Maximum Demand Charge: How RP4 Splits Your Bill

What is a maximum demand charge?

A maximum demand charge is the part of a commercial or industrial electricity bill based on your highest rate of power draw in a month — measured in kilowatts (kW) — not on the total energy you consume (kWh). It is billed on a single number: the worst half-hour of the month. Run every machine you own at once for thirty minutes, and that peak sets a charge you pay against for the whole billing period, even if the rest of the month was quiet.

For a medium-voltage site in Malaysia, the maximum demand charge is often the largest controllable line on the bill. Under the RP4 tariff that took effect on 1 July 2025, the way it is calculated changed in a way every operator should understand — the old single MD charge was split into two separate charges. This guide explains what maximum demand is, how RP4 unbundled it into a Capacity Charge and a Network Charge, what the exact rates are, and how to bring the number down.

How maximum demand is measured

Maximum demand is not your average load. It is the highest average power over a short interval — in Malaysia, a 30-minute window — recorded at any point during the billing month.

The meter continuously averages your power draw across each half-hour. At the end of the month, the single highest of those half-hourly averages becomes your maximum demand, and that one figure is what you are billed on. Two consequences follow:

- It's about coincidence, not size. A facility's MD is driven by how many large loads happen to run at the same time, not by how big any single machine is. Three chillers that never stage together produce a lower peak than two that always start in unison.
- One bad half-hour costs all month. A single coincident spike — a shift start, a batch of motors energising together, a chiller and a compressor overlapping — can set a peak you then pay against for thirty days. We walk through reading your own peak correctly in how to calculate maximum demand.

How RP4 changed the maximum demand charge

Before RP4, TNB billed a single Maximum Demand charge in RM per kW against your monthly peak. From 1 July 2025, under the RP4 regulatory period (2025–2027), that single charge was unbundled into two separate per-kW charges: a Capacity Charge and a Network Charge. Both are still billed against the same monthly maximum demand figure — the change is in how the cost is broken out and what each part pays for.

The bill as a whole now has more visible components: an Energy Charge (sen/kWh), the Capacity Charge (RM/kW), the Network Charge (RM/kW), a Retail Charge, and the Automatic Fuel Adjustment (AFA), which replaced the older ICPT mechanism. The two we care about here — Capacity and Network — are the ones driven by your peak demand.

What the Capacity Charge pays for

The Capacity Charge reflects the cost of having enough generation capacity available to meet your demand when you call on it. You are paying for the power stations and reserve margin that have to exist so the grid can serve your peak, whether or not you draw it often. It is billed per kW of your maximum demand.

What the Network Charge pays for

The Network Charge reflects the cost of the transmission and distribution network — the lines, substations and transformers — sized to deliver your peak power to your door. The bigger your peak, the more grid infrastructure has to be reserved for you, so this too is billed per kW of maximum demand. On most medium-voltage tariffs the Network Charge is the larger of the two.

The logic of the split is that your peak demand drives two different costs — the capacity to generate and the network to deliver — and RP4 now prices them separately. For you as the operator, the practical takeaway is unchanged and amplified: every kW you shave off your peak now reduces two charges at once.

RP4 maximum demand rates by tariff (2025–2027)

Here are the combined Capacity + Network charges per kW of maximum demand for the medium-voltage tariffs most commercial and industrial sites use, effective 1 July 2025:

- C1 (commercial, general MV): RM89.27/kW — Capacity RM29.43 + Network RM59.84
- C2 (commercial, ToU MV): RM97.06/kW — Capacity RM30.19 + Network RM66.87
- E1 (industrial, general MV): RM89.27/kW — Capacity RM29.43 + Network RM59.84
- E2 (industrial, ToU MV): RM97.06/kW — Capacity RM30.19 + Network RM66.87
- E3 (industrial, high-voltage ToU): RM44.82/kW — Capacity RM21.76 + Network RM23.06

These are the demand-related charges only; energy (sen/kWh), retail and AFA are billed separately. Always confirm the current rates for your exact tariff against TNB's official tariff schedule, as the Energy Commission can revise them within the RP4 period.

Worked example: what your peak actually costs

Put real numbers on it. Take a medium-voltage commercial site on the C2 tariff with a monthly maximum demand of 1,000 kW:

- Capacity Charge: 1,000 kW × RM30.19 = RM30,190/month
- Network Charge: 1,000 kW × RM66.87 = RM66,870/month
- Combined demand charge: 1,000 kW × RM97.06 = RM97,060/month

That is roughly RM1.16 million a year in demand charges alone, before a single kWh of energy is counted.

Now shave the peak. If staggering equipment and trimming coincident loads cuts the monthly maximum demand by 100 kW, you save 100 × RM97.06 = RM9,706 every month — about RM116,000 a year — without producing one unit less or installing any generation. That is the financial case for maximum demand management in one line.

Why the Time-of-Use window matters under RP4

For the ToU tariffs (C2, E2, E3), when you draw power also shapes the energy portion of your bill, and the RP4 window changed. The peak period is now 2:00pm to 10:00pm on weekdays; off-peak is 10:00pm to 2:00pm on weekdays, plus all day on weekends and public holidays.

Shifting deferrable load — battery charging, non-urgent process runs, pre-cooling — out of the 2pm–10pm window lowers your energy cost on a ToU tariff. It does not, on its own, change your maximum demand charge, which is set by your single highest half-hour whenever it occurs. The two levers are related but distinct: manage coincident peak to cut the demand charge, and manage timing to cut the ToU energy charge. The biggest savings come from doing both.

How to reduce your maximum demand charge

Bringing the peak down is an operational and data problem, not a hardware one. The proven levers:

1. See the peak as it forms. You cannot manage a number you only meet on a monthly bill. Real-time maximum-demand tracking shows the peak building so you can act inside the half-hour that matters.
2. Stagger large starts. Sequence chillers, compressors and big motors so they don't energise together. Most peaks are coincidence, and coincidence is schedulable.
3. Shed or shift flexible load. Move deferrable loads off the peak and trim non-essential equipment when demand approaches your target ceiling.
4. Set a demand target and defend it. Treat a kW ceiling as an operational limit, with alerts before you breach it.

We go deeper on the tactics in cutting TNB maximum demand charges. The common thread is visibility: every one of these levers depends on seeing equipment-level demand in real time.

Where monitoring turns the bill into a target

This is the job a Smart Operation Platform does that a meter and a monthly bill cannot. CobiNeural tracks the Maximum Demand KPI live — across the site and down to individual equipment — so you can see which loads are building the peak, get alerted before you breach a target, and stagger or shed before the half-hour closes. Its Billing & Tariffs module models the RP4 components and allocates cost across tenants or cost centres, so the bill becomes a number you manage rather than one you receive.

The same demand data does double duty for compliance: it is exactly what an EECA energy management programme needs to document, so a demand-reduction measure is both a lower bill and audit evidence. For operators running several buildings, multi-site energy management puts every site's peak on one screen so you can attack the demand charges that cost the most first.

Maximum demand is the most controllable large charge on a Malaysian commercial or industrial bill, and RP4 made it more transparent, not more forgiving. To see your own peak forming in real time and model what shaving it is worth, book a CobiNeural walkthrough.

Sources

- Understand Your Electricity Tariff — TNB Malaysia
- July 2025 TNB tariff update — Plus Xnergy