Reactive Power and Power Factor — How Solar Affects Your Meralco Bill

Most residential Meralco customers pay only for active power (kWh). But commercial and industrial accounts also pay for reactive power (kVAR) through power factor charges. Understanding how solar inverters interact with power factor is important for commercial solar customers.

Active Power vs Reactive Power

Active power (kW): Real work — powers lights, motors, computers. You pay per kWh.

Reactive power (kVAR): Magnetic field energy in motors and transformers — no useful work but flows through wires. Poor power factor means paying for losses.

Power factor (PF): kW ÷ kVA. Perfect PF = 1.0. Typical commercial building: 0.80-0.90. Meralco penalizes PF below 0.85 for commercial accounts.

How Solar Inverters Handle Power Factor

Power Factor Correction for Commercial Solar

If your commercial building has a low power factor (below 0.85), your Meralco bill includes a kVAR surcharge. Two solutions work together:

• Capacitor banks: Traditional PF correction — ₱50,000–200,000 for commercial systems
• Smart solar inverter: Some hybrid inverters can supply reactive power compensation — check with your installer if your inverter supports this feature

Checking Your Meralco Bill for Power Factor Charges

On your Meralco commercial bill, look for:

• "Reactive Energy Charge" or "kVAR charge" line item
• Your recorded power factor (should be listed on the bill)
• If PF is below 0.85 and you're paying a reactive charge, PF correction is worthwhile

A 100kW commercial solar system with reactive power compensation mode can eliminate ₱15,000-40,000/month in kVAR charges in addition to energy savings.

Find commercial solar specialists at solarenergyph.shop.

Engr. Jason Morales — Founder, SolarEnergyPH