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Grid connect FAQ's

Solar power in its various forms can certainly be confusing if you're new to the world of renewable energy. Below are answers to common questions we see asked about solar power and residential grid connect systems.

solar power is the future!

General grid connect questions

What are the key historical dates in regards to solar energy?

1839 A. Becquerel discovers the principle of photovoltaic power generation.
1905 A. Einstein manages to make a scientific explanation of the principle.
1954 Bell Laboratories develops 1st silicon solar cell with an efficiency of 5 %
1955 Solar cells started to be used in space exploration.
1973 The oil crisis means that solar energy is seriously considered and promoted
1997 Australian photovoltaic research leads the world
2007 Germany has 1000 times more installed solar power systems than Australia thanks to their gross feed in tariff to fund the purchase of solar power systems.

What type of solar power systems are there?

There are two types of solar systems, stand-alone and grid connect. Grid connect systems, often located in built up areas, supply solar electricity through an inverter directly to the household or the electricity grid if the system is providing more energy than the house needs. Standalone systems usually operate in remote areas, away from power supply lines or where supply can be unreliable. The electricity generated by the system is usually stored in a battery bank consisting of deep cycle batteries which are suited for repeated partial charge and discharge.

What can affect the amount of solar energy received?

The strength of the solar energy (radiation) available depends on the time of year, the time of day, and the latitude of the generation point. The amount of energy generated can be further affected by the amount of dust and water vapour in the air, and the amount of cloud cover. You can learn more about solar radiation levels for your area in our solar power system builder.

What about cost?

Each system cost will be individually calculated by our solar system calculator according to your needs. Small solar power system costs start at around $ 4 000 after rebates and a system to provide most of the electricity for an average home can cost more than $30 000 for on-grid. There is currently a $8000 Federal Government rebate available for a 1kw system and a further Renewable Energy Certificate Rebate which is about $800 for a 1kw system.

What is a feed in tariff and how much will I get paid?

A feed in tariff is whereby a grid connect system owner is paid for the electricity their system generates by a utility or government agency. There are two different types of tariffs, gross and net. A gross feed in tariff pays a premium on all electricity produced whereas a net feed in tariff only pays on surplus energy created by the system. The amount paid is usually above market rate, up to 49c per kilowatt, but this varies from state to state. Learn more here

What size system will I need to run my home?

That entirely depends on your energy usage and your geographical location. A 1 kW system is currently the "entry point" for grid connect and attracts the most rebate per watt .It will cover between 16 and 25% of the energy consumption of a medium household. A 4 kW system will cover 100% of the energy consumption of a medium energy use household. Use our solar power system builder to calculate your energy needs.

Any size Grid Connect solar system will make in impact on your yearly power consumption and reduce your power bill. Naturally the bigger the system, the bigger the impact.

Our first advice is to use the available power most efficiently. It is easy to conserve energy by using appropriate lighting and efficient appliances. Running high power appliances such as electric bar heaters, electric hot water systems and air conditioners etc. is really not economical.

Instead of getting a bigger and bigger solar system it is advisable to invest in energy efficient heaters, solar hot water and design features such as strategically placed vents or insulation to avoid heat entering the house in the first place. In summary - all your energy can be supplied by solar power and your budget and daily energy usage will determine the size of your solar power system.

Is my building suitable to have a solar power system?

Several aspects will need to be evaluated to determine if your home is a good solar site, such as orientation, space available, shadows on the space available and your current electricity usage. The best site will be one with adequate north-facing roofs that have no shade. Variations on that will cut into the productivity of the system.

How long will my grid connect solar power system last?

Solar modules have been tested in the field showing small reductions in power output after 20 years, mostly because the glass surface becomes a bit dull and reflects more light. All our solar panels carry an output warranty of 25 years. There are now solar panels delivering power in Australia today, which were installed more that 30 years ago. Deep cycle batteries can last between 12-15 years, depending on correct system design and regular maintenance. The electronic components such as inverters, being the most sensitive, will last 10 -15 years. Learn more about the components Energy Matters uses in grid connect systems.

If my energy requirements increase, can I upgrade the system?

Yes. Additional solar panels can be added at any time to increase generating capability but you might have to upgrade to a larger inverter. Alternatively you could purchase a larger inverter when installing the system initially and then plan to add some extra solar panels later.

What happens on cloudy days?

In a grid connect system, as you are still tied to the mains power supply, any deficit will come from the mains grid.

How reliable will my system be?

As the Energy Matters systems are designed to Australian Standards, the reliability of components and consistency of power supply should be more than adequate for the loads specified.

Carbon dioxide emissions and climate change

What about the energy it takes to produce a solar power system?

Although solar electricity is pollution-free, PV systems require a certain amount of energy, which must be 'reimbursed' before they can be considered as renewable and clean. An assessment from the International Energy Agency concluded in mid 2006 that roof-top solar PV systems recover their energy content (from manufacturing and recycling) within 1.6 to 1.8 years in Australia.

Once they have reimbursed their initial energy input, roof-top PV systems can avoid the emission of 40 tonnes of CO2, depending on their location and on the local electricity mix available. Roof-top PV systems in Australia during their 30 year lifespan are expected to produce around 17 times the amount of energy needed for manufacture, installation and dismantling.

How much of a reduction in carbon dioxide emissions will I achieve?

CO2 discharge of cars is depending on the size of the engine. For example the Citroen C1 model has a CO2 discharge of 109 gram per kilometre and a Ferrari 559 with a 6 litre engine has a discharge of 490 gram per kilometre. Also the driving style can influence CO2 discharge significantly - by up to 25%.

The average vehicle in Australia travels 20 000 km per annum, which is equivalent to 3.3 tons of carbon dioxide discharge annually. A 2kw grid connected system will prevent 3.3 tons of carbon dioxide being generated through coal fired power generation - so it's the equivalent of taking a car off the road each year.

Solar power system components

What does a typical home solar power system consist of?

A simple grid connect system consists of a few solar modules and an inverter which converts the DC electricity into AC and is connected to the power grid through the electricity meter.

What is a solar module and what does it do?

A solar module, or solar panel, is a device which converts sunlight into direct current (DC) electricity. It produces electricity suitable for use in your home and for charging batteries.

Are there different types of modules?

Yes, there are various types of solar panels with different power ratings measured in Watts. Energy Matters has a range of solar modules that cater for a variety of applications.

Is there any maintenance involved?

With an on grid system (systems connected to the power lines) there is very little maintenance required. In a off-grid bush location regular maintenance of the batteries will increase their lifespan. Electronic components should be maintenance free. Energy Matters systems come with complete instructions for maintenance.

Electrical and installation

How can my system generate 240V AC?

This can be achieved by installing an inverter into the system. The inverter converts DC electricity into 240V AC. Solar systems are versatile and can be designed for both AC and DC, or can be converted at a later date. Solar systems can also be expanded to grow with your needs.

Is a solar regulator necessary in a grid connect system?

No, the inverter handles the incoming charge and converts it to AC electricity for use in your home

How does electricity get stored for use after the sun goes down?

Grid connect systems direct excess electricity produced during the day back into the local electricity grid. This turns your electricity meter backwards in the process. You then receive a credit for any power that your system supplied to the grid. During the night when your system does not produce and electricity you draw your power from the grid and your electricity meter measures your consumption.

What happens with grid connect systems during a blackout?

The grid connect inverter will automatically shut itself off within a few milliseconds of a blackout, to avoid the potential of a dangerous "brown-out" in your home and to prevent back feeding into the grid. Therefore even though you have a solar system during a blackout you will not have power available. If you want to keep on having electricity available during a blackout then you would need to have back up batteries installed as well, which will add to the cost of the system.

Can you retro-fit battery backup into a grid connect system?

Yes, battery backup systems require additional components similar to RAPS, such as, solar regulator, batteries, and inverter.

How does a solar system connect into current house power?

The solar system is wired into your existing fuse box via a 15amp circuit breaker.

Where do you place the inverter?

Usually the inverter is placed alongside fuse box. The inverter is silent and has a display to show the electricity generated and other data options eg total electricity generated since installation, are available.

What is the difference between solar panels (power) and solar hot water?

Solar panels take light from the sun and make electricity. Solar hot water systems take heat from the sun and heat water. It is easy to remember:

Heat from the sun heats the water.
Light from the sun turns on the lights.

How much roof space is needed?

1.0 KW system needs approximately 10m², 1.5KW system needs approximately 15m² and so forth.

What is the weight of the solar system on the roof?

The system weighs approximately 27 kilograms per square meter (a 1KW system is approximately 10 square meters).

How does a solar power system work?

Solar power systems convert the energy from sunlight into direct current (d.c.) electricity. An inverter then converts this direct current to alternating current (a.c.), to make it compatible with grid electricity. Solar power systems should be oriented to the North and tilted in order to generate as much electricity from the sun as possible. Learn more about how grid connect solar works.