Australian homes are blessed with sunshine that spans many hours over the course of the day. The moving sun is fantastic for solar but challenges the notion that solar panels should only be installed facing north. Peak over your neighbour’s fence and you’ll probably see that they have their solar panels installed on their north-facing roof. But is this the most efficient way to power your home? Will your north-facing panels provide enough electricity to power your home when you arrive home from work? Will they power up your Nutribullet, toaster, kettle, and TV during breakfast? Making use of all the orientations your roof has to offer might be the better option. Let’s take a look at what a split array could mean for your home and electricity bills.
What is a split solar array?
A traditional solar installation generally maximises the north-facing roof. This is due to the way the sun travels across the sky in the southern hemisphere. This was the perfect solar array installation practice when feed-in tariffs were high and the aim of the game was to send as much to the grid as possible. Now that feed-in tariffs are negligible, households should be aiming to use as much of the solar power generated as they can. Installing on only the north-facing roof could see a loss of 10-20% of morning and afternoon production when the sun is in the east and west. This is where splitting the array comes into play.
A split array is just as it sounds. Solar panels are installed on the north, west, and/or east faces of your roof. This is only achieved where your roof and chosen inverter allow it. Your installation will require the following:
- Ample roof space on varying orientations
- No or minimal roof obstructions, including shade from the surrounding area
- A string inverter with multiple MPPTs or microinverters. Power optimisers for string inverters with not enough MPPTs for the number of orientations required.
Let’s look at the types of inverters and what this all means.
String inverters and power optimisers
Your regular, run-of-the-mill solar inverter is a ‘string’ inverter. This means that your panels are connected to each other across one ‘string’ and then connected to your inverter to convert the DC electricity generated into usable AC electricity. Every string inverter comes with a minimum of two MPPTs (Maximum Power Point Tracking). If your inverter has two, then it can have two arrays installed on your roof. For example, this might mean you have 10 solar panels facing north and 8 facing west.
Power optimisers can take the inverter’s MPPTs and expand on them. Using our previous example, if I wanted to install additional panels on the east of my roof, I could add to one of the strings and then add power optimisers to all of the panels on that string. The reason why this is needed is that your string will only produce as much power as the weakest panel. So if your panels facing north on the string are pumping out 400W each, but the panels facing east are producing only 350W, all of the panels will be limited to 350W. Power optimisers are devices attached to each solar panel that adjust the panel’s output to ensure it operates at its maximum efficiency, even when other panels in the system are underperforming. They work with inverters to maximise the energy harvested from each individual panel, improving overall system performance.
In essence, power optimisers allow you to add additional orientations without negatively impacting the performance of your solar system. Check out our recommended products page for more information about string inverters.
Microinverters in a split solar array
Where string inverters limit the number of orientations of panels on your roof, microinverters allow for infinite possibilities! Microinverters, like those available through Enphase, are installed on each individual solar panel and convert the DC electricity to usable AC electricity. The performance of an individual solar panel has no bearing on another, meaning that you can install panels on every usable square inch of roof space.
Is it more efficient to split your array?
The simple answer is that it depends.
Here are some questions to ponder:
- How do you use your electricity during the day?
- Do you work from home?
- Is most of your energy usage in the morning and afternoon?
- What is your feed-in tariff rate?
- Do you plan to add battery storage?
- Do you own an electric vehicle?
Generally speaking, the most efficient solar array is one which faces north. An east-west solar array will produce 10-20% less over the day than an all-north-facing array.
However…
If your family uses the energy produced during the morning and afternoon sunlight hours, you may just be better off if your feed-in tariff is low. Some energy retailers offer higher feed-in tariffs during afternoon hours. West-facing panels would benefit the most from this.
If you work from home, and shift some of your high-energy-using tasks to the day, such as using your dishwasher and washing machine, then north-facing panels would be your best bet.
Remember: If your home allows it, a great way to make your solar system an all-rounder would be to install it on the north, east, AND west faces of your roof.
What type of solar array installation should I get if I have battery storage?
With home battery storage becoming commonplace in Australian households, the pendulum might just be swinging back to north-facing solar arrays. Just as in the days of old when high feed-in tariffs justified sending all your energy to the grid, the same could now be said for sending most of your electricity to your battery. This would be best achieved with all or most of your panels facing north. It’s not feasible for many families to use their electricity during solar production hours. With busy lifestyles taking people out of their homes for work and play, it makes sense to capture all of your solar energy for use when you are home.
With the advent of Virtual Power Plants, such as Origin Loop VPP, and home EV charging, the way we use electricity is changing. Battery storage will play a key role in the Australian way of life as our lifestyles evolve to energy independence.
The bottom line: Should I split my array or just install them all facing north?
While a nice and simple answer is probably what you’re looking for, the correct answer is that you need to speak with a solar installer. Your installer will factor in all of your current and future needs. If you don’t plan to add battery storage, you don’t have an EV, you work away from home, and your primary electricity usage is in the morning and afternoon, then a split east-west array will likely be suggested. If the opposite is true, then all north-facing panels will be recommended.
However, your home might not be able to avoid a split array. Your north-facing roof may be unusable for many reasons, leaving the only option of your east and/or west roof. The best solar system is the one that suits your home and your needs, and this is where your solar installer will shine.
While we can’t give you a definitive answer, we can do the next best thing! Complete our quick form and you’ll be contacted by up to 3 local solar installers. This service is completely free of charge and there’s no obligation to go ahead with any of the quotes. So, what are you waiting for? Begin your solar journey today and click the button below.
