What Is MDI in Your Electricity Bill (and How Solar Helps Reduce It)

This guide explains what MDI means, how MDI charges are calculated on Pakistani industrial tariffs, and what solar panels, batteries and better load management can and cannot do about it.

MDI stands for Maximum Demand Indicator

Your electricity bill normally has two kinds of charges:

• Energy charges (variable): what you pay for units consumed, measured in kWh.
• Fixed charges: what you pay for the capacity the grid must keep ready for you, measured in kW.

The kWh reading tells the electricity company how much energy you used over the month. The MDI reading tells it the highest rate at which you drew power. A meter usually averages demand over a short window (commonly 30 minutes) and keeps the highest average it sees. That number appears on your bill as MDI.

A simple way to picture it: kWh is the total distance you drove this month; MDI is your top speed.

Diagram

How MDI turns into a fixed charge

• MDIMeter records your highest demand (kW) in a billing month
• BILLED kWHigher of MDI or a share of sanctioned load
• × RATEe.g. B-3: Rs 1,250 per kW per month (Feb 2026)
• CUT ITSolar and BESS trim daytime peaks; shift heavy loads

Current rates (February 2026 tariff decision): the B-3 (11–33 kV industrial) fixed charge stays at Rs 1,250 per kW per month. Domestic fixed charges now run from about Rs 200 to Rs 675 per kW per month depending on the consumption slab. B-2 rates are on your own bill; check the fixed charge line.

Which consumers pay MDI-based charges?

MDI matters mainly for consumers whose tariff includes a fixed charge per kW per month. In Pakistan that typically includes:

Category boundaries and rates are set by NEPRA and notified by the government; check your distribution company's current tariff page.

Recent tariff schedules published by Punjab distribution companies (for example IESCO's 2026 tariff guide) list the B-2, B-3 and B-4 fixed charge as a rate per kW per month. Read your bill for the exact category printed on it.

How MDI charges are calculated

Tariff notes published by distribution companies state that, where fixed charges are per kW per month, they are billed on a percentage of sanctioned load or the actual MDI for the month, whichever is higher. FESCO's tariff page and a 2026 NEPRA complaint decision involving LESCO both refer to 25% of sanctioned load. Some reporting on the 2026 tariff changes refers to 50% for certain time-of-use consumers.

Here is what that rule means in practice.

Example arithmetic (illustrative numbers only, not current tariff rates):

• Sanctioned load: 200 kW
• Floor at 25% of sanctioned load: 50 kW
• Actual MDI recorded this month: 140 kW
• Billable demand: the higher of 50 kW and 140 kW = 140 kW
• If the fixed charge were Rs 1,000 per kW per month, the fixed charge would be 140 x 1,000 = Rs 140,000.

Now suppose the same factory had kept its peak at 110 kW instead:

• Billable demand: 110 kW
• Fixed charge at the same illustrative rate: Rs 110,000

The 30 kW difference in peak changes the fixed charge, even if the total units consumed stay similar. Use your own bill's tariff rate to repeat this calculation.

Two important points follow from the rule:

1. Lowering MDI only helps down to the floor. Once your MDI is below the percentage of sanctioned load, the floor applies and further reductions do not change the fixed charge.
2. One spike sets the month. A few minutes of high demand, such as several large motors starting together, can set the MDI for the whole billing period.

What causes a high MDI reading?

• Several heavy machines, compressors or chillers starting at the same time
• Shift changes when all lines restart together
• Air conditioning and process loads peaking together on hot afternoons
• Switching from generator back to grid with all loads connected
• Grid restoration after load-shedding, when everything comes back on at once
• Faulty meters or billing errors (NEPRA has handled complaints where an accumulated MDI was billed in a single month)

If an MDI reading looks wrong, compare it with your connected load and previous bills, and raise it with your distribution company. Consumers can escalate unresolved billing complaints to NEPRA.

Does solar reduce MDI?

Sometimes, but not on its own. This is where many factory owners are disappointed, so it is worth being clear.

Solar panels reduce the power you draw from the grid while the sun is shining. MDI, however, records your single highest demand at any time in the month. If your peak happens:

• In the evening or at night, solar produces nothing and the MDI stays the same.
• On a cloudy or smoggy day, solar output drops and the grid supplies the peak.
• During a brief cloud passing over the plant, output can fall within minutes, and the demand jumps back to the grid.

So a solar system can cut your energy (kWh) charges a great deal while leaving your MDI almost unchanged. Any MDI reduction from solar alone depends on your load timing and is not guaranteed.

When solar can help with MDI

• Your peak is consistently in the middle of the day, when solar output is high.
• The solar plant is large compared with your daytime load.
• The system is combined with storage or controls designed for peak reduction.

Ways to reduce MDI charges

1. Stagger heavy loads

Start large motors, compressors and chillers one at a time rather than all together. This costs nothing and is often the first step.

2. Use soft starters or VFDs on large motors

These reduce the starting surge of motors. A qualified electrical engineer should assess which motors are worth changing.

3. Review your sanctioned load

If your sanctioned load is far higher than you ever use, the floor may be setting your fixed charge. Changing sanctioned load involves an application to your distribution company and may have its own costs and conditions.

4. Add battery storage for peak shaving

A battery energy storage system (BESS) can discharge at the moment demand rises, so the grid sees a lower peak. This is called peak shaving. It works only if the battery and controls are sized and programmed for your actual load profile. Our BESS for factories guide explains when this makes sense. We design BESS solutions using equipment from Huawei, Sungrow and Luminey.

5. Design solar and controls together

For industrial sites, solar, grid, generator and battery can be designed as one hybrid system with an energy management controller. The aim is to meet the daytime load from solar, cover short dips with the battery and keep grid demand below a set level.

How Solar Works Pakistan approaches MDI in industrial projects

Solar Works Pakistan is a solar EPC, engineering and trading company headquartered in Faisalabad, with specialist focus on industrial EPC, hybrid systems and BESS. We have served 50+ industrial clients, including textile, dyeing and loom units.

For an industrial site, our engineers start with:

1. 12 months of electricity bills, showing kWh, MDI and tariff category
2. Load analysis of major machines and their running schedule
3. Site survey of roof, sheds and electrical rooms
4. A design that separates what solar can do for energy costs from what storage or load management can do for MDI

We will not promise an MDI reduction we cannot engineer. If solar alone will not change your peak, we will tell you, and explain what would. Read more on our industrial and commercial solar page and our guide to solar for Faisalabad textile, dyeing and loom units.

Get today's price or a free site survey

Send us your last 12 months of bills and we will review your MDI pattern as part of the survey.

• WhatsApp or call: 0336 666 4321
• Email: info@solarworks.pk
• Head office: Main Boulevard, Sargodha Rd, Block F FDA City, Faisalabad
• Lahore branch: 2nd Floor, Jeff Heights, Gulberg, Lahore
• Hours: 9:00 AM to 6:00 PM, daily
• We serve industrial, commercial and residential customers throughout Punjab. Contact us.

Frequently asked questions

What does MDI stand for in an electricity bill?

MDI stands for Maximum Demand Indicator. It shows the highest demand in kilowatts that your meter recorded during the billing period, usually averaged over a short interval.

What are MDI charges?

MDI charges are the fixed charges on your bill that are calculated per kW of demand. Where the tariff charges per kW per month, the billable kW is generally your actual MDI or a set percentage of your sanctioned load, whichever is higher.

Is MDI the same as units consumed?

No. Units (kWh) measure total energy used over the month. MDI (kW) measures the highest rate of use at any point. A factory can use fewer units and still have a high MDI if loads start together.

Will installing solar panels lower my MDI?

Not necessarily. Solar lowers grid demand only while it is producing. If your peak happens in the evening, at night or during cloudy weather, MDI may stay the same. Storage or load scheduling is usually needed to reduce MDI reliably.

Can a battery reduce MDI charges?

Yes, if it is designed for peak shaving. The battery discharges when demand rises so that grid demand stays below a target. It must be sized to your actual load profile and controlled automatically.

Why is my MDI higher than my running load?

Starting surges, several machines starting together, return of supply after load-shedding, or a meter or billing error can all cause it. Compare with past bills, and raise unusual readings with your distribution company.

Does net metering or net billing remove MDI charges?

No. MDI-based fixed charges are separate from how exported units are credited. See our net metering and net billing guide for current export rules.

Sources

1. IESCO, Tariff guide (2026 schedule)
2. FESCO, Electricity tariff page
3. NEPRA, complaint decision involving LESCO and MDI billing (August 2026)
4. The News, report on the 2026 tariff changes and fixed charges (February 2026)
5. Profit (Pakistan Today), report on NEPRA and industrial fixed charges (February 2023)
6. The Friday Times, article on MDI-based fixed charges (July 2024)