How difficult is DIY Grid Tie? (newby)

[Twitchr]

Hi folks, apologize for the neive question, I just have a couple questions if I am going down the right path to DIY, and what more experienced people would suggest.

I'm convinced I want to do solar, but I'm sure if I am going to hit huge roadblocks after dropping a bunch of money. I was planning on hiring it all out, but the solar contractors that have come out feel like used car salesmen. After looking at the proposed systems, it appears less complex than what I had thought. I do not plan on doing battery backup.

I'm mostly concerned with the grid tie aspect, and inspections/permits. I have started going thru my utility (Consumers Energy in Michigan) portal to apply, and it lists contractor as a required field. My meter is on a barn (agricultural), and I have been told by some other farmers that Ag buildings are exempt from inspections, and as long as I have my livestock.in there I'm good. Researching that shows some truth to it, honestly I'm happy building everything to code anyway, but if no inspection could eliminate a hurdle than cool.

I guess my question for the forum is, should I be intimidated by the utility tie aspect and application to the power company?

Thanks for any responses.

Background: Tech Center electrician training for 1 year, rewiring a couple houses that I flipped, and Power Engineer day-job.

 

[Hedges]

Sounds like you have the knowledge and experience.
Does your permit office allow owner-builder? Ours do in California.
Utility probably wants signed off permit.

Do you have net metering? Will you be required to switch to a less advantageous rate plan? Know what you're getting into, and that they will pull the rug out from under you later. Some states have even implemented a photon tax.

I find physical effort of mounting properly rain-shedding brackets on the roof the most work. But when I do it myself, I'll be sure that with flashing it is more watertight than simply squirting caulk and screwing in lag screws.

I did my own ground-mount 20 years ago and will do a rooftop in the next year.

Some people use microinverter, easier design and takes care of RSD.
Decide what you may want in terms of battery backup in the future, plan the design and understand cost before committing to the grid-tie design.
Something like SolArk will cost extra up front but works batteryless, and 48V battery can be added later. I'm going to be using SMA Hybrid when it is finally available, but that will need expensive high-voltage battery.

 

[Twitchr]

Sounds like you have the knowledge and experience.
Does your permit office allow owner-builder? Ours do in California.
Utility probably wants signed off permit.

Do you have net metering? Will you be required to switch to a less advantageous rate plan? Know what you're getting into, and that they will pull the rug out from under you later. Some states have even implemented a photon tax.

I find physical effort of mounting properly rain-shedding brackets on the roof the most work. But when I do it myself, I'll be sure that with flashing it is more watertight than simply squirting caulk and screwing in lag screws.

I did my own ground-mount 20 years ago and will do a rooftop in the next year.

Some people use microinverter, easier design and takes care of RSD.
Decide what you may want in terms of battery backup in the future, plan the design and understand cost before committing to the grid-tie design.
Something like SolArk will cost extra up front but works batteryless, and 48V battery can be added later. I'm going to be using SMA Hybrid when it is finally available, but that will need expensive high-voltage battery.

Thanks for your comments, I do not know if my townhip allows owner-builder, but I will do some research.

My local utility does not do net metering. They will buy back surplus electric at wholesale rate (about 1/3 of what they charge for retail), and they only give you that back as credit towards your usage. You will never get a check from them. So i want to build a system that mostly matches my usage (calculating around a 7KW system).

We have south facing roof on the a barn with the meter on it, that has a brand new metal roof. Or I could do ground mount, I like the benefit of not having to mow around it, but could be talked either way.

I have gone back and forth on micro-invertors vs central, from what I'm gathering there are great options with both types. However, since my meter/main panel board are in a barn it is super dusty with hay and straw, and doors are always open so humidity changes all the time. Having electronics in there with fans concerns me, as everything in there gets a sticky layer of chaff on it.

One question I haven't been able to find the answer to is based around insurance. Will the solar panels on the building typically raise my proporty insurance costs vs a ground array?

 

[Hedges]

I asked if my insurance company if homeowner's policy covered ground-mount panels. They said no, and gave me a quote of several hundred $$, so I didn't take it. I don't think you have to address insurance, just do the install with permits and don't worry about $7000 worth of equipment.

You can get string inverters with 3R or 4x enclosure for outdoor use. Fans (if present) only run when hot. Glued on dust would be a problem. Outside could be better, depending on what blows there.

There are mounts that clamp rails to a standing seam roof, from Unirac and others.

What are your utility rates?
I put GT PV with string inverter hardware around $1.00 ~ $1.25/W, and amortized over 20 years $0.025 ~ $0.03/kWh.
Batteries would cost $0.05/kWh and up.
Cheaper I think to install 3x the wattage you need, get 1/3 of retail credit from utility and buy back for retail.
If your rates are $0.10/kWh that doesn't do much for you (so try to use power as you make it, shave the peaks and fill the valleys), but if you pay $0.20 and up then it is a win.

Do you have single (split) phase or 3 phase? What voltage?

 

[Twitchr]

I asked if my insurance company if homeowner's policy covered ground-mount panels. They said no, and gave me a quote of several hundred $$, so I didn't take it. I don't think you have to address insurance, just do the install with permits and don't worry about $7000 worth of equipment.

You can get string inverters with 3R or 4x enclosure for outdoor use. Fans (if present) only run when hot. Glued on dust would be a problem. Outside could be better, depending on what blows there.

There are mounts that clamp rails to a standing seam roof, from Unirac and others.

What are your utility rates?
I put GT PV with string inverter hardware around $1.00 ~ $1.25/W, and amortized over 20 years $0.025 ~ $0.03/kWh.
Batteries would cost $0.05/kWh and up.
Cheaper I think to install 3x the wattage you need, get 1/3 of retail credit from utility and buy back for retail.
If your rates are $0.10/kWh that doesn't do much for you (so try to use power as you make it, shave the peaks and fill the valleys), but if you pay $0.20 and up then it is a win.

Do you have single (split) phase or 3 phase? What voltage?

Good to know! I wasn't aware they made ones rated for outdoor use.

We pay .21/kwh, and during summer it's .27/kwh between 2-7pm. But, hearing from other people who have gone solar, they put up about what they use on average and have a power bill less than $10/month ($8 is for the meter). Over the last year, what I'm seeing is that I need about a 6KW system but I was planning on going 7kw to get room for growth.

We have single phase 240v 200 amp service.

 

[Hedges]

OK, put in about 20 kWh of panels (with multiple orientations, would fit well for 10kW to 14kW of inverters). You'll only use 1/3 of it, so over 20 years power costs $0.075 to $0.09/kWh but you can draw it back from grid any time of the day or night. You spend a nickel more for the PV power you do use, but still save a net dime or more by not buying from the utility.
If you add battery backup, the 3x capacity will help on cloudy days.

If you do put in just one 7kW (or 7.7kW, max on 40A breaker in 200A panel), over-panel with PV to at least 10kW, maybe 12 ~ 14kW depending on how panel voltage and current fits MPPT max limits.

I've been using older model Sunny Boys. I'm about to install one or more of these -41 models. They're being replaced with a hybrid "Sunny Boy Smart Energy" so I'll probably put in those too.

Discover the Sunny Boy 3.0-US - 7.7-US | SMA America

Discover the Sunny Boy inverter 3.0-US - 7.7-US ► PV performance optimization with SMA ShadeFix ► SMA's SunSpec certified shutdown device

www.sma-america.com

Discover the Sunny Boy Smart Energy | SMA America

The hybrid inverter at the heart of the SMA Energy System, with three backup options: Sunny Boy Smart Energy ► Discover now!

www.sma-america.com

Are you required to use UL-1741-SA (or -SB), Rule 21? If not, older model inverters from SMA or Fronius could work too.
My existing system was installed under older UL-1741, so I can replace with older inverters. New house, new system will need new models.

 

[k490]

I know what you mean by solar contractors they looking to make big bucks incredible what they charge some $3-5 a watt for a Grid tied system. I watched my neighbor get a 12kw system put in only took them 2 days didn't even work all day. I estimated the owner made $500-1000 an hour at least. If you price out a 14kw system grid tie kit for less, then $10k solar contractor charge you about $30k for that. You do get a federal tax credit also. In order to save money with a grid-tie only need to be using majority of that 12kw power during the time sun is on the panels. Here in Phoenix, we do in the summer AC running 24/7.

There are companies who will provide you with a civil engineer stamped plans for $1500 one example there are others. Simple grid tie with no battery is the lowest cost and simple to install.

If you're on a farm might be able to do a sun tracker system, it moves the panels keep the panels facing the sun. It does help.