Solar power explained: Everything you need to know

Living Well | RACV | Posted on 04 October 2019

Shining a light on the most frequently asked questions about rooftop solar power.

Thinking of installing a rooftop solar system but have no idea where to start or what questions to ask? You’re not alone. Though increasing numbers of Australians are choosing to go solar, there is widespread confusion about which systems to choose, how to get them safely installed and whether or not you’re eligible for government rebates.

To help shine a light on all things solar power, we’ve spoken to the experts. Here’s everything you need to know about buying, installing and maintaining rooftop solar power for your home, plus how to choose a trustworthy retailer.

Solar panels on red-tiled roof

Solar power explained: Everything you need to know 

What is solar power?

In simple terms, solar power is electricity directly generated by sunlight.

How do solar panels work? 

Solar photovoltaic (PV) panels absorb the energy in sunlight and convert it into direct current (DC) electricity that you can use in your home, or sell it back to the grid. Each solar panel is made up of many individual solar cells which in turn are made from thin wafers of silicon sandwiched together. Sunlight hitting these silicon cells provides the energy for electrons to move between the silicon layers and this flow of electrons is the electricity the panels produce. 

How does battery storage work?

Batteries allow you to store excess electricity generated when the sun is shining and use it at other times when you need it. Because the value of excess electricity that you sell back to the power grid (feed-in tariff) is generally lower than what you are charged when you consume electricity, it is more efficient to store your own energy for later use.

What happens to the energy I don’t use?

Excess solar power generally flows automatically back into the grid, or into a battery if one is installed. By reducing how much power you need to draw from the grid during the day, you can make big reductions in your power bill. Any extra power you produce will automatically be sold back to the grid, which further increases your savings. The value of the power sold back to the grid is credited to your electricity bill by your retailer, reducing your bill. 

What is the grid?

The grid refers to the network that transports power from generators (coal plants, solar and wind farms, hydro projects, etc), through the high-voltage transmission network (HV powerlines), then the low-voltage distribution network (street power poles) and to consumers (homes and businesses). 

Can I disconnect from the grid?

While it is possible to go completely off-grid, it is not the best solution for most homes. In periods of cloudy or rainy days, it is possible to deplete your energy supplies and you may find that you need to reconnect to the grid to sustain power to your home. Alternatively, you would need to invest in a very large solar and battery system that would be under-utilised for the majority of the time, producing significantly lower  savings than what it would cost to install.

Is solar worth it?

For most households, yes; systems pay for themselves in four to seven years and generally last 10 years or more. Still not convinced? Plug your average daily energy use and the number of panels you want into the RACV solar calculator to estimate the cost of a solar system and your potential annual savings – both financial and carbon.

How much will my electricity bills be with solar?

This depends on the system installed and how much energy you consume. Many households’ bills are more than halved, with ‘negative bills’ in summer that can leave your account in credit and help decrease winter bills as well. 

Solar panels on tiled roof
Electricians installing solar panels on roof

Make sure you choose a Clean Energy Council-approved solar retailer to install your home solar system.

How much does the average-sized solar system cost to install?

This depends on the size of your house, your energy consumption and the quality of the system. Basic solar systems can range from as little as $2000 after all the rebates, to tens of thousands of dollars for high-specification systems. High-spec systems will produce more power from the same number of panels and, importantly, last much longer than cheaper ones, meaning you can save for years and years into the future. The average price for a good system, after rebates, will be around $5000 to $7000.

How many solar panels do I need?

This depends on available roof space and household usage. A typical solar system would be about 15 to 20 panels. For more on the basics of solar, check out our beginner’s guide.

How long do solar panels last?

The panels themselves should last 10 years-plus, and often up to 20. Inverters probably won’t last as long – most have a five to 12-year warranty. 

What is the role of the solar inverter?

Solar panels generate electricity in the Direct Current (DC) form. The solar inverter converts the DC electricity to the Alternative Current (AC) form which can be used to power your home. 

Where can you buy solar systems?

Make sure you buy from a Clean Energy Council-approved solar retailer. Approved solar retailers adhere to a higher standard of ethical and compliant sales and marketing practices. If your system is installed by a non-accredited installer, you will not be eligible for the government rebates. RACV Solar is a CEC-approved retailer.

Who can install solar systems?

Panels can be legally installed only by an electrician, and they must be certified for solar in order for you to claim government incentives/rebates.

Do I need a battery?

Batteries provide several benefits, mainly around maximising the amount of solar power that can be used in the home, and most can provide protection from blackouts. Whether or not these benefits are worth the cost of battery installation is a case-by-case question for households. The price of batteries is likely to come down as they become more common, but for now, most households install solar panels without a battery. 

Can solar energy power everything in my home?

If the system is big enough then, yes, it can produce an equivalent amount of power to household consumption, and the power produced can be used by all electrical appliances in the home. However, panels produce power only when the sun is shining and so cannot power the home at night by themselves. 

Are there different types of solar panels?

Yes, there are many different technologies and brands.

Can you install solar panels on all roof materials?

RACV installs panels on tin, cement and terracotta roofs, but not slate. If your roof is made of a different material, speak to one of our solar experts.

My house isn’t north-facing. Does this matter?

In Australia, the best position for solar panels to face is north – but don’t stress if they can’t. It’s all about positioning them where they’ll get the maximum daily sun exposure. (These are a few more solar myths, debunked.)

How popular are rooftop solar systems in Australia?

Rooftop solar has been embraced so enthusiastically that we now have the highest penetration of residential rooftop solar in the world. Currently there are around 2.15 million Australian solar homes – and a growing uptake of battery storage.

Row of solar panels on pitched metal roof

Solar power is mainly generated in the middle of the day, so you’ll want to ensure that your roof is not heavily shaded when the sun is in its prime position.

Which are the best solar panels?

There are many good brands, but many more average and poor ones. Good solar panels should have a product warranty of 12 years or longer with efficiency higher than 310W. RACV uses only premium products and currently installs Winaico and LG panels. (While you’re at it, check out RACV Solar Package specifications to find out what’s included under warranty and what’s not.)

Am I eligible for solar rebates?

Yes. All solar systems installed by accredited installers and using approved products are eligible for the federal STC/LGC incentive scheme. The value of this incentive will depend on the size of the system, but is around $2000 for a typical-sized residential system. In Victoria, the most common solar rebates are applicable for households with incomes below $180k and a home value under $3 million, who have never had solar. Under the Victorian scheme, households can receive up to 50 per cent off the purchase price, capped at $2225. The majority of rebates claimed are for the full $2225. Read this article for more details on Victoria’s new solar rebates program.

Do solar systems need much maintenance?

Solar systems require very little maintenance. Rainwater will clean panels adequately in most cases and good-quality hardware, installed correctly, will last in the elements. Keeping an eye out for trees growing and shading panels or heavy dirt build-up is a good idea, and tree pruning or professional cleaning may be necessary in some cases.

I have an existing solar system but I’m not sure if it’s working. How can I check?

The easiest way to check is to look at the solar inverter (box on the wall). It should have some lights or a screen that you can check. Green lights are generally good and if the screen is showing power output the system is probably working. However, this is only confirmation the system has no major fault, not that it is performing well. Red lights or an error on the screen are signs of a problem. Another way to check is to look at your power bill to see if you are feeding in power. RACV also offers solar health checks

What happens if there is a blackout?

Australian standards require that grid-connected solar systems shut down in the case of a blackout. This is to prevent power flowing back into the grid and posing a risk to electrical workers who may be fixing the problem. Many newer battery systems can operate in a blackout by first “islanding” the whole system and the house from the grid.

Will my battery cover me in a blackout?

Many home batteries have blackout protection, but not all. In the case of a blackout, power to the home will be cut for around 30 seconds while the system recognises the blackout and switches to blackout mode. Back-up systems fall broadly into two categories: 

  1. Whole-of-home backup: where everything in the house can be powered in a back-up. The risk is that this will drain the battery quickly if the household continues to use large loads like air conditioners.
  2. Essential-load backup: when installing the battery, the electrician can isolate only certain circuits in the home to be protected in the blackout, to ensure things such as lighting and fridges can keep operating. This means the battery powers only these loads in a blackout, so as to maintain charge for much longer.

How long could a battery power my home?

Battery power varies depending on the type of unit and the amount of power you expect to draw from it. As a guide, a typical $10,000 battery being sold today will hold about 50 to 75 per cent of an average home’s daily electricity usage.

What are solar monitoring apps?

Solar monitoring apps – developed by inverter, battery or other hardware manufacturers – allow you to view solar energy produced on a daily, weekly and monthly basis. With additional hardware they can also show home energy consumed, excess energy exported, and energy stored in your battery (if installed). They are generally available on iOS, Android and web. They help you track your energy usage and show you how you are benefiting from solar and battery storage (if installed).

Is solar power sustainable?

From an energy source point of view, yes. The energy comes from the sun (which is a renewable source) and doesn’t contribute to global warming.

Electrician installing solar panels on roof
Solar panels installed on red-tiled roof

RACV Solar installs on tin, cement and terracotta roofs, but not slate. If your roof is made of a different material, speak to one of our solar experts.

Solar vocabulary

Green energy

Green energy can generally refer to any power generated from a renewable and/or non-carbon producing source. There is an official GreenPower registration scheme in Australia that has some additional requirements, partially around when the generator was built as this affects whether it is considered to contribute to emission reductions or not.

Renewable energy

This refers to energy that is generated by renewable (or natural) sources, such as solar, wind, hydroelectric and geothermal power. 

Clean Energy Council Solar Retailer Code of Conduct

This is a voluntary industry code, authorised by the ACCC, that is designed to lift quality higher than regulations require. 

STC/LGC incentive scheme

Refers to the Clean Energy Regulator’s small-scale technology certificicate (STC) and large-scale generation certificate (LGC). The Small-scale Renewable Energy Scheme creates a financial incentive for individuals and small businesses to install eligible small-scale renewable energy systems, such as solar panel systems (and also small-scale wind and hydro systems, solar water heaters and air-source heat pumps). It does this through the creation of small-scale technology certificates which Renewable Energy Target liable entities have a legal obligatio​​n to buy and surrender to the Clean Energy Regulator on a quarterly basis.​ Small-scale technology certificates can be created following the installation of an eligible system, and are calculated based on the amount of electricity a system produces or replaces (that is, electricity from non-renewable sources).

Solar batteries

Usually referred to as home batteries, these are devices that are capable of storing power to be used at another time. In a solar application, this allows extra power produced during the day to be saved for later instead of being sent back to the grid. That way at night, the home can be powered from stored power that was generated from the panels rather than importing power from the grid (which would include non-renewable generation). 

Solar optimiser

Solar optimisers are an optional accessory you can pay for when buying a solar system that helps to optimise the power output from each panel independently.

Reposit box

A controller for some home batteries that uses energy market data to identify times to export stored power directly to the grid when electrical spot prices are high.

Solar Feed-in Tariff (FiT)

The feed-in-tariff is a credit paid to households for excess energy that is sent back to the grid. This helps you ensure that excess solar energy produced by your panels is not going to waste and can help reduce your energy bills. As of 1 July 2019, the single-rate minimum feed-in tariff in Victoria is 12 cents per kilowatt hour (c/kWh).

Carbon offset

Carbon offset refers to the practice of reducing carbon emissions by an amount equivalent to emissions made in another activity. For example, I don’t want to contribute to global warming, but I need a car and can’t afford electric, so I work out how much carbon my car is producing and then pay to plant a number of trees that will capture the same amount of carbon from the atmosphere over their life as my car produces, thus offsetting the pollution. For more information visit Australia's Carbon Offset Project Registry