Solar system in Las Vegas

[lanb]

Thanks for the info sensij.

I will play around with pvWatts to get the kWh estimate.

BTW, both quotes are from the same installer/company.

[sensij]

Looking to go solar for a 11500 kWh/year capacity system.

Here are the initial quotes I have gotten

6.72 DC kW with 21 Solarworld 320 panels with Solaredge inverter producing 11503 kWh/year - $21,821 ($3.24/kWh)
Warranty is 10/10

5.886 DC kW with 18 SunPower 327 panels with SMA inverter producing 11118 kWh/year - $25,528 ($4.33/kWh)
Warranty is 25/25

Now the questions -

1) Does that look like fair pricing ?

Hard to say without more details, but for a straightforward install, yes, that looks like competitive pricing. The discrepancy between kWh estimates is worth understanding better. Two arrays with similar kW ratings will have similar kWh output. Either Sunpower is overestimating or the Solarworld installer is underestimating. Spend some time with PVWatts and see if you can come up with your own estimate. Try dropping the loss factor from the default 14% to 10%, or perhaps less.

2) The installer mentioned that Solarworld 320's are way back ordered and wants to substitute with 280's (more panels).
He said that 280's are built with better cells. True or False ?

Well, the SW320's are 72 cell panels, so if you scale that to 60 cells, it is something like a 265 W panel. The 280's are 60 cell panels, so in that respect, they should have higher cell efficiency (meets the definition of "better"?). I don't really see anything wrong with subbing the 280's, if the roof layout works for either 72 cell or 60 cell panels.

3) I have been reading about the risk of solarworld proprietary optimizers and what happens if they go out of business.
Is it possible to install solarworld panels without optimizers and just a string inverter ?

Yes, Solarworld panels can be installed with a string inverter.

[lanb]

Bump

Bumping up the post for answers

[lanb]

Looking to go solar for a 11500 kWh/year capacity system.

Here are the initial quotes I have gotten

6.72 DC kW with 21 Solarworld 320 panels with Solaredge inverter producing 11503 kWh/year - $21,821 ($3.24/kWh)
Warranty is 10/10

5.886 DC kW with 18 SunPower 327 panels with SMA inverter producing 11118 kWh/year - $25,528 ($4.33/kWh)
Warranty is 25/25

Now the questions -

1) Does that look like fair pricing ?
2) The installer mentioned that Solarworld 320's are way back ordered and wants to substitute with 280's (more panels).
He said that 280's are built with better cells. True or False ?
3) I have been reading about the risk of solarworld proprietary optimizers and what happens if they go out of business.
Is it possible to install solarworld panels without optimizers and just a string inverter ?

Thanks for all the helpful info here !