OK, I am going to collate the facts, my facts about domestic solar power production…
1) COST: paid on 13 June 2012 = 10,435.50
2) Warranty on parts and potential failure due to factory fault = 10 years
3) Looking at my quarterly bill dated 27 Dec 2013 shows: a) I am paying a basic tariff of 0.2630 per kWh, b) + service fee of 0.50219 per day x 91 days, c) + 33.33 GST for 91 day total charge of AUD$366.64.
4) Looking at my quarterly bill dated 27 Dec 2013 shows: a) I am being paid a basic feed-in tariff of 0.4400 per kWh, b) + a “special” fee-in tariff of .3000 per kWh, c) for a total subsidy of AUD$553.52.
5) So I am paying 0.30977 per kWh; while being paid 0.7400 per kWh fed back into the system.
6) Since I paid for the system in June 2012 my bill tells me I have accumulated a total credit to-date of 438.14 or, a value accumulated at an average of AUD$24.34 per month.
7) My bill tells me usage is averaging a very reasonable 11.82 kWh per day.
8) My bill tells me I am averaging a feed-in of 8.22 kWh per day.
So, after 10 years, the system remains unpaid for, at current rates of cost, usage and feed-in credits.
Of course, of course, send this into a 20 year amortization table, of course, it’ll work. But my limited warranty is 10 years, so, perhaps I should stick to the facts and not dream here.
Finally: These number show that a 3kW photovoltaic collection system will not produce enough for an average daily use of 12kWh. If I indeed wished to become self-sufficient I would have to invest in more collection capacity – AND – batteries. Without a way to store the power produced you don;t have power unless the collection system is collecting so… without even sucking my thumb and testing the wind…
Domestic solar collection systems simply do not pay, AND, really are only even close to being viable if, IF, big subsidies are paid to entice people to invest in this “GREEN” technology. I note that when (not if) the feed-in credits are cancelled the system on my roof becomes an expense and is of very little real benefit or gain to me, in the long-term.