Case Study:
Impact of Two-Component Tariffs for Manufacturing Facilities in Vietnam
Vietnamese manufacturing entities will soon have a new electricity tariff that explicitly charges them for the peak demand (in kW), as opposed to just energy consumption (in kWh). These new two-component tariffs will be in effect from July 2026 and a trial tariff has been issued now to support the transition.
The case study analyzes the load/demand of an hypothetical manufacturing facility, and evaluates the impact of the trial two-component tariffs relative to the current baseline tariffs
The analysis highlights the importance of quantifying the intuitive ideas (e.g., two component tariffs will drive reduction in system peak demand), and gain further insights into the economic value of private investments.
The study is divided into several sections
The sections below also include some of the prompts and Agentic AI outputs, as well as the insights derived from the analysis (a joint AI + human endeavor)
Background
Vietnam is moving away from the current single-component retail tariff (only charging for energy consumption in kWh), towards a tariff structure that includes two components: (i) a capacity charge (reflecting customer’s reserved or available capacity, e.g., kW or kVA) and (ii) an energy‐consumption charge (kWh).
Vietnam's new Electricity Law 2024 (No 61/2024/QH15, effective 1 February 2025) explicitly refers to tariffs with multiple components, which provides legislative backing for this reform.
Vietnam's Ministry of Industry and Trade and EVN are starting to pilot the new tariffs with the group of manufacturing customers with an average consumption of over 200,000 kWh/month.
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EVN Proposed Trial Tariff Methodology
On 10 October 2025, EVN proposed trial tariff rates for manufacturing entities. Unlike the Baseline tariffs (Ministry of Industry and Trade Decision No. 1279/QD-BCT dated 9 May 2025). which only have energy-only costs based on time of use components, the two component tariff is calculated as follows:
𝑇𝐶 =𝐶𝑝 × 𝑃𝑚𝑎𝑥 + 𝐶𝑎 × 𝐴𝑝
𝑇𝐶 : The total electricity bill of the customer is according to the electricity price of two components
𝐶𝑝: Unit capacity price, calculated in VND/kW/month
𝑃𝑚𝑎𝑥: Peak power for the month (kW) determined by the meter. Effectively, it is the average power during the integral period with the largest value of the month, the integral period is currently 30 minutes, in line with the granularity in the Vietnam Wholesale Electricity Market (VWEM)
𝐶𝑎 : Unit price of electricity, calculated in VND/kWh, that varies by the Time of Use (TOU) categories.
𝐴𝑝: Electricity demand used in the meter reading cycle (kWh) within the TOU categories.
Comparing Baseline and Proposed Trial Tariffs
Insights:
  • Across all voltage levels and time bands, energy rates under the trial tariff are roughly 30–38% lower than the baseline single-component rates
  • Customers with stable, high load factors (e.g., 24/7 industrial plants) will likely save overall (from the reduced TOU rates).
  • Seasonal or intermittent operations could face higher bills because they pay for capacity even in low-use months.
  • Customers with lower load‐factors (high Pmax relative to energy consumed) may see higher bills under the two‐component structure (because of the capacity charge) unless they manage peak demand better.
  • Customers with high utilization and good load‐factor might benefit (from the reduced TOU rates).
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Analysis of Factory Electricity Consumption
First, let's examine the load profile of a hypothetical manufacturing facility, connected at 22 kV voltage level to EVN.
Below is a time-series 30 min interval data for the whole year for the facility, as well as the Load Duration Curve.
(developed using XanhTerra's AI analytics tool)
XanhTerra AI Prompt and Execution Plan:
Results from the Agentic AI analysis:
Insights:
(Combination of AI analysis + Human Interpretation)
  • Energy consumption distribution by TOU categories shows majority of the demand in Standard (57.2%), Off-Peak (25.0%), Peak (17.8%)
  • Consumption is quite low on Sundays and holidays, indicating that the factory is mostly closed on those days
  • Peak demand range: min = 2,507.974 kW; max = 30,066.219 kW; mean = 14,441.215 kW; std = 6,322.575 kW.
  • Monthly maximum peak values are tightly clustered: mean of monthly maxima = 28,855.67 kW, std ≈ 735 kW, indicating consistent high-load events each month
  • Highest Annual peak: 30,066.219 kW at 14 November 12:30 — ~2.02x the mean (30,066 / 14,441).
  • Top 25% of intervals have peak demand >= 20,051.816 kW (75th percentile).
  • Median peak demand is 12,383.057 kW, indicating a right-skewed distribution (mean > median).
  • Standard deviation (6,322.575 kW) shows substantial variability across 30-minute intervals—important for capacity planning and peak shaving strategies.
Let's further examine the Top 0.5% and 10% of the peaks by TOU category and the peaks for each month
The graph below shows the Top 90 (0.5%) demand intervals, color coded by Standard and Peak.
Insights
  • Highest-demand interval (rank 1, 30,066.22 kW) is a Standard rather than Peak. High-capacity intervals (top ranks) are often in Standard TOU windows, indicating high operational peaks can occur outside declared Peak windows.
  • Standard intervals dominate the dataset (≈57% of all intervals) and also dominate the top 10% subset (1,139 of 1,752 ≈ 65%) and 48% of the top 90 demand intervals.

  • If you are an manufacturing entity in Vietnam…
  • Do you have your 30 min load data? For how many years? Do you know where to get the data from, if you don't have it?
  • What is your consumption across TOU categories?
  • What does your LDC look like?
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Analysis of Monthly Demand Maxima
What are the monthly peak demand maxima and their characteristics?
Insights
  • The daily peak demand happens mostly in the afternoon (12:30 to 14:00) or a half-hour to an hour before the morning Peak (9:30 to 11:30).
  • TOU Category for monthly maxima: Peak in 9 of 12 months, Standard in remaining months
  • 11:00 is often the maximum peak period (see heatmaps below), and when the daily occurs in the middle of the night, it is only on Sundays (indicating the low usage of electricity on Sundays)
Let's further examine the timing of the peak demand by month and by day of the week.
Below are the AI Prompts, Execution Plan, and Progress Summary:
XanhTerra AI Prompt and Execution Plan for Heatmaps:
Visualization Results:

  • If you are an manufacturing entity in Vietnam…
  • Do you know when your factory has its daily maxima and why?
  • How do the maxima vary by month and by day of the week?
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Baseline vs. Trial Tariff Cost Comparisons
Now, let's calculate the monthly and annual costs under the Baseline and Trial tariffs.
XanhTerra's AI tool made the calculations, and the comparisons are show in the graph below. The full analysis summary from the Agentic AI tool is also provided below to highlight its capabilties.
(The left axis is for monthly costs in billions of VND and the right axis is for annual costs (the last columns) in billions of VND)
XanhTerra AI Analysis Summary:
Insights
(Combination of AI analysis + Human Interpretation)
  • Baseline average monthly total is 21.62 B VND (min 18.08, max 24.11), with an annual total cost of 259.41 B VND
  • Baseline energy cost is more sensitive to TOU energy volumes in Peak periods; months with higher peak kWh show larger Baseline totals (e.g., March).
  • EVN Trial average monthly total is 21.49 B VND (min 19.13, max 23.37), with an annual total cost of 257.83 B VND, a difference of only -0.6% annual.
  • Monthly capacity charges are stable in magnitude (mean 6.793 B VND/month) because monthly Pmax values vary within a limited range; capacity contributes ~30–35% of
  • Average monthly difference: -0.243 B VND (Trial tariffs slightly lower on average); however, the Trial tariff is higher in February, which had lower consumption than other months due to the Tet holidays.

It is likely that EVN and MOIT have attempted to make the difference between the Baseline and Trial tariffs relatively small.

  • If you are an manufacturing entity in Vietnam…
  • Do you already have estimates of how the Two-Component tariffs will impact your cost of electricity going forward?
  • What are you doing to reducing your peak demand periods?
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Comparison across Voltage Connection Levels
What if the factory was connected to 110 kV or 6 kV voltage level, instead of 22 kV?
Below is XanhTerra's AI Thought Process (including consulting a Financial Expert) and a draft Plan
Results:
Insights
  • Under Trial tariff, the factory would pay more only at the lowest-voltage case (Voltage below 6kV) by +2.40 B VND annually; all other voltage levels show annual savings under Trial (largest: -8.18 B VND at 6–22 kV).
  • The higher cost for the Voltage below 6kV is driven by high capacity charge, despite the energy-rate reductions.
  • Capacity charges constitute a material share of total Trial costs (approx 29%–35% depending on voltage).
  • Recommendation: Target peak reduction measures (demand response, load-shifting) to reduce monthly Pmax: each kW reduced lowers monthly capacity charge directly and materially reduces Trial total cost (capacity share ~30%+).
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Additional Questions…
Now that we know how the Trial tariffs may impact the monthly and annual consumption for a hypothetical manufacturing facility in Vietnam…
What more should factory owners consider about the new Trial Tariffs?

  • How would the changes in tariffs look like for a factory that operates 24/7?
  • How much savings would get from investing in reducing the peak capacity periods? Are investment costs in Energy Efficiency worth the savings?
  • What is the value of an un-dispatchable solar RTS to a factory, under the new tariffs?
  • By adding a BESS to the RTS, can the factory maximize its savings? What is the revised pay-back period for the BESS investment?
  • Would the factory save more under a DPPA? Should you partner with a solar or wind generator?
Want answers to these questions?
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