The Food Forest

Photovoltaic System

solar panels on houseThe system for the production of green electric power at The Food Forest comprises 30 thin-film amorphous silicon photovoltaic panels arrayed on the roof of the extension to the homestead.

  • The orientation of the roof is due north and roof pitch is approx 25 degrees in order to maximise the effectiveness of the modules
  • In this installation, the panels are also used to shade the northern roof face, which they virtually cover, reducing the need for super-insulation in the roof
  • Each panel nominally produces 58 Watts in ideal conditions
  • The total output is expected to beĀ  about 1700 Watts (1.7 kilowatts) in full summer sun
  • Power produced will reduce the CO2 greenhouse emissions from conventional power production by 3 tonnes per year

Amorphous panels maintain their output better than the mono or poly-crystalline ones when temperatures become extreme and operate better in low light situations, but the huge advantage is their low environmental cost. In fact the energy used to manufacture these panels is recouped within 2 years.


The SMA 1700E Grid Connect Inverter will convert up to 2200 Watts of direct current power from the photovoltaic system (which varies but is often approx 190 volts) into alternating current at a steady 240 volts of perfect sinewave power.

It is connected to the Mains grid via a meter which is capable of monitoring how much power is being exported from the photovoltaic system to the grid and, when the energy use of the house is greater than that being produced by the PV system, how much power is used from the grid.

A display panel on the inverter oscillates from readings of the power and voltage that the system is producing right now, to what the system has produced today and then to what the system has produced in its lifetime.

The inverter can be be linked to a computer for continuous logging and data interpretation.


The system was designed and supplied by Sandy Pulsford of Adelaide-based firm Solaris Technology, one of Australia's longest established photovoltaic and wind-power specialists.

Using the energy produced

See 'The Energy Efficient Home' fact sheet for details of how we make use of the system.