Solar PV panels on the roofs of homes and businesses generate clean electricity by converting the energy in sunlight. This conversion takes place within modules of specially fabricated materials that make up the solar panels. It is a relatively simple process that requires no moving parts. In most cases solar panels are connected to the mains power supply through a device called an inverter.
Solar panels are different to solar hot water systems, which are also mounted on household roof-tops but use the heat from the sun to provide hot water for household uses.
Most suburban homes in Australia are connected to the electricity grid, which uses alternating current electricity (AC). But the electricity generated by solar panels is direct current (DC). That means grid-connected (GC) solar PV systems need an inverter to transform the DC electricity into AC electricity suitable for ordinary household needs. Houses with solar systems use solar power first before sourcing electricity from the grid.
When the panels are not producing electricity at night, electricity is supplied from the existing electricity grid. For systems with a battery backup (optional), the inverter regulates the charge of batteries. The electricity stored in the batteries can be used at night or during blackouts.
What happens after my solar PV system has been installed?
Entering into agreement with your electricity retailer: After your solar PV system has been installed and if you wish to opt-in to a feed-in tariff, you will need to
enter into an agreement with an electricity retailer. Not all electricity retailers offer solar friendly policies
so it is best to check and compare the following items prior to entering into an electricity trading
agreement. Please contact your electricity retailer i.e origin, AGL, ergon and create business-tobusiness
agreement for feed-in-tariff.
Questions to ask your electricity retailer
- What price will they pay you for your electricity (in cents per kWh)?
- What is the cost of the electricity you purchase from them (in cents per kWh)?
- Will I lose my off-peak rates once my meter has been changed?
- Will this be replaced with a time-of-use (TOU) tariff?
- Are you signed onto a premium feed-in tariff rate or a standard feed-in tariff rate? If your electricity retailer signs you up to a standard feed-in tariff agreement you will receive less money for the excess electricity you feed back into the grid.
- What will be the form of payment for electricity you produce? It is likely you will receive the feed in tariff’s you earn by default as a credit on your electricity bill rather than cash.
- What will be the form of payment for surplus electricity you produce? Will it be cash, cheque or EFT on request?
- Penalty clauses (termination costs)
- Billing / payment periods
- Are there any other administration fees?
- Do you organise all the necessary metering changes
What will happen to my meter at home?
When your solar PV system is installed you may need to have a new meter installed. If you have a traditional accumulation meter (with a spinning disk) this will need to be replaced with an interval meter or smart meter. This is because an accumulation meter does not record the energy you export to the grid or the electricity you import from the grid. An interval meter or a smart meter provide half hourly readings of the electricity you consume and the surplus electricity you generate.
The states and territories have committed to the progressive rollout of smart metering across Australia from 2007. While a smart meter is similar to an interval meter in that it records electricity usage in 30-minute intervals remotely to your electricity company, smart meters have a range of additional capabilities. So if your new meter is an interval meter, it will need to be replaced again with a smart meter when this rollout occurs.
Depending on where you live, your interval meter may be a gross meter or a net meter. If you are on a gross feed-in tariff scheme, your gross meter separately
measures the total electricity consumed by your household and the total electricity generated by your solar PV system. Your electricity company reads the meter and determines the total amount of electricity generated by your solar panels, regardless of whether it goes into the grid or is used by your household.
If you are on a net feed-in tariff scheme, your net meter measures your household’s electricity and the electricity generated by your solar PV system together. Your electricity company reads the meter and calculates any surplus electricity fed back into the grid. Your new meter must be installed by a relevant qualified professional. This may be organized by your accredited designer/installer; or your electricity retailer; or electricity distributor. Ask to find out who will organise this for you.