What do you wish you knew about solar before making the decision

[homelesshobbit]

If you knew it, would you still do it? I am at the last stage before signing the agreement and waiting on the HOA. I got 2 companies to quote and I decided to go with Sunstore. They then gave me 2 proposals and I chose the cheaper one: Canadian Panels instead of Sunpower panels. It will be 7.02 kw ($3.75 per watt) 78% of my current electric usage. I will finance through Dividend Solar and the fed/state tax will go into the loan once received; leaving me to pay out of pocket for $11,800 at 6.75%. Does this seem like I am making the right choice, or is there anything I am not considering?

27 Canadian 260w
1 SMA 7000TL

[bcroe]

Default What do you wish you knew about solar before making the decision

If you knew it, would you still do it?

I would have liked to know more about the influence of weather, patterns of shading over
a year, the removal of snow, and the ease of seasonable tilting. Yes I'd do it. Bruce Roe

[homelesshobbit]

I would have liked to know more about the influence of weather, patterns of shading over
a year, the removal of snow, and the ease of seasonable tilting. Yes I'd do it. Bruce Roe

do you think with me being in South Carolina and having little to zero snow, I'll be ok in that regard...Ohh and no shade either.

[bradykp]

is that your only financing option? that's not bad, but you can get better rates on other types of loans

[bcroe]

do you think with me being in South Carolina and having
little to zero snow, I'll be ok in that regard...Ohh and no shade either.

That is 2 down. Bruce Roe

[azdave]

My panels all face due south and I maxed out my roof area in that direction. I would have liked to have understood better how adding additional panels facing east and west might have increased my capacity without needing a bigger inverter by gathering more light early and late in the day when the south panels are not at full output.

[skipro3]

Things I wish I knew;
That a 5kW solar installation will never get close to 5k output. Mine puts out at best 4200 watts AC peak on a cloudless peak summer day for a few minutes before heading back down again. Thinking I was getting screwed over, I opened a membership on PVOutput and viewed my data from my Solaredge inverter and my Rainforest Eagle. The inverter gives me generation, the Rainforest gives me load as well as upload/download to the utility company.

The best part of PVOutput was that I could overlay any 5kW system out there also on the site on to my generation and I could see that my system was not only comparable to any others, but in most cases, mine outperformed others. (The beauty of living in a rain-free California)

I would have sized up a couple panels based on this knowledge. I was sold a system they told me would cover my 9150kWh annual use and I'm thinking I'll be lucky to get 8000kWh.

For the past week, full sun/no clouds, I get between 29kWh and 31kWh output for a full day. My system starts making power by 6:30am and goes into night mode by 8pm. Comparing my installation with comparably sized systems on PVOutput, this is what I can realistically expect.

[sensij]

I would have sized up a couple panels based on this knowledge. I was sold a system they told me would cover my 9150kWh annual use and I'm thinking I'll be lucky to get 8000kWh.

Perhaps you can take some solace in the fact that frequently, the most cost-effective array will not cover 100% of consumption. Especially with a $10 / mo minimum charge coming down the pike, under a tiered plan, you will end up paying for the last few hundred kWh even if you generate them.

PG&E has TOU plans that may be worth looking at, as well. The E-6 plan is hella complicated, and I've been working on building it into a spreadsheet but progress is slow. If you download and analyze your prior year's consumption, you may find that by switching to TOU you can offset more consumption (in kWh) than what you actually generate. More TOU plans will be coming out over the next few years, so even if what is available now doesn't work for you, keep an eye on it, because a new one might.

[Tommygun45]

Things I wish I knew;
That a 5kW solar installation will never get close to 5k output. Mine puts out at best 4200 watts AC peak on a cloudless peak summer day for a few minutes before heading back down again. Thinking I was getting screwed over, I opened a membership on PVOutput and viewed my data from my Solaredge inverter and my Rainforest Eagle. The inverter gives me generation, the Rainforest gives me load as well as upload/download to the utility company.

The best part of PVOutput was that I could overlay any 5kW system out there also on the site on to my generation and I could see that my system was not only comparable to any others, but in most cases, mine outperformed others. (The beauty of living in a rain-free California)

I would have sized up a couple panels based on this knowledge. I was sold a system they told me would cover my 9150kWh annual use and I'm thinking I'll be lucky to get 8000kWh.

For the past week, full sun/no clouds, I get between 29kWh and 31kWh output for a full day. My system starts making power by 6:30am and goes into night mode by 8pm. Comparing my installation with comparably sized systems on PVOutput, this is what I can realistically expect.

You are the first person I have seen who is getting lower than they were promised, but I am quite new at this. Are you sure there isn't something wrong with your system? What does pvwatts have to say? What kind of panels are you using?

[skipro3]

I just think it's kind of misleading;
Systems are sold on the amount of their production, so I was told. Went over all my use for the past 5 years and the salesman said this was the right size for 100% offset.

I do have 'wiggle room' with some conservation efforts. Yesterday I replaced my garage fridge with one that uses 1/3 the power. It will pay for itself in 40 months. I'm going LED on the lights and should be rolled over to them within a few months.

Current TOU isn't equitable for my usage. At least not right now. I LOVE my air conditioning!!

[sensij]

Whoa, PG&E does the rate comparison for you? That is fantastic... but how are they accounting for the solar production, for which you don't have much history?

[skipro3]

As far as PG&E is concerned, I have no solar production. They have yet to offer me PTO. I'm allowed to generate for 'testing' purposes. My definition, since they don't provide one, is to perform a burn-in test of what ever duration they take to grant said PTO.

PG&E offers LOTS of interesting stuff on my account pages. Here is an example showing that I already have a smart meter and that it records both To Grid and From Grid;



I imagine that I won't get credit for the excess I'm pushing out to them, but at least I'm offsetting my realtime use from my panels to my load.
And, I'm burning in my system. For testing purposes...

[skipro3]

You are the first person I have seen who is getting lower than they were promised, but I am quite new at this. Are you sure there isn't something wrong with your system? What does pvwatts have to say? What kind of panels are you using?

Every quote I've heard quotes the DC panel watt total based on ideal conditions. Pretty unrealistic. What duped me was the Solaredge Site Designer software. The program allows a person to build their system using Solaredge inverters and optimizers, then predicts the generation month by month. It predicted that my installation would produce 8,520kWh for the year. That's an average of 23.3kWh a day, everyday, 365 days a year. Seeing as I only generate an average 30kWh a day this time of year, I figure I won't come within 1000kWh of that. I may be wrong but I'm basing this on my lat and long, array azimuth and tilt angle of the panels.

PVWatts says my solar size will generate 7,491kWh a year. Now that I can agree with and is realistic. (Which is why I wish I had known this before I made this decision)
This is 12% less than the SolarEdge Site Designer said I would get. 12% is 1.92 additional panels of my 315w panels. My inverter can easily handle that, I would have happily paid for the correct sizing so I don't get why my solar company came in so low. Perhaps he thought I cared too much about price and wouldn't know the sizing was off so much from what I made abundantly clear.

I"m using 16 panels of SunWorld Pro Series XL 315 Mono (16 x 315 = 5040), SolarEdge inverter with optimizers.

The panels are 72 cells per panel, larger than the standard 60 cell panels. Went with these because of the USA presence of Solarworld and with the larger panels, less cost. I chose the Solaredge inverter/optimizers over the micro inverters because I just don't see how any inverter can operate every day for 25 years, especially the capacitors. This way, I get the advantage of individual panel isolation for generation with the ease of serviceability.

[sensij]

Every quote I've heard quotes the DC panel watt total based on ideal conditions. Pretty unrealistic. What duped me was the Solaredge Site Designer software. The program allows a person to build their system using Solaredge inverters and optimizers, then predicts the generation month by month. It predicted that my installation would produce 8,520kWh for the year. That's an average of 23.3kWh a day, everyday, 365 days a year. Seeing as I only generate an average 30kWh a day this time of year, I figure I won't come within 1000kWh of that. I may be wrong but I'm basing this on my lat and long, array azimuth and tilt angle of the panels.

Using PVwatts for your array, with the size and orientation listed in your PVOutput setup, the model shows 8739 kWh annually.

Here is a typical july day from the PVwatts model, overlaid with your actual data from today, and from a couple days ago:

Skipro.GIF

That model was run using premium panels, roof mount, 8% loss. You can see that the morning and mid-day peak are more or less in line with the model. The afternoon underperforms, suggesting some loss of solar resource, or perhaps thermal effects (or maybe bad synchronization between the actual and model timestamps, and its really the morning underperforming, not afternoon). Anyway, the model shows 8739 kWh generated, so if the difference between the model and actual output seen here is representative of the entire year, that would scale to 8123 kWh annually (subject to weather, of course). If it really is loss of solar fraction due to something structural, it may get better or worse throughout the year and it is harder to estimate from what you have.

Edit:
You can see this same kind of analysis on my array, if you'd like.

[skipro3]

Thanks for doing that for me! Stop by to pick out a beer from the fridge in the garage anytime.

I agree that the solar installation I have works as designed. I just wish the salesman would have been more forthcoming in making sure I understood that this was probably not going to cover 100% of my current use.

I have reason to want 100% coverage; I'm expanding my power requirements soon. I'm putting in a well next. Then a conversion of the attic room to an apartment for a future live-in health care provider. Oh, and a hot tub! California baby!