Understanding solar batteries

Solar panels indisputably offer great value, but what about batteries? Here’s how they work, and what they offer.

An increasing number of Australian homes and businesses are choosing to add battery storage to their rooftop-solar systems. While the technology is still developing – and it’s not the best solution for everyone – it can be highly beneficial if deployed correctly.

At the City of Sydney we’re already taking advantage of battery storage at our new Alexandra Canal depot, where much of the energy generated from the facility’s 1600 solar panels is stored in a Tesla Powerpack battery. As technology advances, we hope to install more batteries across the council area.

The City if Sydney’s battery installed at Alexandria Canal Depot. Photo: Katherine Griffiths

What are the benefits of solar batteries?

Whether you’re a resident or running a business, adding a battery to your rooftop solar system has two main benefits:

Greater value from your panels. Batteries can store the excess electricity your solar system generates during sunny periods so you don’t have to sell it back to the grid at a low feed-in tariff.
Enhanced energy security. Batteries make you less reliant on your electricity provider and less impacted by rising electricity prices and can keep you powered up during blackouts.

What are the main types of solar batteries?

Battery technology is evolving rapidly, so seek out an accredited retailer to provide you with up-to-date information. But first, it’s useful to understand the two main types of batteries on the market:

Lead-acid batteries. These are similar to car batteries (but have thicker electrodes) and are the most popular type of solar battery in Australia. Lead-acid batteries are relatively cheap, well understood and readily recyclable.
Lithium-ion batteries. This technology, which is also used in laptops and mobile phones, is quickly becoming more popular for solar thanks to its superior storage capabilities and smaller size. However, these batteries are more expensive and recycling options in Australia are limited.

Are solar batteries worth it?

Based on current pricing, it takes about 20 years to recoup the expense of a rooftop-solar system plus battery, compared with about five years for a rooftop solar system on its own. Solar batteries may last up to 25 years, but it’s difficult to justify adding one to a rooftop-solar system based on cost alone.

But residents and businesses concerned about energy security may still want to consider installing a battery. If an uninterrupted electricity supply is important to you or your business, a battery system can provide you with certainty.

What about embedded networks?

People often confuse battery storage and embedded networks, but they are quite different. An embedded network is a private electricity network that connects users within a small geographical area – say, an apartment building. Embedded networks might source their energy from the grid or from a renewable source (such as rooftop solar) and might be connected to a battery system.