Small home DIY install in Ohio

[SunEagle]

It would be hard to imagine how the DIY grid-tie install the OP has described could exceed $3 / W. With the parts mentioned, it could be substantially less than $2 / W.

Ah. I missed that in the OP first post. Yes I can see the price of a DIY being that low and having a much quicker payback then one for me.

[sensij]

It is just that I am using about 15000kWh per year with a cost of ~ $0.12/kWh and unless I can get an installed cost down below $3/watt before the FED rebate I get an ROI of around 8 years so 6 years seems pretty short even at $0.13/kWh.

It would be hard to imagine how the DIY grid-tie install the OP has described could exceed $3 / W. With the parts mentioned, it could be substantially less than $2 / W.

[SunEagle]

Or another way to check it out as long as the OP is using SAM: Change the # of years in the analysis until the "real LCOE" = $0.13. Not the same number as current per kWh cost, but maybe a more realistic way to look at years to cost effectiveness than the simplistic initial cost /current annual electric bill method. Besides being a pretty good tool for sizing, SAM's also a pretty good tool for learning stuff, in this case about ways to estimate cost effectiveness and something of process economics. One of several reasons to use SAM over PVWatts.

It is just that I am using about 15000kWh per year with a cost of ~ $0.12/kWh and unless I can get an installed cost down below $3/watt before the FED rebate I get an ROI of around 8 years so 6 years seems pretty short even at $0.13/kWh.

[J.P.M.]

Out of curiosity. With your estimated 12000 kWh usage and $0.13/kWh costs what did you determine you system installed $/watt would be to get that 6 year payback?

Or another way to check it out as long as the OP is using SAM: Change the # of years in the analysis until the "real LCOE" = $0.13. Not the same number as current per kWh cost, but maybe a more realistic way to look at years to cost effectiveness than the simplistic initial cost /current annual electric bill method. Besides being a pretty good tool for sizing, SAM's also a pretty good tool for learning stuff, in this case about ways to estimate cost effectiveness and something of process economics. One of several reasons to use SAM over PVWatts.

[SunEagle]

I have done a bit of background research on my energy usage. I had an energy audit done last month helping me understand my heating/cooling/insulation. Everything was pretty good. Furnace and water heater are natural gas. All appliances are new Samsung units, energy star, etc. I also have a smart utility meter which features a solid smart phone app. Lets me know my instantaneous usage and records daily usage too. Super useful. All home bulbs have been updated to LED. My thermostat is an Ecobee3 smart unit, that automatically lowers temps when we leave. I havent gone to any extremes, but I believe solar is the

One of the biggest reason I want solar is because I drive a Volt and use at least 10kWh a day for that. In general I have been using 1100kWh a month for the winter and expect closer to 900kWh this spring. Annually (which is what matters for co-generation vs net metering in my area) I should be between 10000-12000 kWh. I am looking at system that produce 6000-8000 kWh annually. If I over produce then I will get my wife a PHEV too. No TOU rates in my area, but I am at about $0.13/kWh right now. My payback time reported for a self install have been between 4-6yrs using SAM. Early on I also used Helioscope to calculate annual energy.

Out of curiosity. With your estimated 12000 kWh usage and $0.13/kWh costs what did you determine you system installed $/watt would be to get that 6 year payback?

[Nut&Volts]

I have done a bit of background research on my energy usage. I had an energy audit done last month helping me understand my heating/cooling/insulation. Everything was pretty good. Furnace and water heater are natural gas. All appliances are new Samsung units, energy star, etc. I also have a smart utility meter which features a solid smart phone app. Lets me know my instantaneous usage and records daily usage too. Super useful. All home bulbs have been updated to LED. My thermostat is an Ecobee3 smart unit, that automatically lowers temps when we leave. I havent gone to any extremes, but I believe solar is the

One of the biggest reason I want solar is because I drive a Volt and use at least 10kWh a day for that. In general I have been using 1100kWh a month for the winter and expect closer to 900kWh this spring. Annually (which is what matters for co-generation vs net metering in my area) I should be between 10000-12000 kWh. I am looking at system that produce 6000-8000 kWh annually. If I over produce then I will get my wife a PHEV too. No TOU rates in my area, but I am at about $0.13/kWh right now. My payback time reported for a self install have been between 4-6yrs using SAM. Early on I also used Helioscope to calculate annual energy.

[J.P.M.]

JPM brought up a good point on page 1 - load calcs What he is referring to is to make sure you understand exactly if solar makes sense for your home.

Assuming you have not already done this (and if you have - great) is to step back and understand your current energy usage with the goal of reducing your current usage by energy savings. Start by getting the historical usage from your PoCo (hopefully you can just download this online) and continues by looking at everything that uses electricity in your home and understand how much is uses and if there are easy ways for you to reduce that usage. It includes things like weatherstripping and sealing of openings. Looking at how the big uses of energy can be reduced. This can be a balancing act between lifestyle choices and energy cost but any savings or repairs you find will give you immediate payback.

Then once you feel you have a realistic understanding of your current/historical usage and you feel that you have reduced the usage as much as your lifestyle dictates is to then understand what solar can do for you. This starts with knowing the rate programs for solar offered by your PoCo. Software such as SAM (which is free) can really help you with "what-if" type of questions to understand how long it will take for your investment to pay for itself. Without this process you have no idea if putting the effort into installing a solar system is even worth it to you.

I'd respectfully add:

Having worked with POCO rates and SAM for some time now, I'd caution to be careful to confirm the rates that SAM uses. My experience is that, in the past, SAM's rates were generally incomplete and inaccurate. More recently, things w/the SAM rates seem to have improved with respect to accuracy, but they are far from complete, at least with respect to what my POCO is doing and what SAM thinks. Example: SAM still does not have my tiered rate daily allowance correct which throws everything off. T.O.U. rates as SAM uses them to be a better fit than before.

I know a bit, but not as much about other CA POCO rates, and things look similar with them, but I could be wrong on that. In any case, caution may be advised on trusting SAM's bill estimating accuracy.

[tyab]

JPM brought up a good point on page 1 - load calcs What he is referring to is to make sure you understand exactly if solar makes sense for your home.

Assuming you have not already done this (and if you have - great) is to step back and understand your current energy usage with the goal of reducing your current usage by energy savings. Start by getting the historical usage from your PoCo (hopefully you can just download this online) and continues by looking at everything that uses electricity in your home and understand how much is uses and if there are easy ways for you to reduce that usage. It includes things like weatherstripping and sealing of openings. Looking at how the big uses of energy can be reduced. This can be a balancing act between lifestyle choices and energy cost but any savings or repairs you find will give you immediate payback.

Then once you feel you have a realistic understanding of your current/historical usage and you feel that you have reduced the usage as much as your lifestyle dictates is to then understand what solar can do for you. This starts with knowing the rate programs for solar offered by your PoCo. Software such as SAM (which is free) can really help you with "what-if" type of questions to understand how long it will take for your investment to pay for itself. Without this process you have no idea if putting the effort into installing a solar system is even worth it to you.

[ButchDeal]

I need to look into these rapid shutdown boxes a little to see if they're worth it.
.

They are required by code. Micro inverters and solaredge have the feature built in though.

[Nut&Volts]

I need to look into these rapid shutdown boxes a little to see if they're worth it.

You're probabaly right about the south/west. I should just do it. It's a 10%+ difference annually. Black panels should look good on that roof.

[ButchDeal]

Why don't you install south / west instead of east /west? You would have more production

[sensij]

If you are putting 10 of the Hanwha Solarone 240's East and 10 West, each at 30 deg, you could consider the SB 3.8 -1SP, for ~$1400, plus rapid shutdown if needed for 2014 NEC, is another $450. The Fronius Primo 3.8 looks like it would be ~$150 less than SMA, rapid shutdown isn't much cheaper though if needed.

For hardcore savings, Renvu has the transformer based SMA SB4000US-10 listed in their weekly specials for $567.

[Nut&Volts]

Having the DC inside the home without conduit. When you go to a String inverter you combine them on the roof then inside of conduit all the way to the DC disconnect.
You would have to have the micro inverter inside the conduit.
And talk about a lot of penetrations in roof.

What PV modules are you using with this example? If you are still looking at the CS6U-345M for a 6.9kw system, then you should be looking a larger SolarEdge (SE5000 maybe) inverter and the P400 optimizer.

Thanks for pointing out that issue with the in attic micro/PV wire. Bummer.

My above example doesn't change no matter what panel you use. With the SE5000 ($1200) and P400 ($55*20) you make the cost breakdown even better for micros

APS-YC500i - 10 - 5480W - $1780
Solaredge - 20+1 - 5000W - $2300

Anyone have a better string inverter setup to suggest?

Here is my west roof and south roof at 6pm today

March 16, 2017 at 0556PM.jpg
March 16, 2017 at 0556PM (1).jpg

And some images with panels rendered in place
East_West.JPG


South.JPG

The big long stems are for box location, etc. Ignore them

[J.P.M.]

Yes your are very right about the south facing and that was the first place I considered putting them. I have used Helioscope and now I am using the NREL SAM program to test different layouts. Putting the same system on each roof I get the following breakdown, South=100%, West=87%, East=82% output. These are all 27-30deg tilt and the south roof is at ~168deg azimuth.

I tried outlining my motivation in an earlier thread about why I am ok with the West/East roof. The added roof area allowed me to use more panels. Ordering older lower wattage panels in a pallet quanitity can greatly reduced my cost, meaning I could get more energy output for the same cost. And the East/West arrangement may potentially allow me to spend less on inverters.

Understood. Just my manic attitude about squeezing as much out of any application as the criteria allows. Aesthetics have a cost. So be it.

[ButchDeal]

I think extending the dc panel cables wouldn't be a problem. Just like running DC cable to a string inverter. But maybe the micros location would be a problem? Is that your concern?

Having the DC inside the home without conduit. When you go to a String inverter you combine them on the roof then inside of conduit all the way to the DC disconnect.
You would have to have the micro inverter inside the conduit.
And talk about a lot of penetrations in roof.

I keep coming back to this route, but can't find the cost advantage. Here's a breakdown for a 20 panel East/West System
Micros - APS YC500i - 548W - 10 need - $178 webosolar ($157+$21cable)
5480W AC max - $1780

Optimizers - Solaredge P300 - 20need - $50 ebay & SE3800HD - 1 need - $950 renvu
3800W AC max - $1950

What PV modules are you using with this example? If you are still looking at the CS6U-345M for a 6.9kw system, then you should be looking a larger SolarEdge (SE5000 maybe) inverter and the P400 optimizer.