Why solar batteries are set to change the world
The first question we often get asked at Evergen, which I thought I’d cover today, is: “why batteries?” and “why solar batteries?”. Why are they getting so much attention around the world, and particularly in Australia at the moment? And you have to forgive me, I’m an engineer, so I have to use numbers and graphs to talk about things.
I think this picture really gives you a sense of what the challenge is. What we’re looking at here is, in the yellow colour, the electricity output from solar panels. And of course as the sun comes up through the day, that electricity output grows. It peaks in the middle of the day and then it goes down as the afternoon goes on. The blue lines are a graph of our electricity consumption in a typical Aussie home. And you can see here that most people use their peak electricity consumption is early in the morning around six or seven o’clock or later in the afternoon around somewhere between five and eight pm.
You can see from the picture that the blue lines are not overlapping the yellow lines. In fact, it’s almost the opposite. In many Aussie houses, the lowest electricity consumption happens throughout the middle of the day. And that mismatch is a real issue. It means that we buy solar systems, they make a lot of electricity in the middle of the day, but nobody’s home to take advantage of that electricity.
Traditionally, or certainly several years ago in Australia, that was less of an issue because we there were subsidy programs in place that paid you for the amount of electricity that came off your solar panels no matter whether you use it or not. In those schemes it didn’t matter if you were home to use the electricity because you simply got paid for it. Today that’s not the case and to get the most out of your solar system you really need to be trying to have your consumption line up with that solar production. That’s really hard for a lot of people where they’re not at home during the middle of the day or they don’t have appliances that they can schedule to turn on in the middle of the day.
And so the solution to this mismatch is to try and use a battery to save up that solar energy in the battery and make it available late in the afternoon when we’re getting home. That way there’s solar energy sitting in the battery we get home, we start to use a lot of electricity and we are using that solar energy stored in the battery rather than purchasing from the electricity grid.
That’s the fundamental reason that batteries are making sense today. One of the unique aspects in Australia is that the way our electricity bills are structured means, possibly Australia before anywhere else in the world, batteries are making economic sense. And so we’re seeing in Evergen that we have customers today who have seven to nine year paybacks from the battery systems and that means that after those seven or nine years, they’re essentially getting most of their energy for free.