Chapter 6:

The Problem:

In Central Oregon it is generally thought that we are in a nearly ideal place to install PV panels to generate electricity from sunshine. For the purposes of this problem we will assume that the sun is providing 200 W/m² around the clock throughout the year (this is what average means). We will also assume that electric power is valued at $0.12 for each kWh.

I hunted around on the web a little and found a "300W" panel (Conergy PE 290P series) which is 15% efficient and costs $270 per panel at this point. The effective area of the panel is 1.75 m².

Ignoring, for the moment, the cost of installation and other electrical equipment needed to make this useful what is the payback time for just the cost of the panel under these circumstances in Central Oregon? You will need to figure out how much energy this panel can produce in a year and what that power is worth.

Then let's get a little more realistic. What is the payback time if the cost of shipping, installation, and other equipment you need to sell the power back to the utility doubles the cost of your system? You shouldn't need to do any new calculations to get this. What is the price of a solar panel at which the pay back time for the whole system is 5 years?