy output curtailment by about 20% compared to the current situation.
Technical Questions
Q1. Should I choose proxy curtailment or online curtailment?
A. Given the respective curtailment period, it is assumed that the loss of electricity sold would be less if an online curtailment system is installed.
Q2. How long will it take to recover the cost of modification to bring PCS online?
A. It varies depending on the size of the power plant and the number of times curtailment is implemented, but from our company’s past experiences, it is usually recovered in about two years.
Q3. Will there be cases where the annual limit of 30 days under the old rule will be exceeded?
A. Since online power providers will be controlling a mixture of original curtailment and proxy curtailment, it is expected that the control may exceed 30 days.
(The original curtailment period will not exceed 30 days.)
On the other hand, off-line power providers will not be curtailed for more than 30 days in accordance with the 30-day rule.
Q4. What are the benefits of online proxy curtailment?
A. For off-line power providers, it eliminates the need for manual control (or remote control). In addition, online proxy curtailment allows for flexible adjustment to meet actual demand supply, which not only reduces the amount of curtailment for the entire Kyushu area, but also avoids unnecessary suspension of power generation.