A home battery is simply a rechargeable storage device that hooks up to our solar array or our house power system. It holds the excess power we produce during the day so that we can use it at night—like when the sun sets or on those overcast days. It’s basically our own household power bank. Rather than returning our solar energy to the grid and receiving a small payment, we can use more of our own clean energy, which translates to less need for the electricity grid and a reduced power bill.

Why Would We Want to Get a Battery?

You may be asking yourself why so many homeowners are opting to install batteries on their solar systems. The reality is, there are a few good reasons. First, there’s the money aspect. Electricity costs are increasing, and feed-in tariffs have fallen over the years, so producing our own power makes a lot more economic sense nowadays than it ever used to. With the proper system, we can reduce our bills quite considerably—sometimes by as much as 80 percent.

Backup power is another big reason. If we’ve ever lost power during a storm or maintenance, we know how frustrating it can be. Batteries with backup features can keep essential appliances running during blackouts, giving us peace of mind when we need it most.

And then there’s the feeling of energy independence. Rather than drawing from the grid, particularly at times when demand is highest and power prices are highest, we can tap our own stored power. And by using a greater portion of our solar energy, our carbon footprint decreases, which is good for the environment.

What Kinds of Batteries Are There?

The majority of residential batteries nowadays employ lithium-ion technology. Lithium iron phosphate batteries are especially favored as they are safe, reliable, and have a long lifespan. Other lithium chemistries are employed by some systems, but LFP is normally the preferred alternative for homes in Australia.

You might have already heard of Tesla’s Powerwall 3—that’s a mighty battery with 13.5 kWh of capacity and backup power solutions. Germany’s SonnenBatterie is highly respected, particularly for energy-sharing schemes. Enphase has modular solutions so we can begin small and expand capacities down the line. Alpha ESS and BYD also have good options with good local representation.

How Big a Battery Do We Need, and What Will It Cost?

We determine the size of our battery based on how much energy we consume and when we consume it. Most residential batteries are in the range of 5 to 15 kilowatt-hours, and for a typical household, about 10 kWh tends to be the sweet spot. That capacity can provide most of our evening and nighttime electricity requirements.

Financially, batteries are not inexpensive. Today, installation is approximately $1,200 to $1,500 per kilowatt-hour. Therefore, a 10 kWh system could cost $12,000 to $15,000. It is an expensive upfront cost, but most feel the long-term financial savings and benefits well worth it.

What About Government Rebates?

A few government schemes nationwide have assisted with battery prices. Victoria, New South Wales, and South Australia have all provided interest-free loans or rebates at various times. A few of them are now closed, but there are new ones emerging as the old ones expire, so it’s worth investigating what you can get right now in your state or council area. Electricity retailers also offer extra incentives from time to time, particularly if we sign up to energy-sharing schemes or virtual power plants.

What is a Virtual Power Plant, and Ought We Join One?

Virtual Power Plants, or VPPs, are a brilliant idea. They link up several home batteries in one shared network that assists the electricity grid in balancing out when it’s in high demand. If we sign up with a VPP, our battery could feed excess energy back to the grid when the grid is most in need of it, and we get paid for it in the form of bill credits. It’s a win-win—we help the grid remain stable and are rewarded for it.

Businesses such as Tesla, AGL, and Amber Electric are operating VPPs right here in Australia. If we wish to make the most of our battery investment, becoming part of a VPP may be a fantastic idea.

What’s New in Battery Technology?

Battery technology keeps improving. Today, most systems come with smart energy management features, allowing us to monitor how much power we’re using, how much solar we’re producing, and how full our battery is—all from an app on our phone. Some even use artificial intelligence to figure out the best times to charge or discharge based on our habits and electricity prices.

Modular setups are becoming increasingly popular, too. That is, we can begin with a small battery and add more capacity in the future, which is wonderful if our requirements increase or if we acquire an electric car. On the topic of EVs, Vehicle-to-Home (V2H) technology is on the horizon, so our electric vehicles can serve as batteries for the house as well. It’s early days here in Australia, but a few pilots are already in progress.

Is a Home Battery Suitable for Us?

Whether we should have a battery or not depends on our own circumstances. If we have solar panels, power a lot at night, or would like power during outages, a battery would be a big help. If we’re driven by lowering our carbon footprint or wish to decrease dependence on the grid, that’s also a compelling reason.

Normal payback periods are typically between twelve and eight years, but this can be enhanced by joining a VPP or applying smart tariffs.