Ground-mount 9Kw solar install beginning today

[7acres]

Hi all,
Today's the day. They dropped off a Bobcat with auger attachment an hour ago. Monday they dropped off the racking and inverters. They're aiming to have the install completed by the end of the week.

A rundown of the grid-tie install:
* 8.96Kw from 32 Canadian Solar panels
* Schletter ground mount racking hardware
* 2X SMA SunnyBoy (SB 5.0-US) 5000W Inverters
* Oversized wire, conduit and combiner creating potential to add another 5kw in the future.
* Anti-theft fasteners

Here's today's progress from a half day of work:

 

[semipro]

Congratulations. Thanks for posting. Until we get our I'm enjoying installs like this vicariously.

 

[jebatty]

Congrats, also. Except for string inverters (mine are micros), your system is a lot like mine, now in use for just over 3 years. Over-sizing the wiring is an excellent choice. I did the same, started with a 6.9kw system, then expanded to 12.4kw using wiring already installed. Sunny day yesterday after nearly a month of heavy cloud cover, typical for Nov-Dec, and 31kwh produced,

 

[mol1jb]

Congrats, also. Except for string inverters (mine are micros), your system is a lot like mine, now in use for just over 3 years. Over-sizing the wiring is an excellent choice. I did the same, started with a 6.9kw system, then expanded to 12.4kw using wiring already installed. Sunny day yesterday after nearly a month of heavy cloud cover, typical for Nov-Dec, and 31kwh produced,

31 kwh in a day?

 

[jebatty]

Yes, that was 31 kwh on Dec 14, very close to the shortest day of the year, and the sun only rising to about 19* above the horizon. Today was sunny also, and 32 kwh. My all-time high daily production so far has been 89kwh, that occurring on April 22, 2015. Total annual production is running right around 15-16 Mwh

 

[7acres]

Today the crew struggled to get the 24" auger to go any deeper than about two feet deep before hitting granite bedrock. The auger Sunbelt rented them wasn't sharp or something. I dug 35 holes right into the same granite with a bobcat/auger setup just like they had 6 years ago when the orchard went in. They will be bringing a jackhammer tomorrow.

After trying all 6 holes and getting the same result they changed tack and continued with the AC-side of the install.

 

[jebatty]

My Schletter mounts were installed in a meadow wetland, and core drills to 8' before gravel/sand was reached to provide a firm foundation for the concrete footings.

 

[mol1jb]

That is some cool tracking software. Are you still grid tied with your setup?

 

[jebatty]

Still grid tied - yes. When economical kWh energy storage becomes available, I seriously would consider going off grid. Below is the graph for the 89 kWh day.

 

[mol1jb]

If you don't mind me asking what kind of cost is a set up like your run? I would love to get a solar system for our property but I don't think I can afford it currently.

 

[jebatty]

Cost is dependent on area labor rates, type of install, choice of components, permits and inspections required, etc. In my area a high quality ground mount system on a turn-key basis currently can be acquired for about $2.50 to $3/watt. So a 5,000 watt DC system would require a cash outlay of about $12,500 - $15,000 before the federal tax credit and other available incentives, which can be very substantial depending on your state and utility.

If your state has net metering and/or certain kinds of incentives, you especially have to look at a PV system not as a "cost" but as an investment, because it will produce a monetary value return as soon as it is operable which can recover your cash outlay quite quickly and then continue to add to your bottom line. Economic payback time therefore is variable, but investment return starts from day one. Depending on the financial analysis, it may be wise to obtain a home equity loan or other loan to get the needed cash because the rate of return on the system easily can be greater than the interest rate on the loan.

 

[peakbagger]

If you don't mind me asking what kind of cost is a set up like your run? I would love to get a solar system for our property but I don't think I can afford it currently.

Interestingly, the OP actually wasn't thinking about solar when he made a post about energy use and we encouraged him to look at solar. It turns out that the incentives for solar in his state are incredible and its probably the best investment he can make (I sure hope so, as I don't want to have egg on my face). There is 30% federal incentive that everyone gets but every state and possibly utility has different incentives and regulations that may or may not encourage solar. I would suggest going to this website and see what incentives apply specifically to you http://www.dsireusa.org/. You need to review the incentives and see if there is "net metering" and if so what the details are, as differing net metering rules may change the size of your system. Keep in mind that if in doubt the best investment is to spend money not to need to use electric power, typically every dollar spent on energy efficiency has far better payback that putting in PV.

One big caution is that there is an entire industry that has sprung up that is really a tax dodge for big investors that is hidden by folks desire to be green. These are big national firms that push creative financing options that you want to steer clear of. Effectively the many variations boil down to they get a long term attachment on your property where they get the vast majority of the benefits while giving you a small benefit that you could come to regret if you ever want to sell the house. Ideally you only would want to install a solar system on a house that you plan to keep long term. You would want to buy the system outright after making sure you have taken advantage of every incentive and if need be take a short term home equity loan out to pay the balance.

 

[mol1jb]

I appreciate all the info. It is definitely something I want to research more. I have only lived in our house one year but we hope to live here for atleast 15+ years. It is a large city lot, just over 1/2 acre. With regards to placement of roof vs ground mounted, is there a recommendation one way or the other? Both my roof (rear of house faces south) and yard have good south facing options.

 

[peakbagger]

Roof mount is typically less expensive than ground mount as long as there is no shading, Vent pipes and chimneys can really impact production. Individual microinverters on each panel can help with the shading issue but increases the over all cost of the system. One thing to factor in is generally with roof mounts, its highly recommended that you replace the roof shingles before you install the panels so you can delay the inevitable of having to remove the panels to replace the shingles.

 

[mol1jb]

Roof mount is typically less expensive than ground mount as long as there is no shading, Vent pipes and chimneys can really impact production. Individual microinverters on each panel can help with the shading issue but increases the over all cost of the system. One thing to factor in is generally with roof mounts, its highly recommended that you replace the roof shingles before you install the panels so you can delay the inevitable of having to remove the panels to replace the shingles.

Thanks for the info. Makes sense with the roof replacement. My shingles have a few years left and we will be replacing with metal. Definitely interesting

 

[7acres]

Yeah, my install is roughly $35k. Then Federal will cover 30%, State 25% and the utility will cut me a check for $8,960 ($1 per watt). So after all the rebates, etc it will have cost us a net of about $8,500 for the install. It will pay for itself in under 5 years. Then it's just pure savings from that point on.

 

[7acres]

The crew returns Monday and will be here all week. Probably finishing it up by the end of the week. We can't wait to see it completed!

I also can't wait to get my first electricity bill with the house on solar

 

[mol1jb]

Yeah, my install is roughly $35k. Then Federal will cover 30%, State 25% and the utility will cut me a check for $8,960 ($1 per watt). So after all the rebates, etc it will have cost us a net of about $8,500 for the install. It will pay for itself in under 5 years. Then it's just pure savings from that point on.

Wow that is a great price for install and even better return. Roughly how many kwh do you use per month?

 

[7acres]

From memory the range goes from 1000Kw/hrs in the Winter (wood stove/no heat pump at all) and 2400Kw/hrs in the Summer (Air Conditioning running full tilt). The average seems to be 1450Kw/hrs.

 

[mol1jb]

From memory the range goes from 1000Kw/hrs in the Winter (wood stove/no heat pump at all) and 2400Kw/hrs in the Summer (Air Conditioning running full tilt). The average seems to be 1450Kw/hrs.

Very cool. And how much is your setup estimated to produce per month?

 

[7acres]

Oh, how does the math work? 9 x Hours of Sun in the day. Then multiply that by 30 days. Then multiply that by the efficiency rating. Something like 87%.

It's a bell curve from January to December. The least power produced in Winter and the highest production in Summer.

Somebody please correct me here. I'm sure my math is off somewhere.

 

[peakbagger]

Easiest way to figure out performance is to look for PVWatts on the internet. Enter your location, array size, the type of mount and panel angle plus its location relative to south and the project gives you a generally conservative monthly and yearly production number based on your local weather conditions. Works good except if the panels are covered with snow in the winter.

I have a total of 4.6 KW in three different types of array and generate more power than I use every year. I carried 2000 KWH into this winter which I use to run a mini split to heat my house when the temps are over 30 degrees.

 

[Where2]

The math is entirely complicated. When the sun first peeks over the horizon in the early morning, it is not nearly as intense as it is at mid-day because of all the air and particulates in the atmosphere. At mid-day, the sun is punching through the least amount of atmosphere and particulates to hit the panels, and the rays of the sun are hitting the panel (hopefully) fairly close to perpendicular.

Much like shining a flashlight perpendicular to a wall will produce a smaller, much more intense concentration of light than shining it up from the base of the wall where the light beam washes along much more wall area, yet produces less intense light, solar panels work much better with direct sunlight from overhead. Overcast days where there is lots of scattering of the sunlight, your production will be much lower than a cloudless clear day. With my system, I can tell you when a cloud passes over.

PVWatts 2 certainly gives a good measure of performance. You can also get a "ball park" for a given area by searching through maps like the one Enphase has that shows "public enphase PV system" production numbers. I watched the daily production numbers on an installation about a mile from my house for close to a year while I pieced together the parts to install my own array. I'm presently watching an enphase system 2,000 miles away from my array #1 (near our summer farm property) to get a feel for what the 4.6kW array I'm designing will produce in a vastly different climate from where array #1 is.

 

[peakbagger]

The math is entirely complicated. When the sun first peeks over the horizon in the early morning, it is not nearly as intense as it is at mid-day because of all the air and particulates in the atmosphere. At mid-day, the sun is punching through the least amount of atmosphere and particulates to hit the panels, and the rays of the sun are hitting the panel (hopefully) fairly close to perpendicular.

For those in cold climates, the outdoor air temp also factors in, PV panels like cold temps (up north my panels will actually put out more watts than the panel rating on very cold days (-10 or below). Hot temps reduce the output per panel but usually the logner days in summer offset the reduced performance. Snow on the ground also makes a difference as it will reflect more sun on the panels. Panel angles also factor in, my pole mount has an adjustable angle, I adjust mine 4 times a year to optimize the angle. Vermont has an odd incentive system that encourages the installation of solar arrays that "track" the sun. they adjust their sweep left to right and the angle up and down, these systems can put out 30% more power than a fixed array. The reason most folks don't use trackers is the initial cost is steep. Unless there are incentives to offset the initial cost its far better to install more panels as they are much cheaper. (they are pretty interesting to watch over the course of the day).

 

[mol1jb]

Interestingly, the OP actually wasn't thinking about solar when he made a post about energy use and we encouraged him to look at solar. It turns out that the incentives for solar in his state are incredible and its probably the best investment he can make (I sure hope so, as I don't want to have egg on my face). There is 30% federal incentive that everyone gets but every state and possibly utility has different incentives and regulations that may or may not encourage solar. I would suggest going to this website and see what incentives apply specifically to you http://www.dsireusa.org/. You need to review the incentives and see if there is "net metering" and if so what the details are, as differing net metering rules may change the size of your system. Keep in mind that if in doubt the best investment is to spend money not to need to use electric power, typically every dollar spent on energy efficiency has far better payback that putting in PV.

One big caution is that there is an entire industry that has sprung up that is really a tax dodge for big investors that is hidden by folks desire to be green. These are big national firms that push creative financing options that you want to steer clear of. Effectively the many variations boil down to they get a long term attachment on your property where they get the vast majority of the benefits while giving you a small benefit that you could come to regret if you ever want to sell the house. Ideally you only would want to install a solar system on a house that you plan to keep long term. You would want to buy the system outright after making sure you have taken advantage of every incentive and if need be take a short term home equity loan out to pay the balance.

Are you able to post the link to that thread? Id love to read through it.