Outright purchase quote

[nomorecoal]

Hello All,
I have received a quote from a local installer and was wondering if this is a fair price for the system.

House Location: Maryland, USA
System: 6.24 kW DC (5.99 kW AC)
PV Panels: 24 x SolarWorld, Model: SW260 Mono Black
Inverters: 24 x Enphase Energy, Model: M215-60-240-S2x

Contract Amount: $23,450 ($3.76 per watt DC)
Less:

Clean Energy Grant Program - Residential Solar PV
Federal Tax Credit

Net Installed Price per Watt: $2.47 per watt DC ($2.57 per watt AC)

Thanks,
Rahul

[sganji]

Hello All,
I have received a quote from a local installer and was wondering if this is a fair price for the system.

House Location: Maryland, USA
System: 6.24 kW DC (5.99 kW AC)
PV Panels: 24 x SolarWorld, Model: SW260 Mono Black
Inverters: 24 x Enphase Energy, Model: M215-60-240-S2x

Contract Amount: $23,450 ($3.76 per watt DC)
Less:

Clean Energy Grant Program - Residential Solar PV
Federal Tax Credit

Net Installed Price per Watt: $2.47 per watt DC ($2.57 per watt AC)

Thanks,
Rahul

I think it seems to be little high. Mine was completed 2 months ago at less price. You can private message so that I can provide you with details

[prhamilton]

Seems fair to me. To me $3.60/w is a good target price in Northern California. You are in the ballpark. If you've gotten a couple other quotes and this is guy you like and you've pushed him a little bit on pricing then I think you have a fine deal. You can push him a little on price if you want to knockoff maybe a grand or maybe Maryland prices are just a bit higher.

If the installer first offer was this price then you have a pretty stand-up guy who isn't playing any games. In my book that is worth something.

[Bikerscum]

System: 6.24 kW DC (5.99 kW AC)

6.24kw DC is 5.99kw AC?

[inetdog]

6.24kw DC is 5.99kw AC?

It is with a 95% efficient inverter (a not uncommon number.)

[russ]

6.24kw DC is 5.99kw AC?

Try more like 6.24*.82 = 5.17 kW AC or possible a slight bit higher.

[Bikerscum]

Try more like 6.24*.82 = 5.17 kW AC or possible a slight bit higher.

That's what I was thinking.... salesman hype.

[nomorecoal]

82% efficiency

What is the basis of arriving at 82% efficiency?
Most inverters and optimizers that I saw state 95+ percent efficiency.

Am I missing something?

[russ]

What is the basis of arriving at 82% efficiency?
Most inverters and optimizers that I saw state 95+ percent efficiency.

Am I missing something?

Yep - the total inefficiencies come to that range - you are talking about the inverter only. The panels do not operate at STC conditions either (or rather rarely) - the point at which panels are rated is a lab situation only.

[prhamilton]

It's like everything the inverter manufactures quotes the efficiency in a lab setting where they control for every other loss of efficiency. The 82-84% efficiency thrown out here including things like inverter efficiency, wiring loss, clouds, bird poop, kids flying kites nearby, satellites etc. This 82-84% is known as the derate factor, I call it the fudge factor. You could reverse out the derate factor they are giving by taking the production estimate of the number of kwh and solving for the derate. It is a good exercise because it does reveal if they are trying to oversell or undersell power.

I think we have gotten off track what is AC kW? I am use to it representing the inverter output. It is normal for the inverter size to be smaller than the panel total wattage because it might be very rare for the panels to operate at full wattage, when they do the inverter 'clips' or drops the extra power that the panel could have made. In your case I would think your AC wattage is 215w*24inverters=5.16kW AC, that should be the peak AC wattage your system can make. I don't know where the 5.99kW came from, your 215w inverters can't make that much power.

With string inverters it is beneficial to under-size the inverter because the inverters are more efficient running at max power, so you trade off a little clipping for a spending more time at the top of the power curve. I don't know if micro inverters have the same characteristics but I would expect they do.

[J.P.M.]

What is the basis of arriving at 82% efficiency?
Most inverters and optimizers that I saw state 95+ percent efficiency.

Am I missing something?

Not to intentionally muddy the waters more, but it may be useful to mention that for every Watt of solar irradiance that crosses the plane of the array just before it hits the panels, approximately 15% to 18% or so of that energy comes out of the inverter. That's the "instantaneous" output" - strictly speaking not quite instantaneous, but usually measured over a short time period of the order of a minute or less.
That 82% is 82% of what's left after the panel efficiency is adjusted for temp., and also includes adjustments (reductions ) for all associated wiring and other equipment losses which are usually, and constantly, changing.

VERY approx. : If a panel has an S.T.C. rating of 18% --->>> ~= (.18) X ( .82) = 14.8% overall "instantaneous" system efficiency.

One common and reasonably accurate way to measure the instantaneous system efficiency (EFF.) is to record the inverter output (OUTPUT). Then, measure the horizontal solar irradiance with a pyranometer and convert that into something called "P.O.A" or plane of array irradiance. The instantaneous efficiency is the inverter output divided by product of the P.O.A times the array area (AREA), i.e., the total instantaneous input to the array.

--- >>>: EFF = OUTPUT/((P.O.A. irradiance) X (AREA))

The estimated daylong (or longer) average efficiency is simply the (sum of the inverter instantaneous outputs) divided by the (sum of the total array instantaneous inputs). The more measurements, the more accurate the estimate.

[Naptown]

Hello All,
I have received a quote from a local installer and was wondering if this is a fair price for the system.

House Location: Maryland, USA
System: 6.24 kW DC (5.99 kW AC)
PV Panels: 24 x SolarWorld, Model: SW260 Mono Black
Inverters: 24 x Enphase Energy, Model: M215-60-240-S2x

Contract Amount: $23,450 ($3.76 per watt DC)
Less:

Clean Energy Grant Program - Residential Solar PV
Federal Tax Credit

Net Installed Price per Watt: $2.47 per watt DC ($2.57 per watt AC)

Thanks,
Rahul

price is too high for here

[nomorecoal]

Here are the other two quotest hat I have so far

System: 7.67 kW DC
PV Panels: 26 x Silveo Triex-U295-black
Inverters: Solar Edge SE 7600A-US (240v)
Contract Amount: $26,850.00 ($3.50 per watt DC)


System: 7.19 kW DC
PV Panels: 22 x SunPower SPR-E20-327
Inverters: 2 x SunPower SPRm-TL w/ SPS

Contract Amount: $ $29,150.00 ($4.05 per watt DC)

Can anyone offer me guidance on the rates? I have read about someone being offered $3.75 for SunPower. With an annual demand of 12 kWh, I might be able to fullfil all my need with 26 SunPower panels (if someone can offer at lower rate).

Based on various installers, given my roof dimensions and restrictions posed by domers, I can only fit up to 26 efficient panels and 22-24 less efficient panels.