Solar Battery Storage
Everyone loves the idea of going “off the grid” and becoming independent from their electricity company. At face value, storing electricity in a battery seems like a pretty basic concept, but there are several important aspects of battery storage that most people are yet to understand. We have clearly documented them below.
Australian consumers understand the financial benefits and environmental benefits of solar and have responded well to the call for sustainable, clean energy. An aerial fly over will show you just how many solar panels are now out there!
Choosing the right system for you will depend on your energy usage patterns, your home or business and your budget. But don’t worry, we can help you to find the most effective solution for your circumstances.
Benefits of Battery Storage
- Store unused energy that your solar power system produces for use after dark
- Purchase cheap energy during off-peak times and store it for use at peak times
- Access back-up power when you need it
- Feed energy back into the grid (earn $ at peak times)
- Off-Grid Capabilities (in some cases, but not recommended just yet)
- Instead of passing the benefit of unused energy back to your electricity company at a very low tariff, you can use it yourself when you would otherwise be buying it at a higher tariff from your electricity company.
- Rely less on your electricity company
- Potential to buy electricity from your energy provider at times of the day when your tariff is low on a TOU tariff (time-of-use tariff) and spend less buying electricity from the grid, because you can store it for use at peak times, when electricity companies charge a much higher tariff.
- Set your battery to enable back-up power during a power outage so that you can keep your fridge and other key electrical circuits operating.
Types of Battery Storage Systems
- AC Coupled Storage
- DC Coupled Storage
- Hybrid inverters
AC Coupled Storage
AC coupled storage is the most common type of storage solution being used in Australia. AC coupled solutions have a number of significant advantages over DC-coupled systems.
Benefits of AC Coupled Storage:
- Ability to draw power from the grid, allowing homeowners to purchase power at cheaper rates, ensuring you don’t draw from the grid at peak times when power is most expensive.
- Provide battery back-up and store excess solar energy.
- Operates independently of the home’s solar power system
- They can be retrofitted while allowing you to draw on other energy sources such as ancillary generators.
- Reliable, trusted and time-proven.
Negatives of AC Coupled Storage:
- Less efficient than DC Coupled Storage
- Less cost-effective at storing solar energy as DC coupled
DC Coupled Storage
DC Coupled Storage systems are installed between the solar panels and the inverter.
Benefits of DC Coupled Storage:
- Detects when there is excess power production and channels it to the battery storage.
- If your household is using up more power than your solar panels are producing, the stored power is then released to your inverter and from there into your home’s system.
- Eliminates unnecessary conversions between DC and AC later on, because power is stored in the batteries before being converted to AC.
- Cost-effective and Efficient
- Generally easy to retrofit into existing systems
Negatives of DC Coupled Storage:
- Inability to draw power from the grid and store it in your battery for use later on during high peak periods.
- The biggest negative for most homeowners is that a DC Coupled storage solution will not provide power during a grid outage.
Hybrid Inverters
There are remarkable benefits in having a Hybrid inverter, because Hybrid inverters are specifically designed to couple solar power systems with battery storage. Whilst there are benefits in having AC Coupled Storage and benefits in having DC Coupled Storage, with a Hybrid inverter, you get the benefits of both! A key benefit is that you can store power in the battery before it’s converted from DC to AC, eliminating unnecessary further conversions. As it is also AC coupled, you can still incorporate features such as battery back-up and the storing of power during cheaper non-peak periods. All the monitoring is also conducted by a centralised unit, so you don’t have to worry about separate monitoring packages for both your storage and solar power systems. We are now seeing more and more of these units as they’re a great fit for residents looking to incorporate solar and storage together into one complete, powerful package.
Benefits of Hybrid Inverters:
- Store power in the battery before it’s converted from DC to AC, eliminating unnecessary further conversions.
- Many have optional back-up power feature via an ATS (Automatic Transfer Switch) to provide power in case of a grid electricity outage.
- Storing power during cheaper non-peak periods.
Government Incentives
The continuing voltage rise as the massive increase of solar generated energy is exported to the electricity grid has caused an instability to the grid. In response, the government has allowed the electricity companies to significantly reduce feed-in tariffs and they have introduced incentives to help stabilise the export levels of solar generated electricity into the grid.
The DEBS Scheme (Distributed Energy Buyback Scheme)
The Distributed Energy Buyback Scheme (DEBS) offers eligible customers a time of export payment for electricity they export to the grid, including from rooftop solar PV systems, batteries and electric vehicles.
The DEBS Scheme provides those exporting to the grid far better rates during high-peak hours, encouraging the storage of energy gathered during the day, rather than releasing it as soon as it’s generated in the height of noon. Learn more about DEBS https://www.wa.gov.au/organisation/energy-policy-wa/energy-buyback-schemes
With the current incentives in Australia, and batteries being more affordable than ever before, there has never been a better time to start benefiting from solar battery storage solutions.
The Difference Between a Solar Inverter and a Battery Inverter
A solar inverter converts DC power (Direct current) from the panels into AC power (alternating current) for your home or business.
A battery inverter converts DC power from the batteries into AC power for your home or business and converts AC power from the home or business (from your solar power system and the grid) to DC power so that it can be stored in the battery.
Batteries can only store energy in DC power form. Therefore the battery inverter will continually be converting the power both ways, depending on your consumption and storage. Battery inverters are engineered to suit a specific metering device.
Installing Solar Batteries
There are several things to consider when looking at the best options for installing the above solar battery storage solutions.
Retrofitting Battery Storage to an Existing Solar Power System
Retrofitting battery storage to an existing solar power system involves 3 things:
1. A Battery Storage System (The Battery)
2. A Battery Inverter (This does not replace the job of your current solar inverter, but it is still required)
3. A new Metering Unit (seperate to the one your electricity company provides)
If you have a hybrid inverter, it can operate as your solar inverter and your battery inverter, all in one!
NB. Retrofitting battery storage to an existing solar power system will not necessarily give your home or business the ability to use back-up power during a grid power outage.
Metering Unit
The metering unit is attached close to your switchboard and communicates with the battery inverter so that it knows how much energy your home or business is using, and regulates how much energy is being stored and utilised.
Battery Compatible Systems
Pretty much all solar power systems are battery-compatible, meaning that yes, you can add battery storage to them if you also add some additional components during installation. They require a battery inverter and all the necessary components. Most of the battery-compatible systems can not actually be configured to provide back-up power, because they still rely on energy from the grid to operate.
Battery-Ready Systems
A battery-ready system is one that already has the additional components, like a battery inverter installed. Some people choose to purchase a battery-ready system without the battery, so that they can simply add a battery at a later stage, perhaps after some of the solar savings have helped them to afford the battery. Hybrid inverters are a great example of a battery-ready system, because the battery can be directly connected to the systems inverter and metering unit.
Battery Back-up Ready Systems
A battery back-up-ready system is a system that can be configured with an ATS (Automatic Transfer Switch) to provide power in case of a grid electricity outage.
Not all hybrid and battery inverters have the ability to provide back-up power during a grid power outage.
Back-up Power
Most people assume that having a battery means that you are covered during a grid power outage, but this is not the case. Not all battery inverters and hybrid inverters are able or even compatible for providing back-up power. Generally, if backup power is a need, then the best option is usually a Hybrid inverter system and in many cases it is advisable to replace your own inverter with a hybrid inverter.
The capacity for a system to provide back-up power during a grid power outage, requires additional components. The additional components are required to stop power from being returned to the grid during an outage. New systems will have an ATS (Automatic Transfer Switch), but existing systems might not. The ATS automatically turns off feedback into the grid during a power outage and reactivates when the grid is functioning again.
There are complex things to consider when making an existing system suitable for providing back-up power. If your inverter mistakes power that is being generated by the back-up system for power that it thinks is being generated by the grid, the inverter will not be able to regulate the power level and will shut the entire system down. Some back-up inverters now have the ability to control the inverter so that this doesn’t happen.
Good quality Hybrid inverters are great because each of the components are already contained within the Hybrid system, so you can avoid some of the above issues.
Back-up power supplies do have their limits and generally will not be able to cope with full output of all appliances, like large air-conditioning units. Trying to use them during a black-out can cause your back-up system to shut down, simply because it cannot meet the demand. So it is wise to configure your back-up system to be connected only to a circuit or circuits where your essential items are connected, ie: refrigerators, security alarm system, internet modem, main lighting circuits etc….
