Australia’s first intelligent home energy system: how one Sydney couple saved $1800 in a year

The smart home revolution is here and is set to change the way we live for the better. Intelligent home energy systems are only just being made available now, so what’s it really like to live with one, and do the energy savings live up to the hype?

We talk to Greg Maclean, owner of an Evergen Intelligent Home Energy System, the first in Australia, to see what his experience has been after a full year of operation.

What sort of home do you have and do you use much electricity?

We live in fairly typical two storey house in Sydney’s south. It’s just myself and my wife but we do a lot of cooking and with the grandkids coming over and the pool running, we tend to be quite big users of electricity.

Why did you end up installing an intelligent energy system?

In the last few years, our electricity bills were rising steeply. Over summer we were paying $700 a quarter despite running the pool pump, dishwasher and clothes dryer at night. At the same time, technologies like solar and batteries were becoming cheaper and better. So when I was asked if I wanted to be part of a trial of a new energy system from CSIRO, I was very happy to accept.

“…we can be environmentally responsible but also have our cake and eat it, because we don’t have to use less power to save money.”

So you did it for financial reasons? To save money?

It made sense for financial reasons, but also, this is the future. I believe that the current model of supplying electricity is not sustainable environmentally. Generating clean energy at home is a way that we can be environmentally responsible but also to have our cake and eat it, because we don’t have to use less power to save money.

What size system did you install at your house?

Initially, we had a 7.5kWh battery system with 5.7kW of solar. That’s quite a large solar system, but with the battery storage, I wanted the biggest system I could fit on my north-facing roof.

Were you worried about being the first in with new technology?

Well, what’s new? If you look at the major parts of the system, solar panels and a lithium ion battery, it’s technology that has been around for a long time. What is new is the intelligent infrastructure that ties it together with the home and the grid. I was comfortable installing the system knowing that the CSIRO team are behind the development and technical investment.

And what was actually involved to install your system?

The installation was fairly straight forward. The battery system is an integrated system about the size of a small fridge. They wheeled it into the garage and drilled through the wall to connect it to the switch box and the PV feeder cables, which was basically it.

What I liked about the system was that it’s modular, so that if we want to add more battery capacity later on, then we can just open the door and slot a new cell into the spare racks, so there’s no more electrical work needed.

What about the inverter and energy management system?

It’s all integrated into the one unit so you don’t see that at all. Ultimately that’s the way things have to go. Don’t expect that if someone goes down to Bunning’s and buys all the bits and puts them together that you will end up with an integrated system that does anything like what this can do. It’s not just the hardware but the software that is equally important.

And you’re still connected to the grid?

Yes. We’re still connected and we draw power from the grid when we need to. We also sell excess power back to the grid and get a credit on our quarterly bill.

Once it’s all installed and switched on, what does the system actually do?

The intelligence that runs the system uses weather forecasts to estimate solar production and, based on our consumption pattern, works out the best way to maximise savings. For example, if the forecast is for cloud, the system may fill the battery from the grid using cheap off peak power to use during peak and shoulder periods later on.

The nice thing for us is that it all just runs in the background so we don’t have to worry about it.

And does the intelligence work?

It definitely works, you only have to look at the savings. It is also getting better all the time as it learns. The beauty is that it’s tailored to our requirements. For example, when our electricity tariffs changed, it picked that up automatically, and adapted to maximise savings.

“… the savings are about $1,800.”

After a full year using the system, what sort of savings have you seen?

There are a couple of ways to look at it. If you just compare the year before I got the system vs the year after, then my bill is about $1,500 dollars lower, which is reduction of 65%. That’s pretty good, but what you’ve got to take into account is that power prices went up during that time and we’re using more power. So the better way to look at it is to compare our bill over the year to what we would have paid if the system wasn’t there. Then the savings are about $1,800.

You’ve used more energy since you got the system? Isn’t that counter-productive?

We’re generating it for free so why not use it?

You’re a professional investment analyst. How do you look at buying an energy system in terms of an investment? Was it important to you that the investment equation stacked up?

Of course the dollars have to stack up. But I think people get all tied up in knots trying to calculate the financial return. Trying to look years in the future with an evolving technology to figure out exactly what you’ll save is fraught. Where are electricity prices going to go? Probably up, but by how much? What’s the intelligence system going to be able to do in three years that it can’t do now? Probably quite a bit, but you can’t put that into a spreadsheet. So there ends up being all this uncertainty and your analysis just ends up with spurious accuracy.

“… the opportunities to save money using the intelligence system will grow over time.”

The way I looked at it was that the payback, just based on today’s electricity price, was around 10 years, which is within the life of the system. After that if I need to do something like replace a battery cell, then I’ll be able to do that very cheaply and that gives me a whole bunch more value. Just look at how cheap solar panels are compared to 10 years ago. On the other hand, the opportunities to save money using the intelligence system will grow over time. So I keep it simple and focus on those fundamentals and it’s a pretty straight forward choice.

But, we’re reasonably comfortable financially and for us it’s as much about improving our lifestyle and just feeling good about how we use power, rather than a purely financial decision.

You say that it improves your lifestyle. What does that actually mean?

We’ve found now, for instance, that we’ll turn the pool heating on when we wouldn’t have before. And we’re happy to do that because it’s free. So the grandkids can come over and enjoy a nice warm pool and we’re still saving money and helping the environment. So that’s what I mean about having your cake and eating it.

And what do you see the future holding? Do you expect your savings to improve?

We recently added another 1.5 kWh, which brings our total battery capacity up to 9 kWh. It will be great to see the impact it has because at the moment we still end up exporting a reasonable amount of solar at times when we’re not at home and the battery is already full. So with the extra capacity, we’ll be able to store that power and use it to offset our bill.

Then down the track when the system is able to do things like turn my pool pump on when we have excess solar power, there’s a lot more value to be had. Longer term I may be able to do things like help support the grid and get paid for that. There are all these possibilities available because it’s a proper intelligent system. That’s why people say that this is the future.

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