Thinking of investing in a grid-tie solar PV system?  Direct grid-tie PV systems will not produce power when the grid fails. For safety reasons, your home solar power system will automatically shut off if the power goes out. This is to protect utility workers who might be working on damaged or downed power lines during an outage from being exposed to live electricity.

So why not add batteries to your system?  Here’s why:

  1. Adding battery backup to your solar PV system can easily double the cost of your system.
  2. It  requires maintenance.
  3. The utility grid works fine 99% of the time, which is another reason why battery backup systems are not cost-effective.

When your system produces more electricity than you use – your electricity meter will run backwards and give you a full credit for the electricity you sent to the grid. When you need more electricity than your system is producing, you take it from the electricity supplied by the grid. Now your meter runs forward and first uses the credit that you accumulated earlier. This is called “net metering”.

Net energy metering is a special billing arrangement that provides credit to customers with solar PV systems for the full retail value of the electricity their system generates. Under net metering, the customer’s electric meter keeps track of how much electricity is consumed by the customer and how much excess electricity is generated by the system and sent back into the electric utility grid.