Why Battery Storage?
TLDR: The three main reasons for battery storage are:
Making use of excess electricity from solar panels
Reducing monthly or quarterly electricity bills
Providing backup power for essential circuits such as lights, refrigeration, internet modem, etc.
Where did Battery Storage come from?
Electricity is everywhere. We can’t see it, but most of the things we use in life are powered by it. Transportation is also beginning to adapt to electricity. Trains have relied on electricity for years, and now cars are trending in the same direction.
If we rely on electricity for most things, it makes sense to store it so we can use it when needed. Mobile phones wouldn’t be as useful without rechargeable batteries. Similarly, the rise of portable tools like drills, impact drivers, grinders, and vacuum cleaners shows how much we depend on batteries in daily life.
Australia has been at the forefront of adopting battery storage in homes. Given the size of the country, extending the grid to homes located many kilometres from the main line has often been uneconomical. Until recently, lead-acid batteries were the predominant form of storage. However, they were bulky, required well-ventilated spaces, and often needed regular maintenance—making them impractical for suburban homes.
The rise of lithium-ion battery storage has addressed many of these challenges. In the early 1990s, when lithium-ion batteries first became commercially available, the cost was about $7,500 USD per kWh. Today in Australia, you can buy high-quality LiFePO4 cells (without a battery management system or electronics) for around $220 per kWh. Prices have dropped dramatically, making battery storage far more economical.
How do Batteries work with Solar Panels?
If you have solar panels, storing excess electricity (that would otherwise be exported to the grid during the day) for use at night can make you more energy self-sufficient.
For example, exporting surplus energy to the grid might earn you 5–8c per kWh, whereas using stored energy at night could offset electricity that costs 30–35c per kWh. This reduces your power bill significantly. Electricity retailers are also moving towards time-of-use pricing, charging more during peak hours and less during off-peak periods. On such tariffs, you might pay 50c per kWh between 5–9 pm.
What is a Kilowatt-Hour?
We’ve introduced the term “kWh,” which can be confusing for some readers. Let’s break it down: kWh stands for kilowatt-hour—1,000 watt-hours. It’s the standard unit for measuring electricity consumption. Here are a few practical examples:
Electric kettle (1,800 watts): If boiling water takes 3 minutes, it uses about 0.09 kWh. At 30c per kWh, that’s roughly 2.7c per boil.
55-inch LCD TV (100 watts): Running it for 3 hours uses 0.3 kWh, costing about 9c.
LED lights (10 lights at 13 watts each): Running them for 5 hours uses 0.65 kWh, costing about 20c.
While these examples are straightforward, appliances like fridges and air conditioners are trickier to calculate. A fridge rated at 180 watts, though powered on 24/7, may only use 1.5–1.8 kWh per day because the compressor cycles on and off. Air conditioners also vary, using less energy once the room reaches the desired temperature.
How much could a solar battery save a homeowner?
If the price difference between exporting solar and buying electricity is 25c per kWh, and you use 12 kWh of stored energy at night, you could save about $3 per day—or around $1,100 per year. Savings could be even higher on time-of-use tariffs.
A third benefit of solar batteries is backup power for essential circuits during outages. Typically, these include lights, TV, fridge, and the internet modem. For example, if you’re hosting friends for the footy finals and the grid goes down, you wouldn’t even notice the power cut. While grid reliability is high in urban areas, rural areas experience more disruptions.
Backup power becomes critical during extreme weather events, such as storms that damage powerlines. After Queensland’s Cyclone Alfred, some households were without power for days. A generator can help in such cases, but a solar battery system is seamless—and silent. However, during overcast periods, you might need to ration energy if there isn’t enough sunlight to recharge the battery.
A fourth benefit of solar batteries is participation in Virtual Power Plant (VPP) schemes—this will be the topic of next week’s blog post.
Thinking About Adding a Battery?
Get in touch with us today and we’ll:
Check if you’re eligible for the rebate.
Provide a free consult to find you the right solar battery solution.
Connect you with a certified installer.
