After discovering the realities of how retailers can gouge solar owners regarding pricing, and seeing a few reviews on the net whereby the net savings by consumers were reported in the very small numbers of dollars per billing cycle, a message is that adding solar may not always be smart for the pocketbook.
The poor payback will be from solar systems that offset but barely or do not cover the household’s ‘prime time’ consumption. If you install a ‘too small’ solar system, as a contrived example consider one that can only produce 2.5 kw per day average generation but the average consumption is 5 kw per day that is mostly during peak hours (0700-2300 M-F in Vic). You will be paying a peak retail rate for solar that could be near double your pre-solar rate, and you will pay from about 2 to 4 times more for consumption than they will pay you for your feed-in. The off peak rates are reduced although still more than your feed-in rate, but can you do all your laundry and dishwasher, run your A/C or heat if you have any and when needed, and do all the electric fuelled cooking off-peak, to make that point?
Simplistically even if you import half as much power from the grid after adding solar, you could pay about the same on your bill unless your system usually supplies ‘all and then some’ of your typical consumption. nb. My new system is generating from more to far more than consumed between 0900-1800 when the panels are doing their best, but 0700-0900 and 1800-2300 can blow the budget.
In Vic there is a max 5KW limit (AC feed-in to the grid) that would be about 17~20 microinverters and panels, or 6.5KW on the roof with a string inverter. PV systems of that scale are currently going for $9-11,000 top quality and $5-7,000 for good quality price-performance systems. Each has its benefits, not for this topic, but if you put in a ‘too small’ system than you need or one affected by lots of shading or ‘bird deposits’ the payback could approach ‘never’. Further, relying on feed-in credits for offsetting the equation, between enough to maxing it out, will be subject to future feed-in tariffs.
Two messages, consider the gouge vs system size and paying the retailers vs payback time; and do retailer comparisons for solar rates and plans (eg Victoria’s government sponsored energy compare) or sign up to Choice Transformer. to do it for you.