FAQ Solar Power Systems

FAQ Solar Power Systems

some Important solar facts to get you started..

  • Most councils will require approval for systems over 10kW
  • Systems over 30kW will require approval, in writing from the network. This approval may come with conditions which might be expensive to meet
  • 99 kW systems often present the best value, as 100 kW is the threshold where small scale credits can't be claimed upfront as a capital offset, and instead have to be claimed at the end of the financial year they are generated 
  • Buying a solar system which includes solar energy generation monitoring and solar energy consumption monitoring will enable you to have the best quality information for optimising your solar power system
  • Ground mount systems can often require more cost and planning than roof-mounted systems



What are kW, kWh & PV?

kW: kilowatt, or 1000 watts. This is a measure of power. 

kWh: kilowatt hour. This is a measure of energy. For example if you use a 1kW electric device for 1 hour, it will consume 1kW/h of electricity.

PV: PV just means photovoltaic, which is the technology that enables sunlight to be turned into electricity. All solar power systems available in Australia are PV.

The difference between different solar panels: solar panels are categorised based on the amount of PV ‘cells’. Residential solar panels will often have 60 cell panels, whereas larger commercial operations will often have larger and more powerful 72 cell panels.

How is the kW rating of a solar power system determined?

Each solar power system is rated based on the maximum amount of watts it can produce each hour. This is determined by the number and type of panels. For example a system with 12 x 260 Watt panels would be a 3.12kW system (or 3120 Watts).

What is a commercial- sized solar system?

Any solar power system above 10kW (for context; 6kW is around 20 panels).

There are three categories of commercial systems:

Less than 30 kW: same hardware required as residential systems and same rules when it comes to connecting to the grid. Subsidies will be delivered through STC program.

For context; a 30kW system will generate 120 kW electricity per day.

30-100 kW: special system required to connect to grid and special permission needed from your local electricity network. A commercial system specialist will be required. Subsidies will be delivered through STC program.

Over 100 kW: as above, a commercial specialist will be required. Over 100kW STCs are not offered, instead subsidies will be delivered through LGC, Large-scale Generation Certificate.

What are the different subsidy schemes?

STC Program (or rebate): stands for small scale technology certificate. This is the subsidy provided by the federal government for installations under 100kW. This rebate is usually applied at the point of sale. The STC price can be reduced at any time as it is designed to respond to the demand for solar in the market. The maximum STC price is $40, and the minimum $0. At the moment its about $37. The amount of rebate you can claim also varies depending on your location.

In order to qualify for the STC program you need to; install a system smaller than 100kW, have your system installed by a Clean Energy Council accredited professional and use solar panels and inverters that are approved for use by the council, too.

Feed in Tariff: this is the payment received (or credit) from your electricity provider for excess electricity that is fed back onto the grid. The price of this is set by each state government. Available for every system size, but not from every electricity provider. 

LGC: LGCs are created once per year, based on the MWhs (mega watt hours) of electricity created and exported back to the grid. As with STC program, the price for LGCs also fluctuates. To be eligible to receive LGCs you must comply with all federal, state and local government planning and approval laws and become an ‘accredited power station’ with the Clean Energy Regulator. You must use NEM (national energy market) or approved metering that enables the Clean Energy Regulator to accurately determine the amount of electricity generated.

What are inverters?

Inverters are necessary for solar power systems. They convert the DC output of solar panels into AC power which can be fed into the grid and home.

There are three options for inverters appropriate for a commercial solar power system:

Microinverters and optimisers: small inverters attached to each solar panel. They are more expensive but offer performance and safety benefits.

String inverters: are connected to a string of solar panels, usually these will be located between the panels and the switchboard.

Large central inverters: one large inverter which services the whole system. Can be very large and therefore difficult to manoeuvre. Present a risk as one failure may cripple entire system.

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