# The tutor continues from his last post about the value of solar energy dollars.

In my last post I discussed the Wattage one might expect from solar energy for \$100. Based on a graph from Scientific American, the equation for Watts per \$100, W, at time t (with 1980 as year 0 and 2008 as year 28) turns out to be

W=4.2e^(0.0787t)

Extrapolating, one can plug in 35 for t to get the predicted Watts per \$100 today:

W=4.2e^(0.0787(35))=66Watts for \$100

In fact, just talking about the hardware itself, one can get more than 100W for \$100 in 2015 (see sunelec.com, for example.) However, for a typical residential application the price per Watt might be more like \$4.50, installed. Thus, the Watts available for use might be more like 22 per \$100.

Interestingly, taking the average of the “theoretical” 100W for \$100, along with the “practical” 22W per \$100, one arrives at 61W per \$100, which is fairly close to the 66W predicted by the graph.

I’ll be talking more about solar energy for households in coming posts:)

Source not already mentioned:

pv-magazine.com

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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