Let me give you a little information on utility scale solar where those big beautiful solar farms glisten for a hundred miles in every direction. The cost for these farms are hovering between $1.35 and $1.65 per watt for a basic turnkey installation. The reason that these farms are so much cheaper than roof-mount solar for homeowners is that the installation has become almost robotic. The panels along with their wiring are put on panelized skids which are done in a factory. And in the last few years it is the advancements in the modular racking system and electrical wiring harness that has seen the most improvements which means that they now cost much less. Standardized and streamlined installations are making utility scale solar become commercially attractive. Still you are not going to see prices like this until you get into installations of 5 to 10MW…..and remember that a MW is one million watts.
So are you, the homeowner, going to get the benefit of such a large purchase and put solar on your roof for $1.35 per watt? The answer is a resounding “No!” but at least you are aware of the low end of the scale. For the homeowner the price of solar is significantly more due to the individualized service you receive. Just think about it, you receive an individual assessment of the physical condition of your roof, an individual assessment of the sunlight that your roof receives, as well as, an individual choice of a number of sizes, outputs, and finishes. For our purposes we are going to keep the total cost of installation including the solar panel in the range of $6.00 per watt. Let’s begin by asking a few questions:
- Look at your electric bill and find out how many kilowatt hours of electricity you are using each month.
- Do you live in the Southern United States where you receive the greatest amount of direct sunlight? If not, you will need to expand the size of your solar array accordingly.
- Are you able to install the panels on a south facing roof where you will receive the greatest amount of direct sunlight each day?
The generating capacity of a typical solar panel is 10 watts/sq. ft. So for every kW you generate, you need about 100 sq. ft. of solar panels. Now we can begin to answer the question of how much it costs to go solar with the following example:
You live in a 1000 square foot home somewhere in the Southern United States. Your average energy usage is 500kwh each month or $100 per month. Assuming that the turnkey cost of installing a roof-mount system is $4.00 per watt (and you are providing your own labor), then a
5 kW system will cost $20,000, and the payback period would be 17 years without subsidies. However, when you subtract the current subsidies that are available the total cost will be reduced by one-third to one-half which makes the PV installation much more attractive. Then the payback period is 8.5 to 11 years.
See You Next Time! Dr. Stripling