So full disclosure, I work in a position that allows me to invest in new products and solar is something I have been looking at bringing into our business since 2012 however I do not want this to come across as an advertisement I am after opinions on the viability of solar at a price point.
A touch over a year back I asked the question on geekzone “What price does PV solar have to be to make sense?” I got alot of responses (Thank you) I looked issues that were raised and I would be interested in hearing feedback to my solutions.
First of all one of the biggest problems with solar is cost and scalability of that cost for example, a 4kw system average installed cost per watt is $3 per watt but a 1.5kw system is $4 per watt however due to the solar production curve, the cost (and lifespan) of batteries and the working habits of a average New Zealander the larger system is not going to give a good return on investment as, during the day a large amount of power will be pumped back into the grid at 8c per KW.
So lets look at the average costed small system at $6000 for a 1.5kw system I will be taking into account my own weather data and assume we are on a good roof pitch facing north.With those conditions the 1.5kw system would be producing 2056kw annually, on my low user plan I am paying around 29c per KWH. Now assuming you can use all the power produced on the low user plan you are looking at around $600 per year. So without taking into account electricity price rises or efficiency decreases of the panels you are looking at an absolute best case scenario of a 10 year payback or 10% return PA on investment. From you and others have said this is not good enough to justify the outright purchase. So to make solar appeal to the mass market and make better financial sense that would mean dropping the price per watt of the smaller systems to take care of the base load below the price per watt of an average larger system.
So if we took a 1.5kw system and priced it at $3999 installed (installed cost per watt $2.66) using the same calculation as above you would be looking at a payback of 6 years 7 months or 15% return PA on investment if you took into account a 17 month no interest no payment plan you would be looking at $2.10 per watt and a payback of 5 years 2 months or a 19% return PA on investment. All this is assuming a best case scenario (in terms of utilizing power the system produces) and low user power plan (less cost per day higher cost per kwh) location power production could be higher or lower than my own house.
What I would like to know is in your situation what would you estimate the payback of a small system like this to be working off the cost of power in your location and your usage habits? Would you change your usage habits if you got solar?
Personally I have this 1.5kw system installed on my own house so if you have any questions feel free to fire away.