So, this is all a fairly steep learning curve. As in all things there is shoddy work and bad advice abounding.
I am going to tell you again straight up, that if you don't have a good south facing roof unobstructed to the sun's rays, then forget it right there.
These East/West facing roof systems will never pay off. I know there a lot done and these marginal systems installed, but they should not be. Ethical companies will not sell you those.
Now, the first thing to understand is the NEC rules. The maximum power that the panels can deliver CAN NOT exceed 20% of the rating of your panel and electrical service. If you want to go higher then you have to instal a higher capacity electrical service, and may well have to pay for the utility to increase their infrastructure also. This makes it not worth it. So kept my original service.
The reason is that if you used the maximum draw your panel is rated at, and the panels are at maximum allowed then your service is actually handling 20% more power than spec. The NEC have granted that much 'wiggle room'. So I have a 200 amp service and so my max solar production can be no higher than 7.5 KW. So I have 20 panels that could max out at 7.6 KW, but that is within the what is allowed, but adding another panel would not be.
They will make you bring your service up to NEC 24, which essentially means SPD 1 surge protection at entry of your service to your home, and SPD-2 at all electrical panels.
Now I advise knowing your local electrical codes, and you will need to pull a building permit. Also contact your electrical service provider for any standards and codes they may enforce. In particular they will have questions about the phase locked loop systems involved to synchronize with their service. I did have trouble making our power company understand how my system achieved this, which surprised me. My first contact was in the pig dribble ignorant category. But once I got to talk to someone with more than one functional neuron and half a synapse, we got on swimmingly, and they were very helpful. The local electrical inspector was good enough to pay me a visit early in my planning stage. He told me he passes very few at the first inspection and two and three inspections is in the realms of the norm for him.
So I had mine installed by Blue Raven solar. After a little initial friction, a very good working relationship developed with their engineers.
Now you do need to stay involved and supervise a robust and neat installation. I stopped mine twice. By the third time they understood it was going to be my way, or the highway.
Now, these systems are actually quite simple. The panels are installed on the roof, and make sure you have a safe design. Also make sure your roof trusses are rated for the extra load. I still have a 100% load factor left after installation, but I went overboard with the truss design, as I wanted Florida hurricane spec.
Now each panel has it own inverter and a phase locked loop. Down below is the combiner, which synchronizes your system to the electrical service, and all the panel inverters synchronize to that.
The there is a fireman's switch so they can shut the system down. Your utility will need to install a meter that keeps track of what you take from them and what you sell back to the utility.
Now in the event of a power cut, the combiner shuts the system down, as they don't want downed lines going live from your system. This is why standby generators must have an automatic transfer switch to disconnect you from your utility in the event of a power cut.
Now make sure you have a really good ground. If it does not meet spec. then you will need a new one. I really went over the top with mine, when I built the house, so it was fine.
Now one important point. The grounding of the system, and especially the panels, must be well done. A big problem has been dissimilar metals causing galvanic corrosion resulting in high resistance grounds and fires over time. So watch out for that.
I did have issue getting the installation really tidy, like specifying pull elbows rather then ugly bent steel. This actually speeded things up, as it makes pulling wires quicker and easier Failure to adhere to this spec of mine, was the cause of one of the stops I called. If you have a good outfit, then they will in the end be happy, One of the senior engineers wrote my a nice eMail to say they are using my photographs in their teachings and instructions now.
I am glad to say we passed both electrical and building inspections first time. The Inspection from Dakota Electric was the most rigorous of all, which is as it should be. A the end they placed their sticker and turned the system on, and it has stayed on since with no issues.
I have no had any buzzes due to this system on my audio systems, except for those Marantz were responsible for.
Now, I am hoping that this system will replace 70% to 75% of our electrical usage. The big user is AC. Our unit while running used 7.5 KW, which is max panel production in a good noonday sun.
Last month we had a bill of $125 as we have had a really humid heat wave. I have been in credit two months and had minimal bills the other months. Last month's bill would have been over $500 without the solar panels. The panels have produced 8.1 megawatt hours of electricity so far this year. I am hoping for around 12 megawatt hours by years end. Last year we consumed 16 megawatt hours. I reckon we should make another 4 megawatt hours.
Their program helps you keep track on your phone, and you can check that all panels are producing, and you would see if a panel had failed right away.
So, that is what I know right now. Unfortunately you have to be careful as inappropriate installations and unrealistic goals abound.
