Solar Panel Discussion

I built an annual 12-month NEM model in MS Excel last year, using miimura's file as a starting point and PVWATT's data so that I could accurately determine the PV system size I would need to maximize my cost benefit and minimize the amount of time to payoff. It also allowed me to determine that based on my real-world PG&E prior usage, the BEST rate plan for my conditions would be the EV-A plan. I built the ability to load in 12 months worth of PG&E data, and have a bucket for additional "regular" usage or additional "EV" charging, since I hadn't had my Fit EV for more than a couple months then. I brought in the PVWATT's data, and added the ability to scale it up or down, as well as the ability to turn it off completely. What amazed me was the fact that whether I had solar or not, that EV-A was the best rate plan based on my usage. It all varies on each individual's usage patterns and your location -- PGE has different baselines for Tier plans based on your region: http://www.pge.com/baseline/

I ended up with a 4.69 kw system. Consisting of 14 x 335 watt SunPower Black panels, 1 SMA Sunnyboy 5000TL inverter (includes a 120V plug to bypass the grid if there are ever outages). I had no shading issues, so a single inverter seemed the best way to go. I don't regret that decision at all. My installer was an old friend of mine, who normally does larger scale commercial projects and was able to get me some great discounts on the SunPower panels, which look extremely awesome in all black. Makes it look like I have a roof covered in the monolith's from 2001: Space Odyssey. My total cost before 30% Fed tax credit was $18,000, so after I claimed my 30% tax credit, my final total cost was $12,600 (that ends up at $2.69/watt, which is far better than any quote I got from installers like Pederson Dean, SolarCity, Verengo, and SolarWorld). It will have paid for itself by year 6 according to my model and assuming average PGE rate inflation of 3% per year.

I installed in November, and so far production has been 20% more efficient than the PVWATTs model predicted for my specs. My guess is half of that 20% is due to better weather (less clouds and fog than average) than predicted by the PVWATTs model. In any case, I'm thrilled at the performance and monitoring capabilities. Here's a link to my system: https://www.sunnyportal.com/Templates/PublicPageOverview.aspx?plant=62cd8906-e96a-4add-a531-972328819227

If you live in the Bay Area, send me a PM me if you'd like my installer's contact information. He's currently prepping jobs for 2 of my other neighbors, so I know he's still interested in doing Residential jobs at the moment until his next large scale commercial installation.

One last thing if you want a good piece of advice from someone that went through the due diligence of getting multiple quotes, dealing with salespeople and actually trying to makes sense of all their numbers: stay far far away from Verengo and SolarWorld. Terrible sales tactics, repeatedly lied to me, and felt like typical high pressure sales people that couldn't even come close to reasonable quotes, and had no understanding of how NEM works or the ability to explain it. SolarCity also was a TERRIBLE experience and they wanted almost twice the money for the same size system if I bought from them. Leasing from companies like SolarCity only makes sense if you want to be "green" and would rather pay electricity rates to a solar company instead of paying them to PG&E. When I put their lease numbers into my model, there really wasn't a cost benefit to a homeowner at all, you end up locked into a contract where you're just paying SolarCity the same amount over time that you'd be paying PG&E. If you ever want to piss off a SolarCity sales guy, just ask what happens when you want to sell your home before your Solar lease runs out. It just makes way more sense to buy your system outright and actually own the rights to it and the NEM agreement with PG&E. Finance it if you have to, don't just throw your money away on a solar lease.

Just for the sake of price comparisons (to own not lease a PV system), the total I paid for my 4.25kW system based on 17, M215 Enphase microinverters, as provided and installed (including the cost of the permit) by PD (Petersen Dean), was about $15.5k. That was the total price I paid before the 30% federal tax credit, however I did have to forfeit the CA rebate, which would of been worth about $700. Thus, the net cost was just under 11k, or ~$2.60/watt. The PD sales guy I worked with was terrific, who included in the initial quote a $1000 discount due to special promotions going on at the time. Since the initial install, PD replaced one of the M215 at N/C to me, fully covered under warranty. Unfortunately, I don't think they do Enphase systems anymore, so I'm glad I got mine when I did. :mrgreen:

red_stripe05 said:

Leasing from companies like SolarCity only makes sense if you want to be "green" and would rather pay electricity rates to a solar company instead of paying them to PG&E. When I put their lease numbers into my model, there really wasn't a cost benefit to a homeowner at all, you end up locked into a contract where you're just paying SolarCity the same amount over time that you'd be paying PG&E. If you ever want to piss off a SolarCity sales guy, just ask what happens when you want to sell your home before your Solar lease runs out. It just makes way more sense to buy your system outright and actually own the rights to it and the NEM agreement with PG&E. Finance it if you have to, don't just throw your money away on a solar lease.

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I had this line of thinking originally, too, but after numerous quotes from installers both for purchase and lease, SolarCity's 20 year lease paid up front was the most cost effective. Maybe it's because I'm in LADWP territory, but the simple fact is that my SolarCity leased system was the best deal, and I have no issues transferring the system when I sell my house. I paid less than $1/watt installed and serviced for 20 years.

I would strongly encourage anyone considering solar to get quotes from all vendors for both purchases and leases. For me, SolarCity couldn't be beat and they've provided good service thus far.

Wow $4,000 up front and $16,000 residual does seem like a great deal.
I assume SC would otherwise remove the equipment for free.
Can't see how SC can make money on this.

When I talked to Solar City approximately 3 months after the above contract was executed (September 2012) they would not offer me a straight lease, prepaid or otherwise, only straight purchase (way overpriced) or a Power Purchase Agreement. The situation today is clearly different than when this contract was executed. I'm not saying it's necessarily better or worse, but different.

miimura said:

When I talked to Solar City approximately 3 months after the above contract was executed (September 2012) they would not offer me a straight lease, prepaid or otherwise, only straight purchase (way overpriced) or a Power Purchase Agreement. The situation today is clearly different than when this contract was executed. I'm not saying it's necessarily better or worse, but different.

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Maybe there's a PG&E factor there? They're known to be fairly hostile to solar. SolarCity still offers leases, PPAs, and purchases according to their website.

DevinL said:

miimura said:

When I talked to Solar City approximately 3 months after the above contract was executed (September 2012) they would not offer me a straight lease, prepaid or otherwise, only straight purchase (way overpriced) or a Power Purchase Agreement. The situation today is clearly different than when this contract was executed. I'm not saying it's necessarily better or worse, but different.

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Maybe there's a PG&E factor there? They're known to be fairly hostile to solar. SolarCity still offers leases, PPAs, and purchases according to their website.

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I don't know why they would have (temporarily?) discontinued their lease program, but I got quotes for prepaid leases from SolarCity back in September 2011 in a PG&E domain: Santa Cruz. (I ended up going with slightly better panels and a slightly lower-priced prepaid lease from SunPower instead.)

As an aside, the terms on my lease deal with SunPower are a little special and no longer available. It includes an interesting, optional lease buy-out option at around year seven for 5% of the total lease cost. In other words, rather than having to choose between buying the system after 20 years or risking the possibility that the company will take the system back, you can choose to buy it cheap earlier on, when they've exhausted the business credits on their end of the deal. It still works out to be *MUCH* less than an outright purchase contract. I haven't decided yet whether I'll choose to take them up on that.

When the SolarCity rep caught wind of this deal though, he got quite bent about the legality of it, bad-mouthing SunPower as well as complaining loudly to his own people about why they weren't offering such a deal. Six months later I heard that SunPower was no longer offering the buy-out option on their leases. ;-)

I also had a bid that used SunPower lease financing with that early buy-out and it was attractive. However, with the split orientation of my roof and the winter shading issues, I decided I should go with Enphase inverters and that installer did not "believe in" using Enphase. Basically, they expected field failures and didn't want to be on the hook for the labor to change them out. This was nearly two years ago, so I don't know if they still feel that way.

I'm new to this community, having just leased my Rav4 yesterday, but I thought I'd chime in on the solar discussion.

I've had a very small 2.4kW system installed for 1.5 years on my house. It consists of 10 Sunpower panels with individual microinverters, since my roof is a bit complicated. SolarCity wouldn't even consider me as a customer once they took a look at my roof on Google Earth. I'm very energy conscious and live by myself, so 2.4kW was almost 3 times more than I used until I got the EV.

I decided to purchase the system instead of lease, since I don't think I'll be keeping this house for more than 10 years and didn't feel like the hassle of transferring the lease to a new owner or uninstalling and taking it with me to a new house. Leasing something that isn't mobile wasn't something I thought was a good idea, though I understand the need to not have large upfront costs for most people.

Looking back, I'm not sure it was worth it for me for a couple reasons. One is that this system is both too big for my needs but the smallest anyone would install. I paid roughly the same installation fee as people with twice as large systems, so it was a much larger percentage of my total install cost. Also, LADWP charges a minimum monthly bill, so even though I'm generating and banking kW/hrs I still have to pay money to LADWP each month. This would be OK if I were generating a LOT more than I used, but my system isn't big enough for that. It should get better with charging my car, though. My hope is that when it comes time to sell the house, the added value of solar installed already will increase the sales price by a few thousand and make up for it that way.

boarder said:

I decided to purchase the system instead of lease, since I don't think I'll be keeping this house for more than 10 years and didn't feel like the hassle of transferring the lease to a new owner or uninstalling and taking it with me to a new house. Leasing something that isn't mobile wasn't something I thought was a good idea, though I understand the need to not have large upfront costs for most people.

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That's one of the draws of a prepaid lease: you get a big discount over a full purchase and there's no lease payments to convince a new owner to take over. Of course, a normal solar PV system lease is only for 20 years so you have to decide what to do at the end: buy out the remaining value or risk having them come and take it back.

boarder said:

Looking back, I'm not sure it was worth it for me for a couple reasons. [...] It should get better with charging my car, though. My hope is that when it comes time to sell the house, the added value of solar installed already will increase the sales price by a few thousand and make up for it that way.

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Yeah, I think you'll find it easy to use up that excess with the RAV4 EV. It's not the most efficient EV and it's easy to use up plenty of kWh's with any EV – particularly when you know you're driving on "free" solar energy! Enjoy!

The way they still make money on the prepaid leases is through taking the depreciation on the system as if it's a business item they own, which they do. Plus, they now have a big wad of cash they don't have to chase for 20 yrs. as the system changes hands a couple of times.

If you look at my buyout option, it's at exactly the time they can no longer take depreciation on the system. So if I buy out this year, the price is ridiculous, but it goes down until year 7, then it goes up again, incentivizing me to purchase it and save them from buying me 2 new inverters before the lease is up. Already had one inverter go, so the lease was an excellent value for a lot of reasons.

boarder said:

I've had a very small 2.4kW system installed for 1.5 years on my house. It consists of 10 Sunpower panels with individual microinverters, since my roof is a bit complicated. SolarCity wouldn't even consider me as a customer once they took a look at my roof on Google Earth. I'm very energy conscious and live by myself, so 2.4kW was almost 3 times more than I used until I got the EV.

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I am in a similar energy use/needs situation to yours, except that I got the car first and will get the solar system second. With the added draw for charging an EV, my electric bill would have gone from under $400/yr to almost $2100/yr (though switching to PG&E's EV rate schedule should dampen that down to $1100/yr). Much less that what I used to pay for gasoline, but not insignificant. Adding a small 2.4kW solar system (which is all that will fit on my available sunny roof area) should drop that back down to around $400/yr and maybe even lower. It won't fully zero out my electric use, but I estimate the payback time for $ savings to be around 15 years and that seemed reasonable enough for solar components with a 25-year manufacturer's warranty. Plus, now I get the "green" satisfaction of going partially solar. The cost (around $11,000 net after figuring in the Solar Tax Credit) is high compared to what people on the forum have payed for systems twice that size, but I attributed that to fixed installation costs. Based on your comments, I think that guess was correct. My system will be comprised of eight LG 300 watt modules and eight Enphase M250 micro inverters. I only have praise so far for the local installer (A-1 Sun, in Berkeley). They came highly recommended by an electrician I trust. They have been responsive and accomodating - even provided me with a rough estimate of monthly-average kWh produced before and after 2pm (the afternoon break point on the EV rate schedule between peak and partial peak hours).

One extra thing I will add. I got help from a (nice) fellow forum member crunching the numbers to confirm that the EV rate schedule was the better bet (vs. E-6) for my situation. If you've had solar for 1.5 years, you are probably already on some time-of-use rate schedule, and may even have actual a nice chunk of historical generation data for your installation. You may want to re-evaluate available electrical rate options.

After doing a bit more research and reading the various comments we decided to get another estimate on a 4.4 KW system with the SMA string inverter as opposed to the Enphase microinverters. The total cost before incentives was $16,996. I'm not sure how this quote compares to other ones.

I figured out that since we were planning on installing a 100A sub panel in the garage the string inverter could be mounted in the garage where it would be kept in a more moderate environment, and noise (if any) would not be an issue. We also don't have any issues with shading of panels so the string inverters would likely be more cost effective, and my wife seems to like the backup power during the day feature on the SMA. I still think the microinverters would be a cleaner install, but the lower cost and other benefits make it better to use a string inverter. We are also upgrading our main panel to 200A from 100A so the cost for the panel upgrade and sub panel install will be about $2500.

Regarding the reliability of the string inverter, I am wondering if it would be cost effective to spend the money up front ($450) and get a 10 year extended warranty as it is likely the string inverter will fail at least once in the life of the system even if it is indoors.

Also has anyone opted for a monitoring system such as Egauge? See the link below. The cost is ($575). It seems to add a real time monitoring capability with a web interface.
https://www.egauge.net/

Any thoughts or ideas or welcome. Thanks in advance.

Also has anyone opted for a monitoring system such as Egauge? See the link below. The cost is ($575). It seems to add a real time monitoring capability with a web interface.

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The optional SMA WebConnect module (ie, Ethernet card) costs less than an Egauge logger, comes with free real-time web monitoring through SMA's Sunny Portal, and is elegantly housed inside the inverter itself. The install in our garage is dead silent, even during peak production. We didn't go with the additional 10 year warranty.

swogee said:

I figured out that since we were planning on installing a 100A sub panel in the garage the string inverter could be mounted in the garage where it would be kept in a more moderate environment, and noise (if any) would not be an issue. We also don't have any issues with shading of panels so the string inverters would likely be more cost effective, and my wife seems to like the backup power during the day feature on the SMA. I still think the microinverters would be a cleaner install, but the lower cost and other benefits make it better to use a string inverter. We are also upgrading our main panel to 200A from 100A so the cost for the panel upgrade and sub panel install will be about $2500.

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The location of a string inverter probably depends more on the routing of the high voltage DC wiring than the panel you connect it to. Also, I've always seen solar circuits fed into the bottom of the main panel, never any other location. However, this may depend on your local permitting jurisdiction and inspector.

Net utility usage 995 kWh, cost $32. Got to love TOU-EV-SOLAR.
3kW DC solar produced 530 kWh.
August numbers.

SDGE Rates for net metering:

So I finally got around to using Miimura's spreadsheet to evaluate various SDGE rates with my Solar net metering and EV charging. There were several surprises (actually I had my suspicions).

First, has anyone else noticed SDGE EV TOU and TOU2 rates show different summer and winter rates (https://www.sdge.com/sites/default/...Effective - Schedules EV-TOU & EV-TOU-2_0.pdf), but their calendars shows the same rate ALL year 7 days a week?(https://www.sdge.com/sites/default/files/documents/1894968859/2014-dst_ev-tou_epev.pdf ; https://www.sdge.com/sites/default/files/documents/1269645843/2014-dst_ev-tou2.pdf)
What's up with this; how can we get summer / winter rates if there are no winter months??

Second, I have not switched from my SES rate to an EV TOU rate yet because I was worried the more restrictive hours would hurt instead of help. I downloaded meter info for the month of September 2014 and loaded it into the spreadsheet. Then I modified 3 rate structures to reflect the 3 rates for comparison; my DR SES rate, the EV TOU and EV TOU2 rates. It took some time to modify the parameters and be sure the data was loading into the correct bins depending on the time of day, weekday / weekend, etc.

Next I created a summary area to calculate and total the charges for each rate. The "charges" are as follows:

DR SES EV TOU EV TOU2
$20 $54 $14

I still have an issue with the spreadsheet loading weekend off-peak charges into the super off peak column. This will cause the EV rates above to be lower than actual.

The EV TOU rate requires a second meter, so that is definitely out. The EV TOU2 rate shows promise but I need to tweak the spreadsheet to assure everything is properly sorted, then run the entire year to be sure a change is worthwhile.

As you know, once you switch rates with SDGE you are committed for an entire year. I'll post more after I have the entire year of data analyzed. I'll be tracking down Miimura for some help with the formula tweaks for the SDGE schedules. Also, if anyone has intel on the summer / winter calendar for the EV TOU rates please share.

Read this today: http://finance.yahoo.com/news/elon-musk-just-made-way-191500709.html

I was really surprised by the comments that followed the news article.

I am in the last steps of installing my own solar system. Going live after inspection next week.

Summary: I got quoted $30,000 from Solar City for a 5.5kw system, did the job myself for about $12,000.

I went with 4th gen enphase m215 and 24x230watt panels.

Enphase inverters, Enphase gateway(monitoring) and all hardware to mount all 24 panels on the roof cost $6000 from Renvu. The panels cost about $3600 (off craigslist). Copper wire, permits, labor, all other small things were around $2400. Thats 12k. Add another 1000 for things I forgot. Puts me in at 13k. Minus 30% govt rebate leaves me at 10k. This is conservative, I am actually going to be closer to 9k

Took me and a retired electrician/general contractor one day to mount the framing on the roof. One day to run the wiring through the attic etc and half day to mount the panels. Thats 5 man days. Could have been done in 4 if we didnt waste so much time hanging out.

My project is conisdered complex because:
1- Panels are going on the 2nd story
2- 3 roof planes are having panels installed (8x8x8)
3- Theres a lot of distance from the panels to the electric panel (150 feet of wiring, drilling through walls and fishing wire, etc)
4- Attic vents, bathroom vents and sewage vents all had to be relocated to make space for the panels

It took me about a month of using youtube, reading forums etc. to get confident in my knowledge to move foward with the work.

Now I have enough power for my home and for 50 miles of commuting daily. Not only am I driving on electric power... I am driving on pure Sun Power

If you are at all handy and like to educate your self and like to learn new things then you should have no problem doing it yourself. If you have lots of $$ and you want worry free "I came home after work and theres a solar system on my roof"... then go with SolarCity/etc.

Conan said:

I am in the last steps of installing my own solar system. Going live after inspection next week.

Summary: I got quoted $30,000 from Solar City for a 5.5kw system, did the job myself for about $12,000.

I went with 4th gen enphase m215 and 24x230watt panels.

Enphase inverters, Enphase gateway(monitoring) and all hardware to mount all 24 panels on the roof cost $6000 from Renvu. The panels cost about $3600 (off craigslist). Copper wire, permits, labor, all other small things were around $2400. Thats 12k. Add another 1000 for things I forgot. Puts me in at 13k. Minus 30% govt rebate leaves me at 10k. This is conservative, I am actually going to be closer to 9k

Took me and a retired electrician/general contractor one day to mount the framing on the roof. One day to run the wiring through the attic etc and half day to mount the panels. Thats 5 man days. Could have been done in 4 if we didnt waste so much time hanging out.

My project is conisdered complex because:
1- Panels are going on the 2nd story
2- 3 roof planes are having panels installed (8x8x8)
3- Theres a lot of distance from the panels to the electric panel (150 feet of wiring, drilling through walls and fishing wire, etc)
4- Attic vents, bathroom vents and sewage vents all had to be relocated to make space for the panels

It took me about a month of using youtube, reading forums etc. to get confident in my knowledge to move foward with the work.

Now I have enough power for my home and for 50 miles of commuting daily. Not only am I driving on electric power... I am driving on pure Sun Power

If you are at all handy and like to educate your self and like to learn new things then you should have no problem doing it yourself. If you have lots of $$ and you want worry free "I came home after work and theres a solar system on my roof"... then go with SolarCity/etc.

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More power to you my man !

How would you value 5 man days though as in $/hour ?