Lowest Achievable CPW Installed @10KW (rooftop)?

[sunnyguy]

Anyone have any advice on POCO rate plans for APS?

If you're on a demand charge plan once the sun goes down and before 7pm you're going to get hit with probably a similar demand charge as if you didn't have solar.

If you're not on a demand charge plan you get hit with a monthly solar fee of $5 (but they are raising it to $20).

If someone can post an example APS bill that would be great.

[sunnyguy]

Check out something called PVWatts on the net. Data for Edmonton, AL is in that database.

It's an estimating program from the U.S. NREL and may be of help in answering your questions. Spend 20 min. reading the help/info screens before making a few runs. With a bit of practice, and reference to the help screens, you'll probably get a quick education. Then, download the hourly output option to excel and after some spreadsheet finagling you'll get a decent estimate as to how much production to expect for your location.

Thanks for the pointer. I've used pvwatts but never noticed the hourly download data.

According to that, a SE oriented system will generate 48.3% of its energy after 12pm and a SW oriented system will generate 63.8% of its energy after 12pm.

[J.P.M.]

Check out something called PVWatts on the net. Data for Edmonton, AL is in that database.

It's an estimating program from the U.S. NREL and may be of help in answering your questions. Spend 20 min. reading the help/info screens before making a few runs. With a bit of practice, and reference to the help screens, you'll probably get a quick education. Then, download the hourly output option to excel and after some spreadsheet finagling you'll get a decent estimate as to how much production to expect for your location.

[sunnyguy]

Anyone have any data on average % of total production that happens after 12pm?

Based on some back of the envelope calculations, if the system can produce 60% of its power after 12pm then 1W of solar generates approx $0.29 worth of electricity in a year based on my power bill.

So a 5 year payback is doable if cost per watt installed is $2.20 before tax credits.

That means the system should favor a more western orientation.

[sunnyguy]

Is the best thing to measure the solar radiation at all the possible locations at different times of the day using a meter? Any affordable/reliable ones?

[sunnyguy]

Here's another view with 54 panels possible locations.

http://i.imgur.com/mCeUo0U.png

Right just just figuring out placement options. Is it possible to place panels/racking at 45deg to rafter orientation? Comments welcome.

[sunnyguy]

1.) When it's the only option.

2.) When it's a better option than all the others.

20% less output than south facing sounds about right. The economics will probably be in about the same neighborhood depending on a lot of things like usage patterns and POCO tariffs and particulars.

One way to get the 20% back: Lower consumption by 20%. It's cheaper than solar.

It was actually 20% less than SE/SW since those are the options. As you can see, there is a lovely open NE section of roof for panels.

Here is my roof. Street side is at the bottom (SW) side.

http://i.imgur.com/slFiAdc.png

Here I was able to fit 36 panels:

http://i.imgur.com/6AR3y3f.png

Anyone have comments about shading due to roof geometry ? Roof pitch is 18.4deg.

[J.P.M.]

Anyone have any advice on when to consider putting panels on a NE facing roof? PVWatts says it produces 20% less energy so 20% longer payback period.

1.) When it's the only option.

2.) When it's a better option than all the others.

20% less output than south facing sounds about right. The economics will probably be in about the same neighborhood depending on a lot of things like usage patterns and POCO tariffs and particulars.

One way to get the 20% back: Lower consumption by 20%. It's cheaper than solar.

[sunnyguy]

Anyone have any advice on when to consider putting panels on a NE facing roof? PVWatts says it produces 20% less energy so 20% longer payback period.

[sunnyguy]

I was just about to suggest that you look up some of HXguy's posts. He ran into a lot of issues with an installer, and basically was left with re-doing the project on his own. He's got a 78-page thread that is informative, and strangely enthralling at times - sort of watching a train wreck in progress. In the end, (and to his credit) he got it all sorted out.

After watching a lot of YouTube videos, I had considered DIY on my project coming up in May but honestly, I just don't have the time and especially after reading just how easy it is for a PV project to go wrong; i figured it was best just to hire someone that knows what they are doing. Still, I've spent a lot of time researching solar projects on my own and will be very much involved in my installation. Someone told me that a many folks are "blissfully unaware" and merely take a leap of faith by trusting everything to the installer. Considering that HXguy's "guy" came with good references in the beginning, if he wasn't involved - there's a good chance his house may have burned to the ground due to the installer's incompetence.

Another thing to keep in mind (that I've learned from hanging out on this site) is chasing the cheapest deal at the expense of quality and / or a fly-by-night installer. If a quote seems too good to be true; it probably is. Where I live (Edmonton, Canada), we don't have any subsidies so shopping around is a necessity. PV prices are roughly double than that in the US, so for those reasons; if I wanted to keep my ROI reasonably short I needed to find low cost panels. I picked up 9.45kW of used SunPower panels at under $0.45 per watt I also found an installer that is as excited as I am in having my project turn out as best as possible. His firm is relatively new but he's an engineer and has a master electrician on staff. My project is his largest so far, and he'll be using it as his reference installation to show other customers. In the last two months, he's answered at least 50 emails from me and has provided several possible PV designs free of charge.

Good luck!

Yes that is interesting that he had to do a lot of DIY even though he planned not to. And he didn't seem to have any trouble getting the inspections done without the installer present. However the installer did at least get all the permits for him.

[sunnyguy]

I installed my 10.92kw system for $9,350 after tax credits and incentive. Cost of all materials and wiring was $16,500 from our supplier, and I paid my helper $300 for a weekend. There are no permits or inspections required here, and all you need to apply for is a Certificate of Public Good, which they never deny you.

Ben

That sounds pretty good. I'm going to send you a PM for more details. Thanks.

[Ben25]

Often you get what you paid for

Yes. A very well installed system done by a reputable company and experienced installer.

[russ]

Often you get what you paid for

[Ben25]

I installed my 10.92kw system for $9,350 after tax credits and incentive. Cost of all materials and wiring was $16,500 from our supplier, and I paid my helper $300 for a weekend. There are no permits or inspections required here, and all you need to apply for is a Certificate of Public Good, which they never deny you.

Ben

[oilerlord]

I'm going to send a post to HX_Guy for some insight on local issues.

I was just about to suggest that you look up some of HXguy's posts. He ran into a lot of issues with an installer, and basically was left with re-doing the project on his own. He's got a 78-page thread that is informative, and strangely enthralling at times - sort of watching a train wreck in progress. In the end, (and to his credit) he got it all sorted out.

After watching a lot of YouTube videos, I had considered DIY on my project coming up in May but honestly, I just don't have the time and especially after reading just how easy it is for a PV project to go wrong; i figured it was best just to hire someone that knows what they are doing. Still, I've spent a lot of time researching solar projects on my own and will be very much involved in my installation. Someone told me that a many folks are "blissfully unaware" and merely take a leap of faith by trusting everything to the installer. Considering that HXguy's "guy" came with good references in the beginning, if he wasn't involved - there's a good chance his house may have burned to the ground due to the installer's incompetence.

Another thing to keep in mind (that I've learned from hanging out on this site) is chasing the cheapest deal at the expense of quality and / or a fly-by-night installer. If a quote seems too good to be true; it probably is. Where I live (Edmonton, Canada), we don't have any subsidies so shopping around is a necessity. PV prices are roughly double than that in the US, so for those reasons; if I wanted to keep my ROI reasonably short I needed to find low cost panels. I picked up 9.45kW of used SunPower panels at under $0.45 per watt I also found an installer that is as excited as I am in having my project turn out as best as possible. His firm is relatively new but he's an engineer and has a master electrician on staff. My project is his largest so far, and he'll be using it as his reference installation to show other customers. In the last two months, he's answered at least 50 emails from me and has provided several possible PV designs free of charge.

Good luck!