What is peak shaving with BESS?

Peak shaving uses a battery energy storage system to limit your maximum demand recorded by the utility meter. The EMS sets a kW threshold. When your facility load approaches that threshold, the BESS discharges to supply the difference. Your meter never sees more than the threshold, reducing your MDI (Maximum Demand Indicator) charge significantly.

How much can I save on my electricity bill with peak shaving?

A typical medium industrial facility in Karachi on B3 tariff with 500 kW sanctioned load can save Rs 3-4 million per year on MDI charges alone by controlling peak demand to 320 kW with a ZBox100-HS. Actual savings depend on your sanctioned load, tariff category and real peak demand profile.

Which NEPRA tariff categories benefit from peak shaving?

B2, B3 and B4 industrial consumers benefit most from peak shaving. These categories carry fixed demand charges based on the actual MDI or 25% of sanctioned load — whichever is higher. B3 has a minimum monthly charge of Rs 50,000 before any energy units. Peak shaving directly reduces the demand component of this bill.

Industrial Energy — Pakistan

Peak Shaving & MDI Charge Reduction Pakistan

Your electricity bill has two parts. Most factories only manage one. The MDI (Maximum Demand Indicator) charge — based on your single highest 30-minute demand in the month — can account for 30 to 50% of your total bill. Battery energy storage eliminates it.

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At a Glance

The MDI Problem — By the Numbers

30–50%

Of Your Bill

MDI fixed charges typically account for 30 to 50% of an industrial electricity bill in Pakistan — often more than the energy consumption charge itself.

30 min

Peak Window

NEPRA tariff bills you on your single highest 30-minute demand reading of the month. One bad day sets your charges for 30 days.

Rs 31–37

Per kWh 2025

Industrial tariff (B3) is running Rs 31–37/kWh in 2025 under the NEPRA uniform tariff, with additional QTA and FCA adjustments on top.

3–5 yr

Payback Period

A correctly sized BESS for peak shaving typically achieves payback in 3 to 5 years in Pakistan’s current tariff environment, with 15+ years of savings beyond that.

Understanding MDI

What Is an MDI Charge and Why Does It Cost You So Much?

MDI stands for Maximum Demand Indicator. Under Pakistan’s industrial tariff structure (NEPRA B2, B3, B4 categories), your electricity bill has two separate components: an energy charge per kWh consumed and a demand charge based on your peak kW demand measured over a 30-minute interval.

The demand charge is calculated on your highest single 30-minute reading of the entire billing month. If your factory runs a heavy startup cycle at 7am on one morning in the month, that spike sets your MDI for the full 30 days — even if every other hour was well within your normal operating range.

FESCO, LESCO, MEPCO, IESCO and K-Electric all apply this structure. Fixed charges are billed at a rate per kW per month based on 25% of sanctioned load or actual MDI — whichever is higher. For large B3 industrial consumers, the minimum monthly fixed charge alone is Rs 50,000, before any energy units are consumed.

How It Works

How BESS Eliminates Your MDI Charge

Peak shaving with a battery energy storage system is straightforward in principle. The engineering is in the sizing and the EMS configuration.

Step 1

Set a Demand Threshold

Your EMS is configured with a maximum kW threshold — say, 400 kW on a 500 kW sanctioned load. This becomes the ceiling your meter is never allowed to exceed.

Step 2

Battery Kicks In at the Threshold

When your facility load approaches 400 kW, the BESS automatically discharges to supply the difference. The grid meter never sees more than the threshold. The 30-minute peak reading stays flat.

Step 3

Recharge During Off-Peak Hours

The BESS recharges from the grid during overnight off-peak hours when energy tariff rates are lowest. The cycle repeats every day, automatically, without operator intervention.

Result

MDI Drops to Threshold Level

Your MDI charge is now based on your controlled threshold, not your real peak. On a 500 kW sanctioned load, this can eliminate 20 to 35% of your monthly bill immediately.

Bonus

Backup During Load Shedding

The same BESS provides backup power during K-Electric or WAPDA outages. Production continues. Startup costs, scrap losses and worker downtime are eliminated simultaneously.

Optional

Solar Integration

Pair BESS with rooftop solar to reduce your daytime energy consumption charge as well. The BESS stores excess solar generation for discharge during evening peak hours.

Worked Example

What Does Peak Shaving Actually Save a Karachi Factory?

A medium industrial facility in Karachi on K-Electric B3 tariff with 500 kW sanctioned load and a real peak demand of 480 kW:

Without BESS

Full MDI Exposure

MDI = 480 kW
Fixed charge rate ≈ Rs 1,800/kW/month
Monthly MDI charge ≈ Rs 864,000
Annual MDI cost ≈ Rs 10.4 million

With BESS Peak Shaving

Controlled at 320 kW

MDI = 320 kW (threshold set)
Fixed charge rate ≈ Rs 1,800/kW/month
Monthly MDI charge ≈ Rs 576,000
Annual MDI cost ≈ Rs 6.9 million

Annual Saving

Rs 3.5 Million / Year

MDI saving alone
Additional saving from solar integration possible
ZBox100-HS payback ≈ 4 years
15+ years of savings beyond payback

* Illustrative example based on indicative B3 tariff rates. Actual savings depend on your load profile, tariff category and sanctioned load. We model your actual data before recommending any system.

Our Products for Peak Shaving

The Right BESS for Your Load

Every peak shaving system is sized from your actual 15-minute interval demand data. The product recommendation follows the analysis.

Zetara ZBox60

61.44 kWh — Small C&I

For smaller commercial and light industrial sites. Entry-level peak shaving and backup. 614.4V DC, IP20, modular rack.

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Zetara ZBox100-HS peak shaving BESS Pakistan

Zetara ZBox100-HS — Most Specified

102.4 kWh — Medium Industrial

50 kW rated. 4-MPPT hybrid inverter. HVAC cooling. Factory acceptance tested. The most common choice for Karachi and Lahore industrial sites.

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Zetara ZBox200

215 kWh — Large Industrial

For large factories, multi-shift operations and high-demand industrial sites. Containerised, IP55, integrated fire suppression.

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Our Process

How We Size Every Peak Shaving System

We do not recommend a product size based on your sanctioned load. We model your actual demand data before any system is specified.

01 12 months of utility bills — we extract your monthly MDI peaks, energy consumption and tariff category to establish the baseline we are working to reduce.
02 15-minute interval data — where available, we use sub-hourly demand data to identify the exact shape of your peak. This determines the optimal BESS power and energy sizing.
03 Financial model — we calculate MDI saving, energy arbitrage value and backup value. We show you payback period, IRR and 10-year NPV before you commit to anything.
04 System specification — product selected, SLD designed, NEPRA/DISCO grid connection requirements addressed. EMS configured to your specific tariff schedule.
05 Factory acceptance test & commissioning — system arrives pre-tested with EMS loaded. On-site commissioning confirms all parameters. Handover documentation issued.

Get Started

Get Your Free Peak Shaving Assessment

Send us your last 12 months of utility bills and we will model your MDI saving, size the right BESS and show you the financial case — before any commitment is made.

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