New to solar, have bid from Solar City

[KRenn]

Forgive me, I only meant they were similar looking, esthetic wise. But thank you for the hard numbers on the efficiency differences.

I've already got one of the SunPower guys onboard with using Power One 6000 inverter. He agrees.

Also, I asked what the electric panel replacement cost me, he said it was priced at $2000 for purchase, but for my prepay lease he only added $1100 to the bid. I really don't understand what that means but there you have it.[

That's pretty straightforward. Your overall price on a system might be $50,000 if it was a direct purchase but the prepaid price might be $25,000, if you tack $2000 on to the purchase price it would add about $1000 to the prepaid price you'd be paying.

[Rockit31]

Not at all. Sunpower efficiency is 20%, Canadian efficiency is about 15%, that means a great deal more roof space required for the Canadian panels. Depending on your climate, the Canadian's have a temp coefficient of -0.45 as compared to Sunpower's more advantageous -0.38 which means better overall production in hot weather.

Forgive me, I only meant they were similar looking, esthetic wise. But thank you for the hard numbers on the efficiency differences.

I've already got one of the SunPower guys onboard with using Power One 6000 inverter. He agrees.

Also, I asked what the electric panel replacement cost me, he said it was priced at $2000 for purchase, but for my prepay lease he only added $1100 to the bid. I really don't understand what that means but there you have it.

[KRenn]

Well that's the thing. The Sunpower guy determined the best areas (basically running a single line along the top of my ridge, with 2 to 6 more panels along a row underneath. There is still going to be some shading of course, but with a 42 panel system, they're going to have to put them in more places where shade will be a bigger factor.

Here is a link to Canadian's CS6 panel. http://www.canadiansolar.com/en/prod...s6-series.html

Here are Sunpower's E20's http://us.sunpowercorp.com/homes/pro...ar-panels/e20/


Pretty similar except for the grid lines.

Not at all. Sunpower efficiency is 20%, Canadian efficiency is about 15%, that means a great deal more roof space required for the Canadian panels. Depending on your climate, the Canadian's have a temp coefficient of -0.45 as compared to Sunpower's more advantageous -0.38 which means better overall production in hot weather.

[KRenn]

With the fewer panel arrangement, can they be located so as to avoid the shading issue? Sunpower pushes their own rebadged SMA inverter for the lease so not sure if you can substitute a competitor. Only you can ultimately decide on the esthetics. That was certainly of significant value to me as I could have had probably 20-30% more panels but the additional ones would have been fully visible while the existing ones are pretty much hidden. In your case, the all-black modules are probably not bad looking. How would they compare looks wise with the SP panels?

You have the choice of using Fronius, SMA or Power-One inverters for any Sunpower system. They're all re-branded under the Sunpower logo and Power-One seems to be the preferred inverter since it is transformerless, performs better than any other inverter in high heat and uses dual-MPPT based technology, it'll actually result in higher overall output.

[Ian S]

Well that's the thing. The Sunpower guy determined the best areas (basically running a single line along the top of my ridge, with 2 to 6 more panels along a row underneath. There is still going to be some shading of course, but with a 42 panel system, they're going to have to put them in more places where shade will be a bigger factor.

Here is a link to Canadian's CS6 panel. http://www.canadiansolar.com/en/prod...s6-series.html

Here are Sunpower's E20's http://us.sunpowercorp.com/homes/pro...ar-panels/e20/


Pretty similar except for the grid lines.

I guess the only other things to consider involve the lease agreements and their details. Option for buyout during the lease? Options at lease end? I know with Sunpower, they're the lessors so it probably doesn't matter if your installer disappears at some point. What about the other lease? I would also ask for customer contacts who have had installs completed this year. That will give you an idea of how well the installer/supplier is coping with the current flux in the industry. Were there delays or other hassles for example?

[Rockit31]

With the fewer panel arrangement, can they be located so as to avoid the shading issue? Sunpower pushes their own rebadged SMA inverter for the lease so not sure if you can substitute a competitor. Only you can ultimately decide on the esthetics. That was certainly of significant value to me as I could have had probably 20-30% more panels but the additional ones would have been fully visible while the existing ones are pretty much hidden. In your case, the all-black modules are probably not bad looking. How would they compare looks wise with the SP panels?

Well that's the thing. The Sunpower guy determined the best areas (basically running a single line along the top of my ridge, with 2 to 6 more panels along a row underneath. There is still going to be some shading of course, but with a 42 panel system, they're going to have to put them in more places where shade will be a bigger factor.

Here is a link to Canadian's CS6 panel. http://www.canadiansolar.com/en/prod...s6-series.html

Here are Sunpower's E20's http://us.sunpowercorp.com/homes/pro...ar-panels/e20/


Pretty similar except for the grid lines.

[Ian S]

Believe me, that is a big consideration in my choosing the right system. I have the room and all for 42 plus panels , but 24 would sure look nicer IMO.

What's everybody's thoughts on this? Say you had the room, and all prices were pretty equal, knowing my shade issues, would you opt for a microinverter 42 panel 9.8kwh system guaranteeing 12,929kwh using the CanadianSolar all black CS6P modules and Enphase microinverters OR would you go for a Sunpower 28 panel 9.16kwh system guaranteeing 12,671kwh?

With the fewer panel arrangement, can they be located so as to avoid the shading issue? Sunpower pushes their own rebadged SMA inverter for the lease so not sure if you can substitute a competitor. Only you can ultimately decide on the esthetics. That was certainly of significant value to me as I could have had probably 20-30% more panels but the additional ones would have been fully visible while the existing ones are pretty much hidden. In your case, the all-black modules are probably not bad looking. How would they compare looks wise with the SP panels?

[Rockit31]

Something else to consider is that it may be easier to locate 24 or 28 panels in such a way as to avoid shading compared to doing it with 42 panels that presumably cover significantly more area. That would I suppose depend on efficiency.

Believe me, that is a big consideration in my choosing the right system. I have the room and all for 42 plus panels , but 24 would sure look nicer IMO.

What's everybody's thoughts on this? Say you had the room, and all prices were pretty equal, knowing my shade issues, would you opt for a microinverter 42 panel 9.8kwh system guaranteeing 12,929kwh using the CanadianSolar all black CS6P modules and Enphase microinverters OR would you go for a Sunpower 28 panel 9.16kwh system guaranteeing 12,671kwh?

[Rockit31]

All prepaid leases are going to have guaranteed production amounts, while usually conservative, at least its a sound number to rely on. If the shading is that limited, you can get away with a central inverter, although with Sun power I would absolutely, 100% insist on them using Power-One inverters which possess dual-MPPT technology and limits shade-related loss by a significant amount.


However if the pricing and production are equal, with the shade considered, I would choose the Real Goods solution, I'm not a huge fan of micro-inverters by any means but in your case it seems like they could do you a lot of good. Now if the 2nd SunPower guy comes back on Monday with a quote that is say $3000 less and utilizes Power-One inverters and includes the panel upgrade, I'd have no problem recommending that solution.

I forgot to bring this up. When I talked to one of the SunPower guys, and explained my issue with shade and my new found knowledge of how 1 panel on an array can turn the whole string to ****, he fired back about SP's technology and how it mitigates things like that? I don't remember exactly what it was about their "patented" technology, but he did not describe anything about a special inverter doing the magic, I seem to remember it was in the panels themselves.

I believe they wanted to use SMA inverters? So I should insist on Power-Ones? How do Power-Ones help mitigate efficiency loss on a string due to shade?

[Ian S]

I believe that Leases will dominate the market in 2013, but prepaid and "regular" leases will become less popular as new loan programs like PowerSaver become available.

I dunno. Seems to me leasing should always have a leg up due to accelerated depreciation that's not available to an individual who borrows to buy their system.

[JGSolar]

Look into loan programs.

Was it this thread where the future of the lease was headed after 2016?

I believe that Leases will dominate the market in 2013, but prepaid and "regular" leases will become less popular as new loan programs like PowerSaver become available.

[SoCalsolar]

I vote for the micros or

I vote for the micros or purchase of a non-SP panel if you plan to be in the home for 10+ years. What size main panel do you have? That upgrade is one you only want to do if you have to as it only adds cost to the project no wattage. if you do choose SP you should get a better price with SP if you pay for the main panel upgrade separately from the lease. Ask them to run the numbers with the main and without the main and find out what they charge for the main panel upgrade. Negotiate the lease price separately from the main then leverage your decision on which dealer on the price of the main panel upgrade. What happened to the SC guy? Was it this thread where the future of the lease was headed after 2016?

[Ian S]

Re: Shading

Something else to consider is that it may be easier to locate 24 or 28 panels in such a way as to avoid shading compared to doing it with 42 panels that presumably cover significantly more area. That would I suppose depend on efficiency.

[HappyInMa]

Shading....

Shading does make quite the difference... I have some both in the morning and afternoon on my array (central inverters). If I can get the graph to insert below you can see the effect in the production curve on an (essentially) cloudless day. If you look at the curve (sorry that it is upside down - TED shows production as a negative number) but the production is the light blue. You can see how the production starts in the morning (curve begins) then shade hits and it falls until about 10:45 when the last bit leaves the array and then production jumps. Then again around 3:15p it falls as the afternoon shade begins to hit until it passes at about 5p and the production jumps again (obviously a lower spike as it is later in the day). You can visualize where the curve "should" be and imagine all that lost productivity...

Prod_Graph.jpg

In the winter it is harder to see on the graph, but I have some shading that kills the bottom row of my array from trees across the street. Bottom line - it really bites into production. I knew this going into the decision so I wasn't surprised as such, but actually seeing it was still a bit of a surprise.

Anyway my point is, don't under estimate the damage shading can do to your production. With trees it likely will only get worse over the next 5-15 years as they tend to grow.

On a different topic - one argument for the microinverters has been that they have a longer life - this is great for those of us buying the systems outright, but for a lease I expect this benefits the person paying for the warranty more as the replacement of the central inverters (and production downtime) may fall on them. Had I found installers with more knowledge/comfort with microinverters when I put my array up I very likely would have opted for them. I will be looking that route when I expand my array in the next couple years.

[Ian S]

So I've had 2 other Sunpower guys come out. They both think I do not need a microinverter system. The first one even had the shade tool, got on the roof and came back with an overall shade factor of 84%. He calculated that into my 24 panel sized system (7.8kw), added the cost of replacing my electrical panel, and has me priced at $25,618 for prepay 20 year lease.

The second guy came out with opening bid of $22,500 for same system but had not calculated shade nor panel replacement yet. He came by yesterday to take shade measurements and we will meet on Monday for his final bid.

The first guy's estimate with 24 panels using the 7000m inverter guarantees 10,861kwh of production. Based on the fact that I used over 15,000kwh last year, this would leave me with an estimated electrical bill of $57 per month.

He then threw in a bid using 28 panels with the 8000m inverter (9.16kw), which would cost me $28,952 for lease and guarantee 12,671kwh per year. Residual electrical bill of $29.


So at least I'm getting some hard quotes now, figuring in my shade.

Oh, the guy from Real Goods Solar, who wants to go with a microinverter setup using the Enphase inverters, quotes me at $28,065 for prepay lease. This is a 9.55kw sized system, I think upwards of 42 panels. He also went on the roof with his shade tool and has calculated that and the panel replacement in his bid.


What do you all think? Am I better served by microinverters, or is it not necessary considering my shade factor? Looking at one of their graphs, my house would kick butt from March to October (95 to 100% shade factor), it's the other months where some tall trees would put a hurt on me.

Well, the RGS system is over 20% larger in power for less than 10% more in cost than the 7.8 kWh system. And that includes the costlier microinverters. Have you looked over the actual contracts to see how other factors compare? Who is responsible for insuring the system? Are there up-front payments prior to installation? What happens if you sell the house - can you do a buyout if necessary? What happens at lease end? Monitoring included? Roof penetration warranty?