By 2024, around four million rooftop solar PV systems had been installed in homes and businesses across Australia, but there is a catch. Solar panels do their best work only in the middle of the day, while homes and businesses often still need the most energy in the evening. Solar batteries solve this problem by storing excess energy generated during the day so it can be used later when you need it the most.
How solar and battery systems work together
Solar and battery systems work together in a simple but integrated setup. During the day, solar panels generate electricity from the sunlight to power a home or businesses. Any extra energy can be stored in a battery instead of being sent back to the grid.
The battery supplies stored energy for you to use it later. This reduces reliance on grid electricity when solar generation drops, such as at night, during peak demand periods, or when power outages. So, solar is how you get the electricity from sunlight, and the battery is how you save that electricity for later.
Following changes to the Renewable Energy (Electricity) Regulations 2001, solar batteries are now eligible under the Small-scale Renewable Energy Scheme (SRES). These changes are making solar and battery systems an increasingly practical option for Australian households and businesses.
In practice, it allows households and business to:
- make better use of rooftop solar energy,
- reduce household electricity bills,
- greater control over how and when energy is used,
- store cheap renewable energy,
- lower pressure on the electricity grid during peak periods,
- reduce reliance on gas and network infrastructure,
- improve grid stability and energy resilience,
- support greater renewable energy adoption and lower emissions.
Understanding battery capacity: nominal vs usable
Check the difference between nominal capacity and usable capacity when you purchase a solar battery for your home or business.
Nominal capacity (total size)
It’s the total amount of energy a solar battery can store. The maximum capacity under ideal conditions, and it’s typically the number shown on product specifications that is measured in kilowatt-hours (kWh).
For example, a 10kWh battery can technically store up to 10kWh of solar energy when fully charged. But keep in mind that you can’t use all of them, and that’s what usable capacity refers to.
Usable capacity (what you actually get)
Usable capacity is the portion of stored solar energy that you can actually use in practice. This is usually lower than the nominal capacity, as batteries are designed to:
- avoid full discharge to protect their performance and lifespan,
- prevent extra wear on the battery,
- keep power running safely and reliably each day.
In real terms, a 10kWh solar battery may only deliver around 8–9kWh of usable energy, which is what will be available to power a home or business in the evening or during peak demand periods.
Understanding the difference between nominal and usable capacity is important before you choose a solar and battery system. Usable capacity shows how much stored energy you can actually use, which directly affects savings and overall system performance.
It also helps when comparing systems and understanding possible incentives, as programs like the SRES are usually based on usable battery capacity rather than the battery’s full size.
Why Australia is seeing a battery boom
Solar battery adoption is still relatively low, with only around one in 40 households installing batteries, largely due to the high upfront cost. However, Australia’s interest in batteries continues to increase over time.
One of the biggest drivers is the Cheaper Home Batteries Program to help households, businesses, and communities reduce upfront costs. You can get discounts of around 30% available for eligible systems to install various small-scale battery systems (5kWh to 100kWh).
Delivered through the SRES, these incentives are making battery storage more accessible and improving project economics, particularly when combined with existing solar systems.
What battery storage means for Australian businesses
For businesses and property owners, battery storage provides greater control over how and when energy is used. By storing excess solar energy, you can rely less on grid electricity and use stored power during peak pricing periods. You can reduce energy costs and make electricity expenses more predictable over time.
Beyond immediate cost savings, battery storage can improve the long-term performance of commercial and public assets. Integrating batteries with solar systems increases overall energy efficiency and supports more sustainable operations throughout the life of a project.
Batteries also support greater renewable energy use that contributes to emissions reduction and broader nation sustainability goals. For businesses and organisations considering solar and battery systems, the next step is identifying the right solution for their operational and energy needs.
At Arche, we work with clients through expert solar advisory services to assess, design, and deliver tailored solar and battery systems aligned with project goals and long-term performance.