The viability of solar power depends on both natural factors and man-made conditions. For example, abundant sunshine makes solar panels deliver more energy during their service life, while expensive electricity means each kilowatt-hour generated is worth more. In this case, the first aspect is determined by nature, while the second is influenced by politics and the economy.
Australia has both abundant sunshine and expensive electricity, which turns solar power into one of the most promising upgrades for residential and commercial properties. However, there are certain property characteristics that enhance solar power generation if presented together, making the investment even better. This article will describe what an ideal site for solar power looks like, but keep in mind you can still get an excellent return on investment even if your property is not exactly as described here.
Since Australia is in the southern hemisphere, most sunshine comes from the northern portion of the sky. As a result, the average solar radiation hitting a roof tilted to the north is higher than that received by a rooftop of equal area facing south. The opposite applies for countries in the northern hemisphere, such as the USA, where south-facing rooftops get more sunshine throughout the year.
East-facing roofs get more sunshine during the morning, and west-facing roofs get more sunshine during the afternoon, but in both cases the average radiation is less than for a north-facing roof. However, there are specific cases where these roof orientations are favorable:
Clear skies are beneficial for solar photovoltaic systems, since they start generating energy earlier and their output dies down later in the day, increasing overall energy production. However, it is important to note that not all mountains affect solar generation, only those located in the direct path of the sun in the sky. In the case of Australia, a mountain to the south does not affect generation, since the sun is never in that portion of the sky due to the country’s location.
Trees and buildings can also block the sunshine that would otherwise reach a solar PV system. Installing a PV system on a rooftop that is shaded all the time is generally a bad investment, since the output will be too low to compensate the cost of the system, and in these cases it may be better to invest in energy efficiency measures.
Small concentrated shadows such as those cast by signs or communication equipment must be avoided at all costs. Solar PV systems use many electrical circuits connected in series, which means that overall performance drops even when just a portion of the system is affected:
However, if your rooftop is only subject to light or moderate shading, the solution is to simply avoid areas that are covered by shadows. Just keep in mind that the sun’s position in the sky changes throughout the day, and so does the direction of shadows. Solar panels must be arranged so that the effect of shadows throughout the day is minimal or zero – however, if you work with professionals, they will take care of this.
Energy produced from a solar photovoltaic system is more valuable when you can consume it immediately, since you save the full retail price of each kilowatt hour. Therefore, solar power tends to offer the highest return on investment when its entire output is used. If there is surplus generation you can still benefit from it, but the value of each kilowatt-hour is diminished:
In the first case the monetary value of each kWh is reduced, and in the second case you save the full retail price but have a higher system ownership cost, reducing the net benefit. Nevertheless, both options are viable considering the high price of electricity in Australia – they offer great savings, but maximum savings are only achieved when you consume electricity as soon as it is generated.
Due to its sheer size, Australia has a broad range of climate zones. In general, more sunshine translates into increased solar energy generation throughout the year. Most of the Australian landmass gets an average solar radiation above 4 kWh/m2/day, but the sunniest locations towards the center and northwest get over 6.5 kWh/m2/day.
Assume you have two solar PV systems of the same installed capacity, but located in opposite regions of Australia:
In this case, the first system will generate roughly 50% more energy, assuming the same capacity and similar site conditions. Since the installed cost is similar, the first system has a return on investment that is 50% higher and a payback period that is around 33% shorter.
Depending on the type of photovoltaic modules, a solar array generally weighs between 10 and 20 kg per square metre. Therefore, the structural condition of your rooftop should be assessed before proceeding with any installation. Like in the case of shadows, this will be covered if you are working with professionals.
This article describes an ideal location for solar power, but you can benefit from the technology even if your property does not meet all conditions perfectly. Keep in mind that Australia gets enough solar radiation to meet its yearly energy needs 10,000 times; unless you have an unusual combination of unfavorable site conditions, you can expect to save a lot of money with solar power.