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How solar connects to the grid

Solar on rooftops is now one of the biggest sources of power to the grid. But have you wondered how it  gets from your roof to the network?

Nearly one in three WA homes have solar on their rooftop and it’s pretty much a standard inclusion for most builders and developers these days.

A residential solar system is owned by the property owner (except in cases where it might be managed by a strata or body corporate).

However for solar panels to be effective, and for the home to get consistent and stable power, the solar system needs to be connected to the grid. This is so the property can be supplied with grid power when the sun is not shining and the panels are not generating, and to export power when the panels are generating more energy than the property requires.  

Solar panels being installed on a roof

So how does solar connect to the grid?

A solar power system, which needs to be installed by a qualified solar installer and approved by Western Power, is made up of several key parts, including the panels and an inverter.

The inverter is the critical and hard-working key to making your solar set-up work.

It transforms the power generated by your solar panels from DC to the AC frequency used by your home and the grid.

DC is direct current which means the flow of charge (power) moves steadily in one direction, whereas AC is alternating current where it switches back and forth. So a solar inverter converts DC to AC so it is suitable for use in your home.

It also acts as the connector between your panels and the grid, so power can be exported into the network.

The maximum capacity on the also determines how much solar you can generate, no matter the number of panels on the roof.

There are different types of inverters – all serve their purpose but they must meet Australian Standard (AS) 4777.

Rooftop solar panels being connected up by an solar installer

Typically, the inverter is positioned somewhere outside the house on a wall. As the sun rises and the solar panels start to catch rays, the inverter ‘wakes up’. The first thing it does is connect to the grid, to let it know there might be solar activity coming and ensure the network is safe and stable.

As solar power is generated by the panels, that energy is first directed to feeding the energy needs of the house.

Once this need is filled, the energy is then redirected to the grid. A bit like water always flowing to the lowest point, the energy will first be directed to your neighbour’s property, and as all those needs are met, it flows to the nearest transformer. So first to your street, and then your neighbourhood, and then to the wider grid.

That way, with support from the grid, the benefits of your solar can be shared by many.

Want to know how to connect your residential solar to your rooftop?