Solar power for home — frequently asked questions
What are solar panels?
A photovoltaic (PV) module is a packaged interconnected assembly of photovoltaic cells, also known as solar cells. An installation of photovoltaic modules or panels is known as a photovoltaic array. Photovoltaic cells typically require protection from the environment. For cost and practicality reasons a number of cells are connected electrically and packaged in a photovoltaic module, while a collection of these modules that are mechanically fastened together, wired, and designed to be a field-installable unit, usually with a glass covering and a frame and backing made of metal, plastic or fiberglass, are known as a photovoltaic panel or simply solar panel.
A typical solar panel is 0.5m wide x 1.2m long and generates approximately 80 watts of power under full sunlight however the nominal output from newer panels is increasing as PV technology matures.
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Can I have solar panels on my roof?
To have solar panels on your roof there are a few things you need to consider first:
- Solar power systems should be orientated north and tilted to generate as much electricity as possible
- Some local authorities insist on planning permission, especially in conservation areas or listed buildings
- Space – is their sufficient space available to site your panels; and
- Strength – is your roof strength sufficient to support your panels (most truss roofs are strong enough).
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What does a typical home grid-connect solar power system consist of?
Solar panels provide direct current (DC). Domestic PV systems use an inverter to convert DC current from the panels into standard 240V 50Hz AC current suitable for use in the home and for exporting to the grid. An additional meter is required to meter the output from your PV array.
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Will I need a new meter and if so who pays for it?
Yes. Two meters are used for this type of connection. The first meter measures electricity supplied from the grid to your home (your existing meter), and a second meter will measure electricity supplied by your PV array back to the grid.
ActewAGL may (i) simply add a second meter to compliment your existing meter or (ii) replace your old meter with a new dual register meter. Either way, this is done at ActewAGL's expense with no charge to the customer.
Customers are responsible for ensuring adequate space to accommodate the new metering arrangement in their meter box. Most existing meter boxes are fine but smaller ones may need to be upgraded – at the customer's expense.
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What happens to the electricity in my house?
During the day when the sun is shining, your house is supplied from your PV array with any excess electricity exported to ActewAGL's distribution network. At night when the sun is no longer shining, your electricity is supplied as usual via ActewAGL's distribution network.
By connecting your PV array to the grid, ActewAGL’s distribution network acts like a large battery, allowing you to store your surplus electricity during the day to then draw from during the night.
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How much energy will I be able to produce?
This depends on a number of factors. The most significant factor being the size of your system, referred to as the installed capacity. Other important factors that affect the output include:
- Location
- Orientation
- Maintenance (are your panels cleaned regularly?)
A typical energy efficient family home in Canberra uses between 15 and 20 kilowatt hours per day, or 5,500 to 7,500 kWh per year. Modest homes using natural gas for hot water, heating and cooking tends to use even less at around 4,000 kWh per year.
In Canberra, under good conditions, the expected output from a range of system sizes is tabled below:
Installed capacity
(kilowatts) | Generated output ACT
(kilowatt hours) |
| 1.0 | 2048 |
| 1.5 | 3072 |
| 2.0 | 4096 |
| 2.5 | 5120 |
| 3.0 | 6144 |
| 3.5 | 7168 |
| 4.0 | 8192 |
| 4.5 | 9216 |
| 5.0 | 10240 |
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How much money will I need to spend?
While the running costs of PV generation are virtually zero (the fuel, sunshine is free), they do have very high set-up costs. A small 1kW system that generates approximately 2,000 kWhs of electricity annually costs approximately $15,000 installed. Please note however that the final cost of this system would be $7,000 after collecting the $8,000 government rebate.
Approximate installed costs for a range of system sizes is presented below:
Installed capacity
(kilowatts) | Approximate Installed
Cost |
| 1.0 | $13,500 |
| 1.5 | $18,600 |
| 2.0 | $22,600 |
| 2.5 | $27,600 |
| 3.0 | $33,100 |
| 3.5 | $38,600 |
| 4.0 | $44,100 |
| 4.5 | $49,600 |
| 5.0 | $55,100 |
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What rebates are available?
Australian Greenhouse Office – Photovoltaic Rebate Programme (PVRP)
Photovoltaic systems convert sunlight into electricity. Under the photovoltaic Rebate programme (PVRP) which commenced on 1 January 2000, cash rebates are available to householders, owners of community use buildings, display home builders and housing estate developers who install grid-connected or stand-alone photovoltaic systems (conditions apply)
As of May 8, 2007, the rebate level for new systems is now $8 per peek watt, capped at $8,000 per residential system. The new competitive grants element of the programme will enable schools and community groups to apply for a grant of up to 50% of the cost of a solar power system, with an upper limit of 2 kilowatts.
Under the 2008-09 Federal Budget the government has introduced a means test, households with an annual taxable income of less than $100,000 eligible for the rebates.
To be eligible for the PRVP rebate, your PV system must be designed/installed by persons accredited to do so with the Business Council of Sustainable Energy (BCSE accreditation).
More information about the PVRP program
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How do ActewAGL's buy-back arrangements work?
The operation of ActewAGL's 'Domestic Solar Generation' tariff as published in ActewAGL's 'Standard retail electricity supply - Schedule of charges from 1 July 2007' is summarised below.
- Customer continues to pay supply charge - because the customer still accesses electricity from the grid.
-
If customer is a net importer - a full retail value offset is offered for electricity exported into the grid by the customers system.
e.g. if in a billing cycle the customer imports 2000 kWh and exports 1000 kWh
- Net = 2000 imported - 1000 exported = 1000 imported
- Customer is billed for the net amount imported, 1000 kWh
Note
This means the customer is effectively credited with the full retail value of the 1000 kWhs they generated. The customer receives a bill from ActewAGL for the net amount imported.
-
If customer is a net exporter - 7.4c/kWh is offered for electricity exported into the grid.
e.g. if in a billing cycle the customer imports 2000 kWh and exports 3000 kWh
- Net = 2000 imported - 3000 exported = 1000 exported
- Customer is credited for the net amount exported, 1000 kWh @ 7.4 c/kWh = $0.074 x 1000 = $74.00
Note 1
This means the customer is paid 7.4 c/kWh for the net electricity they generated. The customer receives a cheque in the mail from ActewAGL for this amount (minus the supply charge - see point 1). Direct debit/credit facility is also available for convenience.
Note 2
If the net export is small, the credit might not be enough to cover the supply charge so the customer will receive a bill from ActewAGL.
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Why do ActewAGL pay 7.4c/kWh for net exports when you charge more for imports?
ActewAGL's buyback policy provides '1 for 1' credit for electricity supplied by your PV array against electricity drawn from the grid. The lower rate of 7.4c/kWh applies only to ‘net exports’ during a billing period, that is, only when you become a net supplier of electricity to ActewAGL.
ActewAGL operates in a competitive retail environment. ActewAGL purchase electricity from the wholesale electricity market and provide this for sale to our retail customers.
Although the energy component of the retail price is the largest, the regulated retail price at which ActewAGL sells electricity includes other charges in addition to the wholesale cost of electricity, network fees being the most significant. Network fees cover the costs of maintaining a reliable distribution network (the poles and wires delivering electricity to your house). Network fees are government regulated and are payable by all retailers using the ActewAGL distribution network. ActewAGL's own retail arm pay the exact same fees to use the network, as do our competitors.
State and Federal governments levy environmental charges (GGAS, MRET) that are also included within the regulated retail price for electricity.
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I want PVs installed - who in Canberra can do this?
ActewAGL can't promote any individual installer. A current list of accredited installers is available at the BCSE website.
Alternatively, see Yellow Pages "Solar energy equipment" to pick up local installers.
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I've selected my preferred supplier/ installer, what do I do now?
- Your chosen installer will select/design a PV system to meet your requirements.
- Your installer will return to ActewAGL Networks Division, several completed forms to arrange for new metering. One of these is a completed copy of the ‘Request for Special connection, Service and Installation Rules, Supplementary Section S19’ form. You are required to sign this form once completed.
-
ActewAGL's Networks use information from this form to assess whether your system is compatible for connection with the grid.
Important information collected via this form:
- Customer Information – your name, address & ActewAGL electricity account number.
- System Information – system size (nominal output), inverter and panel details & line diagram of the proposed installation.
- Installer Information – installer name, company & license number.
- Customer Declaration – customer signature declaring accuracy of information provided.
- ActewAGL Networks process the form and once approved arrange to meet your installer's electrician on-site at your home to install your second electricity meter.
- ActewAGL Networks notify ActewAGL Retail of successful installation of the second meter.
- ActewAGL Retail switch the customer to the ‘Domestic Solar Generation' tariff as published in ActewAGL's 'Standard retail electricity supply - Schedule of charges from 1 July 2007'.
- Your installer completes your PV installation.
- Your next ActewAGL electricity invoice now records both exported and imported electricity.
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