Living Sustainably
in the shadow of climate change

February 2015
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climate change and solar power
Filed under: General, Solar Power
Posted by: Guy @ 12:09 pm

I have been keeping meticulous records since I installed our solar array in 2009, and have been keeping all this information in a spreadsheet.  One of the things I have been doing is comparing the estimated power I should expect with the actual power generated.  The National Renewable Energy Lamps tool called PVWatts allows you to input the specifics of your solar array including its location, number of panels, and orientation etc. so that it can give you an estimate of how much power you should expect.  At the end of every utility billing cycle, I access the records from the web interface for the solar inverters on my system to determine exactly how much power was produced by the array for each month.  The chart below shows the calculated estimate vs. actual production.  Notice that the estimated production bumps up each year as I have added panels to the array.  The scale on the left represents kilowatt hours per month.

click the chart to see more statistics about my solar energy production

As you can see the deviations from anticipated production are increasing over time.  Sometimes my array produces a lot more when there are extended sunny periods and sometimes a lot less when we have long periods of overcast and stormy weather.  It is difficult to say whether this trend is going to continue to be more extreme and whether or not this is due to climate change.  It certainly is interesting.

One Response to “climate change and solar power”

  1. rj Says:
    It almost looks like you experienced an anomaly by producing more than calculated in 2012, while 2013 has reverted to pretty close tracking.