01Current TNB Medium Voltage Tariff Components
From 1 July 2025, TNB bills non-domestic Medium Voltage users under an unbundled schedule. Most Malaysian factories with demand above 1 MW are supplied at medium voltage, so the MV General tariff below is the starting point for most factory bills.
Under RP4, the bill is split into an energy charge per kWh, capacity and network charges per kW of Maximum Demand, and a fixed monthly retail charge. Understanding each component is critical to identifying where solar provides the greatest financial impact.
| Tariff Component | Rate | Description |
|---|---|---|
| Energy Charge | 29.83 sen/kWh | Charged on every kWh drawn from the grid |
| Capacity Charge (Generation) | RM29.43/kW | Charged on your monthly Maximum Demand (kW) |
| Network Charge (Transmission + Distribution) | RM59.84/kW | Charged on your monthly Maximum Demand (kW) — cables, substations, transformers |
| Retail Charge | RM200/month | Fixed monthly charge per account |
| AFA (October 2026) | +3.61 sen/kWh | Automatic Fuel Adjustment; set monthly |
| MD Charge Total (Capacity + Network) | RM89.27/kW | Combined charge on every kW of Maximum Demand |
Solar impact on unbundled tariffs: Onsite solar generation directly reduces the per-kWh Energy Charge and the fuel surcharge. The Capacity and Network Charges are billed per kW of Maximum Demand, so solar reduces them only when it lowers the peak recorded by the MD meter. The Retail Charge stays the same.
02TNB Medium Voltage & High Voltage Tariff Categories
Since 1 July 2025, TNB's non-domestic tariffs are structured by supply voltage and by whether you choose a General or Time of Use (ToU) rate. These categories replaced the old commercial (C1, C2) and industrial (E1, E2, E3) tariff names. Most Malaysian factories with demand between 1–10 MW are supplied at Medium Voltage (MV). Understanding which category you are on determines your MD charge exposure.
| Tariff | Typical User | MD Charge (RM/kW) | Energy / Peak (sen/kWh) | Off-Peak (sen/kWh) |
|---|---|---|---|---|
| MV General | Factories, cold storage and commercial buildings supplied at medium voltage | RM 89.27 | 29.83 sen | — |
| MV Time of Use | MV users who choose peak/off-peak pricing (MD charged on peak-period MD) | RM 97.06 | 31.32 sen | 27.23 |
| HV General | Large industrial sites supplied at high voltage | RM 31.21 | 43.03 sen | — |
| HV Time of Use | HV users who choose peak/off-peak pricing | RM 44.82 | 44.52 sen | 40.43 |
Critical: Medium Voltage users carry the heaviest MD charges — RM89.27/kW on MV General and RM97.06/kW on MV Time of Use, roughly three times the RM31.21/kW HV General rate. MV retail charge is RM200/month; HV is RM250/month. If your factory is supplied at medium voltage (most factories above 1MW demand are), Maximum Demand reduction is your single largest cost-reduction opportunity.
03Maximum Demand Explained: The RM89.27/kW Penalty
Maximum Demand (MD) is the single most misunderstood item on a Malaysian industrial electricity bill. It is not based on your total consumption — it is based on your peak consumption in any 30-minute window during the billing month.
How TNB Measures Maximum Demand
TNB installs a peak-demand meter that continuously samples your power draw. Every 30 minutes, it records the average kW consumption for that interval. The highest single 30-minute average across the entire month becomes your “Maximum Demand” — and you are billed at RM89.27 for every kW of that peak, for the entire month.
Common MD Spike Causes in Malaysian Factories
04What Solar Does to Maximum Demand: 500 kWp Example
A rooftop solar system's peak generation occurs between 10am and 2pm, when many Malaysian factories are busy. On a clear day the solar output lowers the grid draw, but MD is the highest 30-minute reading of the whole month: one cloudy half-hour during production can set the same MD as before. That is why Trexon's solar-only proposals count savings on energy and AFA only, and treat MD as unchanged.
Daily Load Profile: Solar on a Clear Day
Typical 500kW factory on the MV General tariff (8am–6pm operation)
Savings Calculation: 500 kWp Solar System
| Cost Component | Before Solar | After Solar | Monthly Saving |
|---|---|---|---|
| MD Charge (MV General, RM89.27/kW) | RM 44,635 | RM 44,635 | — (needs BESS) |
| Energy (29.83 sen × 105,000 kWh; solar displaces 52,500 kWh) | RM 31,322 | RM 15,661 | RM 15,661 |
| Retail Charge (MV) | RM 200 | RM 200 | — |
| AFA (October 2026: 3.61 sen) | RM 3,791 | RM 3,791 | — (AFA not counted) |
| Total Monthly Bill | RM 79,948 | RM 64,287 | RM 15,661 |
05Peak Shaving with Battery Storage (LFP BESS)
For factories where MD spikes occur outside solar hours — early morning shift start-ups, night shifts, or on overcast days — Lithium Iron Phosphate (LFP) Battery Energy Storage Systems can reduce MD when they are sized and operated for peak shaving; the result depends on your load profile and the battery size. Solar alone cannot do this reliably.
Solar-Only Peak Shaving
Cuts energy (kWh) charges during daylight hours, but does not reliably reduce MD: one cloudy half-hour during production sets the month's MD.
Solar + LFP Battery
Charges from solar during midday; discharges to shave peaks at any hour. Can reduce MD when sized and operated for peak shaving; results depend on your load profile.
| MD Reduction Target | BESS Power (kW) | BESS Capacity (kWh) | Cost | MD Savings/mo |
|---|---|---|---|---|
| 100 kW reduction | 100 kW | 200 kWh | Quoted per site | RM 8,927 |
| 200 kW reduction | 200 kW | 400 kWh | Quoted per site | RM 17,854 |
| 300 kW reduction | 300 kW | 600 kWh | Quoted per site | RM 26,781 |
| 500 kW reduction | 500 kW | 1,000 kWh | Quoted per site | RM 44,635 |
Run an MD savings estimate
Model the first-pass RM value of reducing your recorded maximum demand with BESS and solar.
Cold storage BESS
Peak-shaving and backup-cooling strategy for refrigerated warehouses and logistics sites.
Electronics BESS
Cleanroom, EMS and semiconductor load-profile strategy for MD control and resilience.
06AFA: A Variable Cost That Solar Avoids
Since July 2025 the Imbalance Cost Pass-Through (ICPT) has been replaced by the Automatic Fuel Adjustment (AFA), set monthly from fuel prices and exchange rates as determined by the Energy Commission. In October 2026 the AFA is +3.61 sen/kWh, adding RM3,610 per 100,000 kWh consumed.
| Period | AFA (sen/kWh) | Annualized Cost (per 1 GWh) |
|---|---|---|
| Sep 2026 | 3.67 sen | RM 36,700 |
| Oct 2026 ← Current | 3.61 sen | RM 36,100 |
| Nov 2026 (TNB forecast) | 4.27 sen | RM 42,700 |
| Dec 2026 (TNB forecast) | 4.46 sen | RM 44,600 |
| Jan 2027 (TNB forecast) | 7.59 sen | RM 75,900 |
Solar energy has no fuel cost. Every kWh generated by your rooftop solar system and used on site displaces one kWh from the grid at the full tariff rate including the AFA. As fuel prices and exchange rates move, the AFA moves with them; solar-displaced kWh become more valuable when the AFA rises.
“The MD charge is the silent killer of Malaysian factory profitability. Many factories we speak to have never analyzed their 30-minute demand profile. When you see the chart, it becomes clear which part of the bill solar can cut and which part needs a peak-shaving battery.”
07Frequently Asked Questions
What is TNB Maximum Demand (MD) and how is it calculated?
What is the TNB AFA and will it increase in future?
Does a 500 kWp solar system reduce my Maximum Demand?
What are the TNB Medium Voltage and High Voltage tariff categories?
Do I need battery storage (BESS) for peak shaving, or can solar alone do it?
Can I check my historical Maximum Demand data before commissioning solar?
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