Home > Feed-In Mechanism/Further Informationl

Further Information

• Metering of PV Systems
• The Distributor Model in More Detail

Metering of PV Systems

The output of the photovoltaic (PV) system is connected to the household loads which in turn are connected to the grid via a bi-directional or ‘import/export meter’. When the output of the PV system exceeds the household loads, the excess electricity is fed into the grid via the ‘export’ register of the meter. The meter records the ‘net export’ rather than the ‘gross production’ of the PV system (ie gross production – household load = net export).

When household loads exceed the output of the PV system, the balance of electricity required is taken from the grid via the ‘import’ register of the meter (ie household load – gross production = electricity purchased).

Once per quarter, both the import and export registers are read and this information passed to the responsible retailer. Net exports (ie electricity returned to the grid), typically vary from 10 per cent to 50 per cent of the total production of the panels* for the billing period depending mainly on household electricity consumption patterns and the size of the PV system. If 50 per cent of panel gross production is returned to the grid, this is equivalent to around 20 per cent of the average household’s electricity consumption.

The following energy flows for a ‘typical’ household consuming 5,000kWh per year, with a 1.5kW PV system returning 50 per cent of production to the grid illustrates how the PV system not only produces ‘export’ electricity but, for a given level of household consumption, reduces the household’s electricity demand from the grid.

* Based on ETSA Utilities provided metering data

A simplified example

In this case, the annual return on the investment can be summarised as below:

Before installing PV : 5000kWh at an average 20c/kWh = $1,000 per annum

With Feed-in : 4000kWh at an average 20c/kWh = $800, less;1000 kWh at a minimum 44c/kWh = $440, leaving a net bill of $360 per annum. In this case, the household reduces their electricity bills by $640 per annum.

Note that each individual customer’s circumstances will differ and that this saving may not apply in each case.

The Distributor Model in More Detail

The model chosen for the operation of the feed-in scheme is a distributor-based model, developed as a result of the consultation that was carried out in 2007.

The main changes that were made since the 2007 consultation are:

• The scheme has been upgraded to a 20 year scheme;
• Eligible customers have been expanded to include all ‘small’ customers which will now include small businesses and community facilities that consume less than 160 MWh of electricity per annum;
• In the interest of simplicity, no changes to market reconciliation of electricity exported from solar PV systems has been made. Electricity retailers continue to receive the excess electricity from their customers and are encouraged to offer a market value for that electricity in addition to the feed-in premium.

Click here to view the original consultation paper (PDF 374KB).

Return to main feed-in page

Return to Frequently Asked Questions page

Return to Top