On-Grid (Net Metering) Inverters — Pakistan Guide

On-grid inverters shut down during outages for safety. Use hybrid/off-grid for backup. This is a safety feature called anti-islanding protection, which prevents the inverter from feeding power back into the grid during an outage when utility workers might be working on the lines.

If you need backup power during outages, consider a hybrid inverter system that can switch to battery power when the grid fails, or install a separate off-grid/UPS system for essential loads.

Credits depend on NEPRA rules and your DISCO; confirm current rates. In Pakistan, net metering tariffs vary by DISCO and are typically lower than the import rate. For example:

• You might pay PKR 20 per unit for electricity imported from the grid
• But receive only PKR 12-15 per unit for electricity exported to the grid
• The difference between these rates affects your overall savings

Always check the current net metering tariff structure with your local DISCO before installing a system, as these rates can change based on NEPRA regulations.

No—on-grid does not require batteries. One of the main advantages of on-grid systems is their simplicity and lower cost compared to hybrid or off-grid systems, primarily because they don't need battery storage.

However, there are some considerations:

• Without batteries, you have no backup power during grid outages
• All excess energy is exported to the grid (no nighttime self-consumption)
• System maintenance is simpler and less expensive

If you want both net metering benefits and backup power, a hybrid system would be more appropriate, though it comes at a higher initial cost.

The size of your on-grid inverter should be based on your electricity consumption and available roof space. Here's how to determine the right size:

• Review your last 12 months of electricity bills to find average monthly consumption
• Divide monthly consumption by 30 to get daily average in kWh
• Multiply daily consumption by 1.2 to account for system losses
• Divide by 4-5 hours of average daily sunlight in Pakistan

For example, if your monthly consumption is 600 units (kWh), your daily average is 20 kWh. With the calculation above, you'd need approximately a 5kW system. Always consult with a professional installer for accurate sizing.

The net metering approval process in Pakistan typically takes 2-4 weeks from application submission to final approval, though this can vary by DISCO and location. The process involves:

• Application submission with required documents
• Technical review of your proposed system
• Site survey (sometimes required)
• Approval and agreement signing
• Net meter installation

Starting the approval process before or simultaneously with your solar system installation can help reduce overall timeline. Some DISCOs may have longer processing times during peak periods.

Yes, it's possible to upgrade from on-grid to hybrid, but there are important considerations:

• Your existing on-grid inverter may need to be replaced with a hybrid model
• You'll need to add a battery bank and charge controller
• Additional wiring and safety components will be required
• You may need to reapply for permits or modify your net metering agreement

While possible, it's often more cost-effective to install a hybrid system from the beginning if you anticipate needing battery backup in the future. However, if budget constraints require starting with on-grid, plan your system with future hybrid conversion in mind.