Preparing the Solar Project

What Equipment

Our roof had limited roof space facing south, and a very low pitch angle.

A south (or at least east/west) facing roof is best.  North facing isn't going to generate electricity.   While we aren't facing directly South, we are about 190 degrees, which isn't bad, and had no shade to interfere.   

Ideal pitch angle is available if you look on the web at places such as this.  That is all well and good, but the reality is that if you are placing panels on the roof, you aren't going to change the pitch angle.  It isn't worth it due to the danger of wind knocking them off (or vibrating the solar panels), and the cost of structure to achieve the tilt.  So I was stuck with about 15 degrees. 

I carefully measured (from the ground) the roof space, and soon realized it wasn't enough to generate 10KW, and I wanted 10KW to make the venture worthwhile.  That problem was resolved by:

1. Using Silfab's monocrystalline high efficiency panels. The panels we went with generate 285W each (versus the typical 250W) meaning the same power could be generated with 5 fewer panels.  
2. Placing Schletter windsafe racking at about a 30 degree angle on the north side, so it also faced south.

Those two items brought us to a full 10KW of power on the roof.

In addition to the solar panels you need to have an inverter that converts the DC electricity generated by the panels into AC usable by the utility.

There are two choices in that regard:

1. String Inverters (one inverter does numerous panels)
2. Micro Inverter (each panel has its own separate micro inverter)

There are arguments all over the net as to which is better, but ultimately we went with SolarEdge string inverter with optimisers.

Micro inverters have an advantage in that they are generally warrantied longer, and deal with shading issues.  SolarEdge string inverter was less costly, and the optimizers also dealt with shading issues.  While the warranty was shorter, the inverter was at the ground so easily replaceable.

Microinverters are sitting under hot panels, generating their own heat as well (which isn't good for the panel or the inverter) and while warrantied there have been failures and it is the labour to replace them that is costly.  I'm not planning to climb up on the roof.  

Both solutions, as I mentioned, dealt with shade issues.  Without optimization you generate based on the weakest link (ie. most shaded panel) in the solar panel chain.  Why am I concerned about shade on an unshaded roof?  Snow!  

What Company?

It was a bit of a struggle to find a reputable company for the solar install.  I had already priced out the components.  What I hadn't priced out was the cost of:

1) Building permit (not normally required, but I had the raised racking that changed the roofline)

2) Three days to do the install (as I mentioned, I didn't have an ideal metal roof)

3) Electrician to do hook-up

4) ESA Inspection

5) Miscellaneous project management.

I eventually found Efan Solar.  They had been around a while, and seemed comfortable in dealing with the roof I had.  I wanted experience; I didn't want issues.   There pricing was also the lowest of the prices I received, but they were able to work with the suppliers I had specified.

...... to be continued