Residential solar system cost

I ran across an interesting brochure from greensolarpr.com on how to tell whether solar is right for you. It includes how to calculate size and gives some average costs. The assumption is that it will be tied into PREPA. If not tied to PREPA, there may be some hardware savings offset by the need to have batteries.

I thought this was the key paragraph:


Residential Grid
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Tie systems can start as low as $2000 (installed) for a starter system, all the way to $50,000 or more.

Average Component Cost:
$5 per watt. This includes all the components including panels, inverters, mountings and electrical accessories.
 
Add $2 per watt for battery backup systems.
 
Average Installation Cost:
 
$2 per watt. This usually includes the physical installation of the system and connection to the grid.
 
Example:
 
For  the  example  above  4.52 kW Grid  Tie system cost  is  near  $22,600  and  $9,041  for installation  cost  including  design  and  permitting  for  a  total  of  $31,645.    Adding  a  battery backup system for emergency power can add additional $9,041 to your system for a total of $40.687.
 
Your system total price can vary as little as 10% more and as 20% less depending on various factors such as design, PV shadow, type of PV and price negotiations.  Therefore your system estimated range is 25,316 to $34,810 for Grid Tie PV Direct and $32,549 to $44,755 for a Grid Tie with battery backup.

[Emphasis added]

http://greensolarpr.com/pdf/How to Calculate your Solar PV System.pdf 


This is a system for a home using 600KWH/month. If we assume 25cents/kwh, the annual cost of purchased (PREPA) power in this example is $150 per month or $1,800/yr.

If we use the lowest number in the installation range (because everything always comes it at low range, right?) we can call it $25,000

We will assume that once the system is installed, all electricity in the household will be free. There will be some maintenance costs over the life of the system but they are probably going to be minor. As long as we don't get another Maria, or Georges, or Hugo etc. so let's set them aside. 

Simple payback method divides the total cash outflow by total cash inflow:

25,000/1,800 gives us a payback of just under 14 years. If it is the high end of the range, it is $45,000/1800 or 25 years.

The calculator does mention rebates and, though not mentioned, there may be tax deductions or credits. This will bring the cost of the system, to the homeowner, down and maybe make it attractive. Unfortunately, it doesn't really bring the cost down. It merely shifts the cost from the homeowner to other homeowners/taxpayers, to PREPA, to other PREPA customers and to others. 

Doesn't seem right for neighbors to be taking from their neighbors.

Don't get me wrong, I have been interested in traditional and alternative energy  since the 60's. I studied nuclear power in the 60's, learned about OTEC in Dr Werner's oceanography classes in 1973 at IAU. In 1975 I sold solar water heaters in Puerto Rico.

If solar electric made economic sense, or perhaps I should say when solar makes economic sense, there will be no bigger fanboy than me. We are getting closer and closer to that point but we still have a ways to go.  

Battery technology is needed to make it feasible and there are some amazing things going on with large scale batteries. We are not there yet, either.