How to Calculate Electricity Cost for a Factory
By CalcNetra | Energy Cost Guide | Updated April 2026
Electricity is typically one of the top 3 operating costs for any industrial facility — yet most plant managers don't have a clear, step-by-step method to estimate or monitor it. This guide walks you through exactly how to calculate electricity cost for a factory, machine by machine or at the whole-plant level.
Step 1: The Basic Formula
The core calculation is straightforward:
To use this formula you need three values:
- Load in kW — the actual power consumption of your equipment
- Operating hours — how long it runs per day, month or year
- Electricity tariff — your utility's rate per kWh (found on your electricity bill)
Step 2: Find the Load (kW) of Your Equipment
Power consumption is listed on the equipment nameplate or in the technical manual. Common values for Indian factory equipment:
| Equipment | Typical Power (kW) | Monthly Cost (₹) at ₹8/kWh, single shift |
|---|---|---|
| Industrial motor (10 HP) | 7.5 kW | ~₹9,600 |
| Industrial motor (50 HP) | 37 kW | ~₹47,360 |
| Air compressor (25 HP) | 18.5 kW | ~₹23,680 |
| CNC machine | 5–25 kW | ₹6,400 – ₹32,000 |
| Injection moulding (150T) | ~22 kW | ~₹28,160 |
| Industrial furnace (small) | 50–200 kW | ₹64,000 – ₹2,56,000 |
| Factory lighting (per 1000 sq ft) | 2–5 kW (LED) | ₹2,560 – ₹6,400 |
If you only know the rating in HP, convert using:
The nameplate shows maximum load. Real-world consumption is typically 70–90% of nameplate depending on load factor. For accurate numbers, use a clamp meter or power analyzer on each machine. Use the HP to kW Converter for quick conversion.
Step 3: Estimate Operating Hours
How many hours does each machine run per month? Use this reference:
| Shift Pattern | Hours/Day | Days/Month | Hours/Month |
|---|---|---|---|
| Single shift | 8 | 25 | 200 hrs |
| Single shift (26 days) | 8 | 26 | 208 hrs |
| Double shift | 16 | 25 | 400 hrs |
| Double shift (26 days) | 16 | 26 | 416 hrs |
| Triple shift / continuous | 24 | 26 | 624 hrs |
Note: Not all machines run the entire shift. Factor in idle time, changeovers and maintenance stoppages for more accurate estimates. Use the Downtime Calculator to estimate actual running hours.
Step 4: Know Your Electricity Tariff Rate
Check your electricity bill for the energy charge per kWh. Indian industrial tariffs vary significantly by state and voltage category (HT vs LT):
| State | LT Industrial (₹/kWh) | HT Industrial (₹/kWh) | DISCOM |
|---|---|---|---|
| Maharashtra | ₹8.00 – ₹10.00 | ₹7.00 – ₹9.00 | MSEDCL / BEST |
| Gujarat | ₹6.50 – ₹8.50 | ₹6.00 – ₹7.50 | DGVCL / UGVCL / PGVCL |
| Tamil Nadu | ₹7.00 – ₹9.00 | ₹6.50 – ₹8.00 | TANGEDCO |
| Karnataka | ₹7.50 – ₹9.50 | ₹7.00 – ₹8.50 | BESCOM / HESCOM |
| Rajasthan | ₹6.50 – ₹8.50 | ₹6.00 – ₹7.50 | JVVNL / AVVNL |
| Uttar Pradesh | ₹6.50 – ₹8.00 | ₹6.00 – ₹7.00 | UPPCL / DISCOMs |
| Punjab | ₹7.00 – ₹8.50 | ₹6.50 – ₹7.50 | PSPCL |
| Telangana | ₹7.00 – ₹9.00 | ₹6.50 – ₹8.00 | TSNPDCL / TSSPDCL |
* Approximate ranges as of 2025–26. Always check your DISCOM's latest tariff order for current rates — tariffs are revised annually.
Your bill will also include fixed charges, demand charges, and power factor penalties — explained in the sections below.
Step 5: Full Worked Examples
Example 1 — Single Machine (CNC)
Monthly kWh = 15 × 200 = 3,000 kWh
Monthly Cost = 3,000 × ₹7 = ₹21,000/month | ₹2,52,000/year
Example 2 — Whole Plant
Shift: Double (16 hrs/day, 26 days = 416 hrs/month) | Tariff: ₹6.50/kWh
Monthly kWh = 175 × 416 = 72,800 kWh
Monthly Energy Cost = 72,800 × ₹6.50 = ₹4,73,200/month
Annual Energy Cost = ₹56.8 lakh/year (energy only, before demand charges)
Demand Charges — The Hidden Cost
Most industrial electricity bills include a demand charge — a fee based on your peak power demand (in kVA or kW) recorded during the billing month, not just total units consumed. This can add 20–40% to your total bill.
How Demand Charge is Calculated
How to Reduce Demand Charges
- Stagger machine startup times — large motors draw 5–7× nameplate current at startup, spiking your demand reading
- Use soft starters or VFDs — reduces startup current significantly
- Avoid running all heavy loads simultaneously — schedule large compressors, furnaces and motors in sequence
- Install a demand controller or energy management system — automatically sheds non-critical loads when demand approaches threshold
Power Factor Penalty
Poor power factor (below 0.90 or 0.95 depending on your DISCOM) means your plant is drawing more reactive power than it needs. Most Indian DISCOMs impose a penalty on low power factor — typically 1–2% additional charge for every 0.01 below the threshold.
Fix: Install capacitor banks to bring power factor to 0.95 or above. The investment typically pays back in 6–18 months. Use the Power Factor & Capacitor kVAR Calculator to find the right capacitor size for your plant.
Understanding Your Full Electricity Bill
Your total monthly electricity bill includes more than just energy units. Here's a typical Indian industrial bill breakdown:
| Bill Component | Based On | Typical Share of Bill |
|---|---|---|
| Energy Charges | kWh consumed × tariff rate | 55–70% |
| Demand / Fixed Charges | Peak kVA or kW recorded | 15–30% |
| Power Factor Penalty | PF below threshold (0.90–0.95) | 0–15% |
| Fuel Surcharge (FSA) | Fuel cost adjustment by DISCOM | 3–8% |
| Electricity Duty / Tax | % of energy charges (state-specific) | 5–10% |
| Meter Rent & Others | Fixed per month | 1–2% |
Understanding each component tells you exactly where to focus cost-reduction efforts. Energy charges respond to efficiency and VFDs. Demand charges respond to load scheduling. Power factor penalty responds to capacitor banks.
5 Proven Ways to Reduce Factory Electricity Cost
- Fix power factor with capacitor banks — eliminates PF penalty immediately and reduces kVA demand charges. Payback typically 6–18 months. → Calculate capacitor kVAR needed
- Install VFDs on pumps, fans and compressors — motors running at variable loads save 20–50% electricity. A pump running at 80% speed uses only 51% of its rated power (cube law). → Calculate current motor cost and potential savings
- Stagger machine startups — reduce peak demand spikes that drive demand charges. Schedule large motors with soft starters and avoid simultaneous starts.
- Upgrade to LED lighting — factory lighting can account for 10–15% of electricity use. LED upgrade saves 50–70% on lighting, with payback under 2 years in most cases.
- Improve OEE — more output with the same energy means lower electricity cost per unit produced. A factory improving OEE from 60% to 75% produces 25% more with the same electricity bill. → Calculate your OEE score
Calculate Your Factory's Electricity Cost Now
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