1. Grid-Tied System:

This is the most popular PV installation system. It works as below:

• Any PV system produce energy when Sun is available.
• While designing PV system your day time and night time requirements are considered.
• This system is connected with your electric supplier / utility company.
• During day time, this PV system produce more energy than required in the day time. Additionally generated energy is sent to your utility co. They return your supply back to your home in the night time, when sun is not available and you are not producing energy.
• This is also called net-metering. In the end of month, utility company charge you for the net use of electricity only.

2. Battery-base or stand-alone System:

This system is popular where reaching to utility company is not possible like remote area, moving vehicle or when the customer do not want to remain connected to utility company. It works as below:

• This PV system also produce energy when Sun is available.
• While designing PV system your day time and night time requirements are considered.
• This system is not connected with your electric supplier / utility company.
• During day time this PV system produce more energy than required in the day time. Additionally generated energy is stored in battery.
  The stored power can be used at the night time, when sun is not available and you are not producing energy.
• As you are not connected to any utility company, you don't pay anything to utility co.