Grid connect FAQ's

Below are answers to common questions we see asked about solar power in relation to residential grid connect systems.

What is a grid connect solar power system?
Grid connect systems, often located in built up areas, supply solar electricity through an inverter directly to the household and to the electricity grid if the system is providing more energy than the house needs. When power is supplied to the mains grid, the home owner usually receives a credit or a payment for that electricity. This is called a feed in tariff.

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, the amount of cloud cover and any shading of the solar panels. You can learn more about solar radiation levels for your area in our solar power system builder.

Does roof orientation really matter?
Most certainly. For example, a system with solar panels facing in a westerly direction will generate far less than one with a northerly aspect.

How much does a grid connect solar power setup cost?
1.5kW. Small solar power system costs start at around $ 4000 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 ar Renewable Energy Certificate (REC) rebate which is approximately $5000 for a .5kw 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.

What size system will I need to run my home?
That entirely depends on your energy usage and your geographical location. A 1.5 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 4-5 kW system will cover 100% of the energy consumption of a medium energy use household. Any size grid connect solar power system will reduce your yearly power consumption and your power bill. Naturally the bigger the system, the bigger the benefit.

To make the most of solar power, the key is to implement simple energy efficiency strategies. 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 considering a very large 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 for 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 solar panels delivering power in Australia today that were installed more that 30 years ago. 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.

What type of warranty is supplied with the system?
Solar Panels: 20 - 25-year warranty to produce 80% of rated output (manufacturer)
Inverter: 5-year warranty. Can be extended to 10 years for an additional charge (manufacturer)
Mounting System: 10-year product warranty (manufacturer)
Workmanship: 5 year warranty on workmanship (installer)

Should I choose monocrystalline, thin film or polycrystalline solar panels?
Between monocrystalline and polycrystalline there isn't a lot of difference except that a polycrystalline panel is slightly larger than the equivalent wattage in monocrystalline. However, that extra space can take up valuable rooftop real estate in terms of adding extra panels at a later date. Thin film panels are larger again and there are other issues to consider, explained in further detail here. We generally recommend monocrystalline for grid connect situations.

What can affect the costs of installing a grid connect system?
A base installation rate includes the grid connect system being installed on a pitched metal roof facing north with appropriate surface area available. Additional costs will be incurred for a flat or tiled roof; any equipment upgrades and extended warranties.

Can I insure my grid connect system?
Most insurers will allow you to include the system under your home and contents insurance, but please check with your insurance company first.

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 Solarwind systems are designed to Australian Standards, the reliability of components and consistency of power supply will 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. This is known as "embodied energy". 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?
Using a comparison to a car, 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. The inverter is connected to the power grid through the electricity meter.

Is there any maintenance involved?
With an grid connected system, there is very little maintenance required.Electronic components should be maintenance free. Energy Matters systems come with complete instructions for maintenance.

Electrical and installation

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 - a solar regulator and batteries.

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 such as total electricity generated since installation, are available.

What is the difference between solar 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 to DC curent then ACin the inverter to turn on the lights.

How much roof space is needed?
1.0 KW system needs approximately 10m2, a 1.5KW system needs approximately 15m2 and so forth.But different panels have high output for the same size

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).