Vận hành, TOU & quản lý năng lượngOperation, TOU & energy management · BàiLesson 1/4
Time-of-Use Tariffs and Battery Charge/Discharge Settings
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Solar Knowledge HubBiểu giá theo giờ và cài đặt sạc xả pinTime-of-use tariffs & battery charge-discharge settings
Biểu giá TOU biến pin lưu trữ thành công cụ tiết kiệm tiền: sạc lúc giá rẻ, xả lúc giá đắt.TOU tariffs turn a battery into a money-saving tool: charge cheap, discharge expensive.
| Khung giờTime band | Giờ áp dụngHours | Lưu ýNote |
|---|---|---|
| Thấp điểmOff-peak | 00:00 – 06:0000:00 – 06:00 | Thứ hai tới thứ bảyMon – Sat |
| Cao điểmPeak | 17:30 – 22:3017:30 – 22:30 | Thứ hai tới thứ bảyMon – Sat |
| Bình thườngNormal | 06:00 – 17:30 và 22:30 – 24:0006:00 – 17:30 and 22:30 – 24:00 | Thứ hai tới thứ bảy; chủ nhật cả ngàyMon – Sat; Sunday all day |
| Khung giờTime band | Khách kinh doanhCommercial | Khách sản xuấtProduction |
|---|---|---|
| Cao điểmPeak | 5.422 đ/kWh5,422 VND/kWh | 3.640 đ/kWh3,640 VND/kWh |
| Bình thườngNormal | 3.152 đ/kWh3,152 VND/kWh | 1.987 đ/kWh1,987 VND/kWh |
| Thấp điểmOff-peak | 1.918 đ/kWh1,918 VND/kWh | 1.300 đ/kWh1,300 VND/kWh |
Giá cao điểm cao gấp gần ba lần giá thấp điểm cho khách kinh doanh. Mỗi kWh pin xả đúng giờ tiết kiệm tối đa phần chênh lệch đó, sau khi trừ hao 8–15% mỗi vòng sạc xả.Peak price is nearly three times the off-peak price for commercial. Each kWh discharged at the right hour saves the full gap, minus 8–15% round-trip loss.
Mỗi vòng nạp xả qua pin hao khoảng 8–15%. Với chênh lệch 3.500 đ/kWh của khách kinh doanh, sạc lúc rẻ xả lúc đắt vẫn rất có lời. Nếu chênh lệch nhỏ, lợi nhuận sau hao có thể không đáng: luôn tính tổn hao vào bài toán arbitrage.Each charge-discharge cycle loses about 8–15%. With the commercial 3,500 VND/kWh gap, arbitrage is very profitable. If the gap is small, post-loss gains may not be worth it: always include round-trip losses in the calculation.
Chỉ cho khách thấy giá cao điểm gần gấp ba thấp điểm, pin xả đúng khung 17:30–22:30 tiết kiệm rõ. Luôn dùng giá EVN hiện hành và khung giờ mới theo Quyết định 963 khi lập phương án; khung giờ cao điểm đã dời hẳn về buổi tối, không còn buổi sáng.Show customers the peak is nearly three times off-peak, battery discharge 17:30–22:30 is the savings engine. Always use current EVN rates and the new schedule from Decision 963; the morning peak no longer exists.
Time-of-use (TOU) electricity tariffs are the mechanism that turns a battery storage system into a money-saving tool. When electricity prices vary by time slot, a battery can charge when rates are cheap and discharge when rates are expensive, capturing the price difference. This document covers the three time slots and their rates under the current regulation, the operating strategy, and how to configure the inverter accordingly.
For: inverter installation technicians, sales staff calculating savings for commercial customers, and newcomers who need to understand time-of-use tariffs.
Quick summary
TOU tariffs divide the day into three windows. Under the new schedule effective 22 April 2026, off-peak runs from midnight to 6:00 AM, peak runs from 17:30 to 22:30 Monday through Saturday, and everything else is the normal period. Sunday is billed at the normal rate all day: there is no peak window on Sundays.
The price gap between peak and off-peak is the savings opportunity. For commercial customers below 6 kV, the gap is approximately 3,500 VND per kWh; for production customers it is approximately 2,340 VND per kWh.
The core strategy is to charge the battery during off-peak hours and from daytime solar surplus, then discharge into the evening peak to avoid the expensive rate. Inverter settings must be configured to match these time windows exactly.
The three time slots and their rates
TOU tariffs apply to commercial and production customers, dividing the day into three windows. Under Decision 963, effective 22 April 2026, the schedule is as follows. Off-peak runs from 00:00 to 06:00. Peak runs from 17:30 to 22:30 Monday through Saturday. Normal covers the remainder: 06:00 to 17:30 and 22:30 to 24:00. Sunday is treated as normal all day with no peak window.
Rates under Decision 1279, excluding VAT, differ between the two customer groups at voltage levels below 6 kV.
| Time slot | Commercial customers | Production customers |
|---|---|---|
| Peak, 17:30 to 22:30 | 5,422 VND/kWh | 3,640 VND/kWh |
| Normal | 3,152 VND/kWh | 1,987 VND/kWh |
| Off-peak, 00:00 to 06:00 | 1,918 VND/kWh | 1,300 VND/kWh |
The original document contained two errors that have been corrected. The normal-period start time for commercial customers was recorded as 04:00; the correct time is 06:00, as confirmed by the source image and the regulation text. The off-peak rate for production customers was recorded as 1,146 VND: that figure applies to the 110 kV and above voltage tier; the correct rate for the below-6 kV tier is 1,300 VND. Consequently, the production-customer price gap is 3,640 minus 1,300 = 2,340 VND/kWh, not 2,494.
Hourly operating strategy
The TOU principle is straightforward: charge when cheap, discharge when expensive. In practice this breaks into four windows across the day. During the off-peak window from midnight to morning, charge the battery from the grid at the low rate. During the normal daytime window, prioritise solar power for the load and charge the battery from any surplus generation. During the evening peak window, discharge the battery to serve the load and avoid the high rate, minimising grid draw. During the late-evening normal window, use the grid or charge lightly to prepare for the next day’s cycle.
Commercial customers have the largest price gap and therefore benefit the most from discharging into the peak window. This makes large-capacity battery investment attractive and shortens the payback period. Production customers face a moderate gap and should discharge flexibly (between 70% and 100% depth of discharge depending on load), balancing peak avoidance with uninterrupted production. A moderate battery investment is appropriate.
The price spread must be large enough to outweigh round-trip losses in the battery. As covered in document 03-04, each charge/discharge cycle through a battery storage system incurs losses of roughly 8 to 15 percent. With the 3,500 VND/kWh spread available to commercial customers, price arbitrage is highly profitable. However, if the spread is small, the margin after accounting for round-trip efficiency losses may not be worthwhile, so always include storage losses in any arbitrage calculation.
Configuring TOU settings on the inverter
Configuration means mapping the time windows above into the inverter’s charge/discharge schedule. A sample configuration for a commercial customer is as follows. The 00:00–06:00 window: set the inverter to charge from the grid at a high rate, capturing the off-peak tariff. The 06:00–17:30 window: set priority to solar power serving the load, with battery charging from surplus generation. The 17:30–22:30 window: set the inverter to discharge the battery to serve the load, avoiding the peak rate. The 22:30–24:00 window: use the grid or charge lightly to prepare for the next cycle.
Production customers use a similar configuration but with flexible discharge depth (typically 70 to 100%), adjusted according to the production load, so peak costs are reduced while continuous operation is maintained.
For commercial customers, the strongest selling point is the time-of-use price gap. Show the customer that the peak rate is nearly three times the off-peak rate, so discharging the battery squarely into the evening peak window produces clearly visible savings. Always use the current EVN tariff when preparing a proposal, since rates are updated periodically, and always configure the correct time slots under Decision 963: the peak window has shifted entirely to the evening.