1 | h1

Can You Go Solar in Australia with a South Facing Roof?

Short answer: Yes!

Homes and businesses located in sunny areas will see the greatest benefit from solar panels. But even those in more temperate regions and with south-facing roofs can reap decent rewards. This is because solar panels work by converting sunlight into electrical energy. And while the sun may not be as intense in some parts of Australia as others, there’s still plenty of sunlight to generate solar energy.

In fact, the average home or business owner can still expect to reduce their energy bills after installing south-facing solar panels. Do you want to save money on your energy costs? Then solar panels are definitely worth considering – no matter where you live in Australia or which direction your roof faces!

Why solar panels facing south make sense

Solar technology has progressed rapidly in recent years, making it more efficient and cost-effective than before. Solar panels mounted on a roof facing south are now a viable option for many homeowners and businesses in Australia.

Nowadays, even solar panels on a somewhat shaded roof can be a worthwhile investment. And if your roof faces south – once referred to as the worst direction – it’s no longer a problem!

Why the shift? Solar panels have gotten a lot less expensive and more efficient in recent years. The price of solar cells was around $5 per watt in 2010. Today, it is much lower: under $1 per watt. And it is expected to continue to decrease over the next few years.

What does this signify for you? If you want to install solar panels on your roof, you no longer need to worry about pointing them north. Any direction will work!

South-facing panels may not produce as much energy as north-facing ones, but they will still help you save money on your power bills. So don’t let a shady tree or other obstruction blocking one side of your roof prevent you from going solar.

Solar panels on your entire roof can save you a bundle on energy costs!

So let’s examine why mounting solar panels even on a roof facing south for most homeowners is likely to be a wise investment.

Want to skip the technicalities and find out how quick the payback period is? Click here.

Solar panels facing south – main features

The output from solar panels facing south is strongly influenced by various physical circumstances, including:

  • Location: As you go further south, solar panels facing south produce less energy. Darwin produces more solar energy from solar panels facing south than Hobart.
  • Tilt Angle: The less the pitch of your roof, the more solar energy panels facing south will generate. A very steep roof facing south may significantly reduce solar energy output.
  • Lower Winter Output: The output from solar panels facing south during winter is less than half of similar solar panels facing north.

Location

Why is location important? Panels facing south are affected by the local climate; therefore, their output is less than that of panels facing north. However, when we compare Australia’s most northern city, Darwin, with the most southern capital city, Hobart – the difference is obvious.

With a 15-degree tilt, the yearly production from panels facing south in Darwin and Hobart is shown below:

  • Darwin: the annual solar energy obtained from panels facing south is 88% of similar panels facing north.
  • Hobart: The annual solar energy obtained from panels facing south is 74% of similar panels facing north.

Why the difference?

The sun is nearer to the equator at higher elevations, and Darwin is closer to the equator. In fact, Darwin is 3,400 kilometres closer than Hobart.

Graph 1 below compares the annual average output of solar panels facing south with that of panels facing north at the same angle (15°) in cities in Australia (from North to South).

 

Tilt angle

How does the tilt angle affect solar panels?

Angles of 15° and 22.5° are typical for Australian solar installations. If your roof slopes less, the greater the output from solar panels. Why? The 15°-22.5° tilt angle is optimal for solar panels in Australia because it allows the panels to capture the most sunlight possible throughout the day.

This angle allows the sun to hit the panels directly during the day, rather than at a low angle where the sunlight would be less intense and less effective at generating power. Additionally, this tilt angle helps maximize air circulation beneath the panels, which helps keep them cool and prevents them from overheating.

While a tilt angle of 15°-22.5° may be optimal, that doesn’t mean that solar panels can’t still generate electricity at other angles. It’s just that they won’t do it as efficiently as they could if positioned at 15°-22.5° degrees. Solar panels work by absorbing sunlight and converting it into electricity. The more direct the sunlight hitting the solar panel, the more efficient the conversion will be.

What is the difference in output for each tilt angle?

Let’s examine how tilt affects the energy output for north-facing and south-facing solar installations in Darwin and Hobart.

The output of solar panels facing south is shown as a % of the output of solar panels facing north.

Increasing the tilt angle of south-facing panels in Darwin results in a 6% decrease in output.

Increasing the tilt angle of south-facing panels in Hobart results in a 10% decrease in output.

How tilt angle affects solar panels in Sydney

Let’s look at Sydney, Australia’s biggest city, and how changing the tilt angle affects the annual output from 1 kW of solar panels facing north compared to 1 kW of solar panels facing south.

Graph 2 shows the results.

In Sydney, the output of solar panels facing north gradually increases as the tilt angle increases, reaching the optimal output at 32.5°. Any further increase in tilt angle results in a slight decrease in output.

It’s a different story when the tilt angle is increased for solar panels that face south. Each degree increase in tilt angle results in a corresponding decrease in output.

Solar panels on a roof in Sydney that faces south and slopes at 45º only generate around 66% of the annual output produced by solar panels on a roof facing south with a typical pitch of 22.5º.

Mounting racks to adjust the tilt angle

Tilt racks can allow you to mount solar panels on a roof facing south while still orienting the panels north.

Tilt racks are a decent solution for a flat roof, but for sloped roofs, you must consider that:

  • Installation can be expensive
  • Racks can restrict how many solar panels will fit in the roof space available
  • You may need local council approval

Typically, it makes more sense to install more solar panels due to their reduced cost in recent years rather than spending on adjustable tilt racks.

What about lower output in winter?

In summer, some locations with solar panels facing south outperform solar panels facing north installed on roofs with a shallow slope.

In Graph 3, you can see the average daily energy from 1 kW of solar panels in December in each city. The comparison is 1 kW north-facing vs. 1 kW south-facing, both at a tilt angle of 15°.

In three cases, Darwin, Brisbane, and Perth, solar panels facing south produce more energy in December than panels facing north. All other cities show little to no difference in output.

But when we examine the output in June, the story is very different. June is considered the poorest time for generating solar power in many locations.

In Graph 4, you can see the average daily energy generated by 1 kW of solar panels in June in each city. The comparison is 1 kW of solar panels facing north vs. 1 kW of panels facing south, both at an angle of 15°.

In Darwin, in June, the output from solar panels facing south is 64.5% of that from panels facing north. In Brisbane, the output is closer to 60%, and in other cities, it is less than 50% of that of north-facing panels.

What does this mean?

Do you consume more electricity at home for air conditioning in summer than heating in winter? If so, low output in winter shouldn’t be an issue. But, if you live in Canberra, Melbourne, or Hobart, then you probably consume more energy for heating in winter than cooling in summer. And that makes solar panels facing south a less appealing option.

City-specific data

So how does direction affect solar energy generation for each capital city?

Below is the data for each city showing the direction and percentage of maximum output 100% obtained for the two tilt angles: 15° and 22.5°.

NOTE: the optimal direction is north (100%). The output value shows the average annual output for 1 kW of solar panels facing in various directions compared to panels facing north at the same angle.

Average annual and daily kWh values for panels facing north are also given for each city.

The latitude or distance south from the equator is also given for each city.

Panels facing east generate more solar energy during the morning than during the afternoon. It’s the opposite case for solar panels facing west.

Households benefit more from consuming solar energy generated instead of exporting it to the power grid via a Feed-in Tariff (FiT). So the period of maximum energy consumption during the day is a vital factor to consider before positioning solar panels.

Darwin

Darwin is the most northern city in the country. It has wet and cloudy summers but dry and clear winters. Although Darwin is known for its cloudy climate, it enjoys the highest average solar output. Its location far north and the local climate result in minimal variance in the annual solar output for a 15° and 22.5° tilt.

  • Latitude: 12°26′
  • Distance from equator: 1,386 km

Average annual output:

  • 15°, 1,691 kWh
  • 22.5°, 1,691 kWh

Average daily output:

  • 15°, 4.63 kWh
  • 22.5°, 4.63 kWh

Brisbane

Brisbane experiences rain and cloud during the summer, similar to Darwin, but to a lesser degree. The climate is mainly clear and dry during winter.

  • Latitude 27°28′
  • Distance from equator: 3,054 km

Average annual output:

  • 15°, 1,571 kWh
  • 22.5°, 1,599 kWh

Average daily output:

  • 15°, 4.30 kWh
  • 22.5°, 4.38 kWh

Perth

Perth enjoys mainly clear skies, and solar output is close to that of Darwin, even though Perth is more than 2,000 km further south.

In WA, Feed-in Tariffs only apply to 6.66 kW solar systems or smaller ones, so larger capacity solar installations for households are not typical. South-facing solar panels on homes are also uncommon in Perth.

  • Latitude 12°26′
  • Distance from equator: 3,553 km

Average annual output:

  • 15°, 1,655 kWh
  • 22.5°, 1,686 kWh

Average daily output:

  • 15°, 4.53 kWh
  • 22.5°, 4.62 kWh

Sydney

Enjoying warm summers and mild winters, Sydney doesn’t have such well-distinguished wet and dry seasons, unlike some other capital cities.

  • Latitude 33°52′
  • Distance from equator: 3,766 km

Average annual output:

  • 15°, 1,470 kWh
  • 22.5°, 1,509 kWh

Average daily output:

  • 15°, 4.03 kWh
  • 22.5°, 4.13 kWh

Adelaide

Adelaide enjoys clear skies during summer. As a result, solar output is marginally lower than in Brisbane, despite being further to the south.

  • Latitude 34°56′
  • Distance from equator: 3,884 km

Average annual output:

  • 15°, 1,477 kWh
  • 22.5°, 1,513 kWh

Average daily output:

  • 15°, 4.05 kWh
  • 22.5°, 4.15 kWh

Canberra

The climate in Canberra results in a high level of solar output. But during winter, panels facing south produce minimal solar energy.

  • Latitude 35°18′
  • Distance from equator: 3,923 km

Average annual output:

  • 15°, 1,482 kWh
  • 22.5°, 1,523 kWh

Average daily output:

  • 15°, 4.06 kWh
  • 22.5°, 4.17 kWh

Melbourne

With the most cloud cover of all the capital cities, Melbourne has ever-changing weather, but despite this still produces a decent amount of solar.

  • Latitude 37°49′
  • Distance from equator: 4,205 km

Average annual output:

  • 15°, 1,329 kWh
  • 22.5°, 1,362 kWh

Average daily output:

  • 15°, 3.64 kWh
  • 22.5°, 3.73 kWh

Hobart

As the most-southern capital city in Australia, Hobart produces the least amount of solar output. But the good news is that it can still be worthwhile going solar in Hobart.

  • Latitude 42°53′
  • Distance from equator: 4,768 km

Average annual output:

  • 15°, 1,152 kWh
  • 22.5°, 1,142 kWh

Average daily output:

  • 15°, 3.16 kWh
  • 22.5°, 3.13 kWh

Are south facing solar panels worthwhile?

An online solar calculator is the best approach to determine whether or not south-facing solar is worthwhile for you. It will make all of the calculations and estimate how long it will take for your solar system to pay for itself.

What is the optimal payback period that makes solar worthwhile?

This is a question that individuals must answer for themselves. But on a typical unshaded roof in Australia, the return from south-facing solar should be enough to attract most homeowners.

Figuring out the payback period

You can use a solar calculator to figure out how much energy your solar panels will produce over a year. This will be based on where they face, the slope of the roof, cost of grid electricity, and solar feed-in tariff. Two other crucial factors are whether you have a solar battery or not and your current annual spend on electricity.

Okay, it’s a lot of data to input. But a decent solar calculator will provide default values for a typical Australian family home as a guide. So if you’re unsure, go with them for now to get an estimated payback period.

To assess south-facing solar in every capital city in order to obtain an estimate of the simple payback time, we’ll consider the following:

  • Size of the solar system
  • Orientation (direction) and tilt angle
  • The purchase cost of the system
  • Local electricity prices
  • Local Feed-in Tariffs

System size

Let’s say the system has a 6 kW panel capacity installed. In some areas, 6 kW is the maximum capacity single-phase residential solar system dwellings are allowed to install.

Orientation/direction and tilt angle

The system will be oriented directly south and tilted at a 23° angle. Solar power systems with all of their panels facing south are uncommon. But we’ll assume for the sake of argument that this is a worst-case scenario.

System cost

We’ll assume the purchase price is $6,000. Yes, that price won’t get you the most efficient panels or solar inverters available. But it would cover a system built with reputable components from an experienced contractor.

Electricity prices

To obtain an accurate payback period estimate, we need to know the local cost of electricity. You may need to calculate the amount yourself. For our analysis, we’ll use the default values for the calculation.

Feed-in tariff

FiTs are subject to changes, so we’ll use the default values given by the solar calculator for each state.

Self-consumption

We’ll use the default self-consumption values given by the solar calculator for each state based on a typical Australian family home.

The results for the estimated payback periods for each capital city are as follows:

Hobart has the lengthiest payback period for solar, at 7.2 years. Not surprisingly, Hobart has the worst solar production in the country. So we would expect poor performance from solar panels facing south in Hobart. Although the payback period is the longest, it’s still not a terrible investment for locals who can self consume most of the solar they produce.

A payback period of seven years for an investment in solar was acceptable in the old days. Whether or not it’s worthwhile for you will come down to your personal circumstances. You have little to lose if you know you’ll stay in your home for more than seven years. And even if you leave before then, a high-quality solar installation boosts the value of your home on the market.

Melbourne has the second-longest payback period at 6.4 years. Influencing factors include the local climate and low energy costs. Also, we didn’t include the Victorian Solar Rebate of up to $1,400 that is currently available. So if we factor that into the calculation, the payback period is even shorter, only 3.8 years.

Adelaide comes out on top, with a payback period of only 4.9 years. And that’s without factoring in the Victorian solar rebate. Adelaide isn’t that sunny, but high electricity prices and favourable Feed-in Tariffs result in a quicker payback period.

Conclusion

South-facing solar is not as good as north-facing solar – but still worthwhile in many cases.

Installing solar panels facing south won’t make sense for everyone.

Do your goals include saving the planet, saving money, having greater energy independence, or ramping up capacity for a home solar battery, electric vehicle, or other increased energy usage?

Then south-facing solar can make perfect sense. Do you have a south-facing roof with slight or no shading and can put solar panels there without difficulty? Then you’ll likely benefit from doing so!