Peak Shaving for Business:
How to cut peak load and save 40%

For most industrial enterprises in Ukraine, 30-50% of the electricity bill is paid for peak power. BESS allows you to automatically cut these peaks, reducing bills by hundreds of thousands of hryvnias every month. In this article, we will consider how peak shaving works, real calculations for a plant with a peak load of 500 kW and why the payback is only 2-3 years.

What is the fee for peak power in Ukraine

The tariff structure for industrial consumers in Ukraine consists of two key components: payment for consumed electricity (kWh) and payment for maximum capacity (kW). The second component is called a demand charge, or a fee for peak load.

Oblenergo records the maximum 15-minute or 30-minute consumption during the billing period. Even if the peak was only 20 minutes a month, you pay for it for the whole month. For enterprises with an uneven load schedule (production of powerful machines, compressors, electric furnaces), this means that short-term peaks can increase the bill by 200-400 thousand UAH/month.

How BESS automatically cuts peaks

The Peak Shaving system based on BESS works according to a simple but effective algorithm. The EMS (Energy Management System) controller constantly monitors the enterprise's consumption in real time. When the load approaches a set threshold (for example, 350 kW at a contracted capacity of 500 kW), the BESS begins to discharge, compensating for the difference.

Load profile: before and after BESS

Below is a typical daily load profile of a metalworking plant (Kyiv region). The red dashed line is the peak power threshold of 500 kW. The green dashed line is the effective threshold after peak shaving (350 kW). The 500 kWh / 250 kW BESS cuts all peaks above the threshold.

Actual calculation: Plant 500 kW

Consider the case of a metalworking enterprise with a peak load of 500 kW. The average load is 280 kW, but 2-3 times a day when the CNC machines, compressors and electric furnace are started simultaneously, the consumption jumps to 480-520 kW for 15-30 minutes.

Monthly electricity bill (thousand UAH)

* Additional energy savings due to charging BESS in off-peak hours at a lower rate (tariff arbitrage)

Additional bonus: tariff arbitration

BESS for peak shaving works only 2-4 hours a day in discharge mode. The rest of the time the battery can be used for tariff arbitration — charging at night (tariff 1.68 UAH/kW*h) and discharge during the day (tariff 4.2 UAH/kW*h). This adds another 15-20% savings to the basic peak shaving.

"We installed BESS 300 kWh for peak shaving at our plant. In the first month, we saved 68,000 UAH only on the payment for capacity. Plus 22,000 UAH on arbitration. Full payback — less than 2.5 years." — Director of metalworking plant, Kyiv region.

How to determine the optimal size of BESS

The size of a BESS system for peak shaving depends on three factors: the peak amplitude (the difference between the average and maximum load), the duration of the peaks, and the frequency of their occurrence. Formula for preliminary assessment:

Calculation example

For our plant: (500 - 300) x 0.5 h x 3 times x 1.25 = 375 kW*h. We choose the nearest standard size — 500 kWh (one CATL EnerOne container), which gives an additional margin for tariff arbitrage.

ROI and financial model

Technical requirements for the peak shaving system

Not every BESS is suitable for peak shaving. Key features:

• C-rate minimum 0.5C: The battery must deliver power quickly enough. For 500 kWh, this means a minimum of 250 kW output power.
• Response time <200 ms: Peaks last for minutes, so the system must respond instantly.
• Cyclic resource 6000+: Peak shaving involves 1-3 cycles per day, i.e. 365-1095 cycles per year. LiFePO4 with a resource of 6000 cycles provides 6-15 years of service.
• EMS of predictive algorithm: The controller must not just react to the peak, but predict it based on consumption patterns.
• Integration of ASKOE: Connection to an automated commercial electricity metering system for accurate metering.

Frequently Asked Questions

Is it necessary to change the contract of oblenergo after installing BESS?

Yes, and this is a positive point. After confirming the effectiveness of peak shaving (usually 2-3 months of work), you submit an application to reduce the contracted capacity. For example, of 500 kW to 320 kW. This legally reduces your power rate. The procedure takes 1-2 months.

Does peak shaving work at the same time as backup power?

Yes. Modern EMS support multimode. In normal mode, BESS performs peak shaving and tariff arbitration. When the network is disconnected, the system automatically switches to UPS mode (uninterruptible power supply), providing critical load. It is recommended to reserve 20-30% of the capacity for an emergency reserve.

What is the minimum enterprise size for peak shaving?

Economic feasibility begins with a peak load of 100 kW and a difference between peak and average load of at least 30-40%. For enterprises with an even schedule (for example, round-the-clock production without start-up loads), peak shaving is less effective. Minimum CAPEX — from $15,000 for a 100 kWh system.

How quickly does BESS respond to a load spike?

The response time of modern BESSs based on LiFePO4 is 50-200 ms from detection to full power. It is much faster than any mechanical solutions. EMS constantly analyzes the load curve and starts pre-discharge even before the threshold is reached if the algorithm predicts a peak.

Does peak shaving affect the quality of electricity?

Positively. BESS smooths out not only power peaks, but also voltage spikes that often occur when starting large electric motors. The BESS inverter can compensate for reactive power (cos φ correction), which further reduces losses and improves network quality in the enterprise.

How many years will BESS for peak shaving last?

With a typical mode of 1-2 cycles per day, a LiFePO4 battery (6000-8000 cycles at DOD 80%) will last 10-15 years. Capacity degradation — 2-3% per year. After 10 years, the remaining capacity will be 70-80%, which is still enough for effective peak shaving. Manufacturer's warranty (CATL, BYD) — 10 years or 6000 cycles.