Our original home was not really self-sufficient as it had energy inputs of gas, petrol and firewood as well as wind and solar. Rather than aiming at any theoretical self-sufficiency when the house was being built in 1980 the restricting factor was finance. The design was basic – a rectangle with veranda all around – and cheap with walls of mud and beer bottles, second hand windows and doors. Construction proceeded as, and when, finance became available. The cost to get grid electricity to the house site was impossibly high. The quote from the SEC to do so was $15,000. So the decision was made to set up a ‘stand-alone’ power system. Eventually the whole house, including the original power system, was built for the same amount as that SEC quote.
Incorporated in the design were a number of simple energy systems. Some worked and some didn’t. The hot house on the north-west and shade house on south-east were meant to provide passive warmth in winter and cooling in summer. The latter was never completed and the hot house only functioned during the last few years of our residence. When used for propagating trees it added a degree or two of warmth to the house in winter. Initially the power system was a reconditioned 300w wind generator with 12v/240v wiring and a petrol generator back up. Solar was far too expensive at this stage. Cooking was via gas stove in summer and woodstove in winter which also provided hot water. The refrigerator was also gas powered. In 1986 we purchased our first solar panels (2 X 30 watt at about $800) and solar hot water was installed to compliment the wood stove. By 2000 the wind generator, after 18 years of reliable service but in need of substantial maintenance, was mothballed and replaced by a further six 80 watt panels of solar.
The biggest weakness in the house was the cooling system. With only a small gap and foil insulation in the iron roof the house tended to retain its heat. For most of the time this did not matter as with natural cooling by night and with regular late afternoon cool changes in summer it was only a matter of opening a few windows. To cope with any heat build-up we only had 2 small portable fans. The 2009 heatwave that preceded Black Saturday meant that the inside house temperatures eventually built up to over 30 degrees at 6am. The response to this was to have reflective paint put on the previously unpainted roof the following season. This had the desired effect of lowering inside temperatures by about 5 degrees.
For 30 years we had a low capital cost but high maintenance house and energy systems. There was regular checking of batteries, occasionally running a petrol generator, buying (or collecting) firewood and gas for fridge and stove. I have estimated the running costs for the house over 30 years – for gas, petrol, firewood at $10,000 or about $330 pa. The capital costs including the original system, replacement petrol generator and batteries (second-hand) solar hot water and 2 lots of solar photovoltaic panels (the second lot subsidised) eventually totalled about the same as the original SEC quote or about $500pa. Considering our financial restraints I think this can be considered a successful experiment tending towards self-sufficiency.