Solar PV Explained

Want to know what Solar PV is, whether it's right for you and what's involved in buying and owning a Solar PV system?

Read on to find all the information you need about:

For more information, you can also download our Alice Solar City Solar PV fact sheet

What is solar PV?

 A solar photovoltaic (PV) power system is a technology that converts the energy from sunlight into electrical energy.  Residential PV systems can meet some or all of a household's power needs, depending on the size of system and the household's needs.

In a typical system, a set of photovoltaic modules, or 'solar panels', are installed on the roof of your home, and the energy generated by these panels is passed through an inverter which creates electricity to match that coming in from Power and Water Corporation. A residential PV system can meet some or all of a household's power, depending on the size of the system and the household's needs.

In a typical system, a set of photovoltaic modules, or 'solar panels', are installed on the roof of your home. When the sun hits the panels, electrical current is generated (as DC) and fed to the inverter, which produces electricity at 240 volt AC (the same as the electricity grid). This electricity then feeds into your local electricity network via the electricity meter. The meter records the amount of electricity produced, and this information is used by Power and Water to provide a credit on your power bill.  The amount of electricity produced by a system (measured in kilowatt hours (KWh) is directly related to the capacity of the system installed. The amount of available roof space can limit the size of the system installed. Other factors can also affect generation.

More electricity is generated when:

  • The panels directly face the sun;
  •  The weather is cool and sunny;
  •  The days are longer.

Less electricity is generated when:

  • The panels are shaded (by trees or nearby structures, for example);
  • The weather is cloudy or rainy;
  • The panels have an accumulation of dust or other debris.
  • Roof orientation and pitch are not optimal

In remote areas solar PV systems rely on batteries to store energy so it can be used later; in urban settings like Alice Springs, systems don't use batteries and are instead connected to the electricity grid. By installing a grid connected solar PV system and entering into agreements with Power and Water Corporation (PWC) households become, in effect, mini power stations selling all of the electricity generated to PWC (see Power and Water Corporation website for feed-in tariff rates). 

PV systems should not be confused with solar hot water systems, which are sometimes also referred to as 'solar panels'. In a solar hot water system, panels on your roof use the sun's energy to heat a fluid which then heats your hot water.

 

Why install a solar PV system?

 There are many reasons to have a PV system installed.

  • You will be generating clean, renewable energy.
  • You will save on your power costs as the PV system will meet some - or all - of your power needs.
  • The electricity generated by your PV system can be sold to PWC for a credit on your power bill (subject to entering into the necessary standard agreements with PWC).
  • Because solar power is generated during the day when the community's power demands are typically at their highest, your investment may help delay the need for expensive upgrades to our energy infrastructure.
  • The value of your home may be increased as demand for sustainability features in homes increases.

 

Can I supply all of my electricity needs from a solar PV system?

The answer to this question will depend on how much electricity you use and what size solar PV system you are able to install.

As a general rule of thumb, a 1kW solar power system (typically 5 or 6 panels), installed on a roof with the optimal orientation, pitch and minimal shading, could produce around 1,600 kWh/year. The average Alice Springs household uses about 8,500 kWh/year.

Connection to the grid is also subject to approval by the electricity network operator. As the amount of solar PV on the network increases, particularly in residential areas where solar power doesn’t always match household consumption, it becomes harder (and more expensive) for utilities like Power and Water to balance the network to ensure reliable and safe electrical supply.

You should therefore ensure that your preferred installer receives approval from PWC for your proposed solar PV installation before you place an order.

When installing a solar PV system, it makes sense to also look for opportunities to improve your energy efficiency. Using solar water heating, buying efficient appliances, and ensuring that your home's air-conditioning needs are low are key ways to reduce your electricity use, and are typically more cost effective than buying a larger solar power system.

 

What do I get paid for the power I generate?

The price you are paid for the power you generate will depend on the buyback rate or feed-in tariff in place. Most household solar PV installs in Alice Springs have the metering set up so that all the power you generate is recorded separately from the power you consume, so that on your bill you will see your total consumption separate from your total generation.

Households who installed a BP Solar system through the Alice Solar City PV incentive program: The elevated buyback ended on 31 May 2013. Customers will need to complete Power Purchasing and Network connection agreememts and lodge with Power and Water.  If you installled a  BP PV system through the Alice Solar City residential incentive program and have not already filled in these documents you should contact Power and Water on 1800 245 092.  From 1 June 2013 the tariff rate for these systems will be in line with the normal buyback tariff which can be viewed on the the Power and Water website.

Installations done outside of our residential PV incentive program: The current buyback tariff may be obtained from the Power and Water website.

 

Rebates and incentives

Australia wide funding mechanisms are available to Alice Springs residents, and with the continued reduction in the price of solar panels, along with the increase in competition, householders can access very competitive solar power systems starting from around $4,000.

Small Scale Renewable Energy Scheme (SRES)

Under this scheme, Australian households installing a small scale renewable energy system (such as a solar PV system) are eligible to claim a specific number of Small-scale Technology Certificates (STCs). STCs are a tradeable commodity and may placed and sold on the STC market (to the likes of Power & Water Corporation), sold via the STC Clearing House for a fixed price of $40 per STC (excluding GST), or assigned to agents, usually PV system suppliers in exchange for an up-front discount on the price of the PV system.

The number of STCs generated by a solar PV system is determined by the capacity of the system, its rated output, the postcode/zone in which it is located and a deeming period, which is an estimate of the number of years the system will generate renewable energy (the average expected life of the system). In most cases, the maximum deeming period of 15 years is claimed upfront, but claims can be placed every five years, or even every year. The deeming period eligible to claim for may be subject to change in the future.

Example: STC calculation for a 1.5kW PV system installed in Alice Springs (zone 1, rating 1.622MWh/year) with a deeming period of 15 years:  

    
       1.622                  x 1.5                            x 15                          = 36.5 (rounded down to 36) STCs created
 ZONE RATING    SYSTEM SIZE           DEEMING PERIOD   

Calculators designed to provide an estimate of the number of Small-scale Technology Certificates (STCs) which may be created in relation to an installation can be found online at the Office of the Clean Energy Regulator website.

 

Do I need a Building Permit?

No. In April 2011, the NT Government's Building Advisory Committee released a policy that exempted solar PV systems from requiring a Building Permit in non-cyclonic areas. However, an inspection of your roof is required to be undertaken before the solar PV system is installed (by a structural engineer, building certifier or building contractor) - in most cases, the costs for this inspection should be only a few hundred dollars. The exception is if a building permit for the house was issued within 5 years of the proposed installation, in which case no further inspections are required.

 

What laws and regulations apply to Solar PV

Installation of a grid connected solar PV system is covered by a range of standards, laws and requirements.

Connection of solar PV to the electricity network in the Northern Territory must be approved by and meet the requirements of the Power and Water Corporation

Installation of a solar PV system must be carried out by a qualified electrician who is accredited with the Clean Energy Council of Australia.

Northern Territory building regulations also apply in relation to the building structure the PV system is being installed on.

A number of Australian Standards cover the installation of solar PV. In addition to the general electrical standards, there are two relating specifically to solar PV: AS 4777 "Grid Connection of energy systems by inverters" and AS/NZS 5033 "Installation of PV Arrays".

 

More information

We have summarised the essentials of solar PV on our fact sheet here.

You can also read more about rooftop solar power at these websites: