Do you have to clean solar panels?

Years ago, shortly after putting solar panels on my house, I ran some tests to see if cleaning my panels of pollen made a difference. At the time, I found minimal difference in the output of my entire system so I concluded that I didn’t really have to worry about keeping the panels clean. Plus, most of the on-line info I found supported this, stating that rain naturally washes away most of the debris that settles on the panels.

However, this past year, I upgraded my system with solar optimizers. Due to tree growth, my array was having more problems from shading, causing the entire system performance to degrade. Optimizers allow each panel to operate more independently, reducing the negative effect of shading on one panel. In addition, the optimizers were connected to the internet, allowing me to monitor the output of each individual panel. Most modern systems provide this capability. It’s an extremely powerful troubleshooting tool.

As an energy geek, I wanted to see how my panels were performing after installing the optimizers, since I paid a good chunk of change for the upgrade. Sadly, when I compared my system output to past years, I didn’t really see much, if any improvement! Why would this be?

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Is solar efficient enough?

I recently overheard a conversation that made me think. A man, who was clearly respected by his friends as someone knowledgeable, commented that solar wasn’t ready for prime time because it isn’t efficient enough. But is this true?

The simple answer is “no.” Solar is plenty efficient. The solar electric panels that go on your roof are 15%-20% efficient. Solar hot water systems are about three times more efficient since they heat water directly. So the most intelligent system consists of a couple of solar hot water panels and a roof full of photovoltaic (electric) panels.

But still, you might be waiting for systems to get much more efficient. After all, semiconductors get faster and cheaper every year. If you did this, you’d be making  a mistake.

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