Mothernaturesolar wrote:While solar is a good idea for you, Elroy, this package from Costco is not. I'll break it down for you-
$12,203.99 cost (including tax) = $3.25 per watt. Plus you're gonna need...
$ 600 Creofix spanish tile roof stands
$ 255 Enphase trunk cables
$ 450 Enphase Envoy computer
$ 139 trunk cable stainless steel clips
$ 350 wire, junction boxes, conduit, breakers, etc
$ 300 average cost of permit
$ 168 tax on all this
$2,262 total for extras
$12,203.99 original cost
+$2,262.00 extra parts needed
$14,465.99 = $3.86 per watt for only materials
The lowest installed price in California for your size system is currently $3.69 per watt, all materials and labor included. But, that company is based in the Northern California bay area, and you live in Southern California. For 2012, in the entire state, the average installed price for a 3.75 kw system is close to $6.00 per watt (per the California Solar Initiative website). Two weeks ago in Castro Valley, I saw a bid by Solar City for a 3 kw system, and they wanted $6.67 per watt. Yikes! It's very surprising to me that the prices are still so high, because the material costs for a solar system have plummeted this year. It's sort of like when the price of a barrel of oil drops a lot, and the price of gasoline doesn't.
So you should look for a bid from a solar company for between $3.69 per watt and $6.00 per watt. For that, you should expect- 1) a complete system installed, all labor and materials 2) the installer to do all the paperwork and drawings for the building permit application, all paperwork regarding your utility rebate, and all paperwork regarding your new solar meter 3) an internationally known brand of solar panel (not Grape), made by a strong, non-Chinese based company that'll hopefully be around for the full 25 years of the panel guarantee.
If you can find a licensed contractor, with solar experience, who will do it for $4.50-5.00 a watt or so, go for it.
Good luck Elroy!
Mothernaturesolar wrote:And is having only a 10yrs material and workmanship warranty the norm? For the system as a whole? Yes.
Is 18% efficiency high end or just average? High end.
The average efficiency is between 14% to 16% for solar panels. But keep in mind, efficiency is primarily a smoke screen by solar companies so that they can charge higher prices. But a high efficiency 250 watt panel doesn't put out more power than a standard 250 watt panel, it just puts out the same amount of power with a smaller panel. It's quite unimportant if your panels cover 100 square feet less of your roof with high efficiency panels than with standard panels. Do you think anyone would ever notice or care? What you really need to know is- How much are you going to pay for each watt produced?
A 4 kw system with standard 250 watt panels is no different than a 4 kw system with high efficiency 250 watt panels. The standard system has 16 panels, the high efficiency system has 16 panels. The high efficiency panels will take about 25% less roof area, therefore they put out more power per square foot; but, they still only produce 4 kws, just like the standard panels. The important differences are- 1) a standard 4 kw system is much cheaper 2) a standard 4 kw system coupled with Enphase M215 inverters will actually outproduce a 4 kw system of high efficiency panels coupled with a DC inverter 3) you pay much more per watt produced for high efficiency panels than with standard panels.
With standard panels, you'll pay anywhere from $3.69 to $6.00 per watt installed, and with the high efficiency panels you'll be lucky to be below $6.00 a watt, and often the price will be higher.
The only time to consider high efficiency panels is when you have a small amount of roof area available for your solar system (remember, a high efficiency 250 watt panel is smaller than a standard 250 watt panel). Therefore, you can fit more panels into a limited roof area.
If you have enough roof area, as most people do, the high efficiency panels NEVER pay off better than the standard panels.
Mothernaturesolar wrote:These Costco panels appear to be about 3.25ft x 5.3 ft.
Are those high efficiency panel dimensions? No, that's the standard size
If so, how do stock efficiency panel dimensions compare? 2.5ft x 5ft
Also, with my 985kWh consumption for the month, what size system is needed? With south-facing panels, a 6.75kw system will cover all your consumption. But you would actually need a smaller system, from 5.5kw to 6kw, to reduce your bill to zero since you'll receive the solar benefits of time-of-use billing.
It appears that even with a 6kw system, you will fall short especially at this time of year. You stock up your excess solar credits during the summer with time-of-use billing, and use them during the winter.
Mothernaturesolar wrote:So this is around a 7kW system with 31 panels I believe.
And yet I am consuming on average 26-30kWh per day....and this huge system would have only covered 1/3 of my energy needs today?
Elroy, the numbers are down because it's been cloudy and raining in Roseville all month. Solar panels don't run on clouds or rain. Even without clouds or rain, panels have less production in the winter cause the sun is low, and more in the summer cause the sun is high.
If Con Edison has cheap baseline charges like PGE, and if they're 4,800 kwh per year like PGE, a good size system for you would be 4.25kws. It would produce 7,437 kwh's per year (facing due south), and therefore would reduce your electric bill comfortably into the cheap baseline electric charges.