Comparing Direct Grid-Tie With Battery Based Home Solar System

Solar power installation at home can either be directly tied to the power grid or it can be independent of the power grid. Both systems have their own merits and demerits.

Solar installation connected to the power grid is easy to install and the system ensures uninterrupted supply of power to the home. If the power supply from the power grid is unreliable, the home owner can use back up batteries or portable generators.

A solar installation not tied up with the power grid has to use electrical appliances of 24 volts DC. Though this system is ideal for places where mains electrical transmission lines are not there, it cannot serve all household purposes. However, a power inverter can convert the DC power stored in the battery to AC power.

Tying Up Solar Installation With The Power Grid

This is the easiest solar system to install since the system needs only the solar panels, an inverter and a switch. The inverter is connected to the power grid’s supply line through the switch.

When the solar system produces more energy than the needs of the home, the excess energy is transmitted to the power grid. When electricity passes on to the power grid’s power pool, the electric meter spins in the reverse order. The reverse spinning of the electric meter quantifies the power supplied to the power grid and the home owner is paid for the power according to the reading on the electric meter.

The meter has to be the one installed by the power grid because all meters cannot record the amount of power supplied to the power grid by spinning backwards. Having your solar installation tied up with the power grid offers other advantages also. Since there is an inverter, you can use home electrical appliances which work on AC.

All your home electricity needs will be met by the energy produced by your solar installation. Since batteries are not needed, your installation cost will be less. The system doesn’t need repairs often.

An advanced technology uses micro inverters where each solar panel is connected to separate inverters. The advantage of this technology is that even if one solar panel fails to produce energy, the other panels will continue to produce power and your house will have an uninterrupted supply of power.

Off Grid Solar Energy Installation

If the solar installation is not tied up with the power grid, the system has to have batteries to store the excess energy produced. Adding batteries to the system complicates the system and there will be recurring maintenance costs.

The inverter has to be a special one, capable of converting DC to AC and automatically switching on to DC if AC fails. The batteries will cost an addition amount of 4 to 5 thousand dollars. You also have to have separate wiring for appliances which work on DC.

A battery based solar installation needs to have other back up power production devices like a gas or diesel generator because the solar power produced during bad weather conditions will not be sufficient to meet the energy needs of the house.

The only plus point for a battery based solar installation is that the inverter doesn’t have to be connected to the supply lines of power grid and there is no need for the switch to shut off power supply to the power grid.