Latest articles by The Solar Nerd

When it comes to buying solar panels for your home, the first thing that manufacturers usually tout is the panel’s efficiency. Solar panel efficiency refers to the amount of sunlight hitting the panel that gets converted into electricity. The intensity of sunlight can be expressed in watts - the same unit used to measure electrical power. For example, if 1,000 watts of sunlight is shining on your solar panel and it generate 200 watts of electricity, the panel is 20% efficient.

Do you already have solar panels on your home? Normally that’s a great thing, but maybe you’re looking at your monthly utility bill and wondering why it’s not lower. For most people, helping the environment is one reason why people go solar, but the top reason according to market research is saving money on your electric bill. This is why it can be so frustrating if you’ve spent thousands of dollars on a solar installation or committed to a 25 year solar lease and you’re looking at a monthly electric bill that’s still pretty high.

If you live in a city where home solar is popular, like any of the big cities in southern California or the Bay Area, you’ve probably heard about Sunrun. Maybe you’ve seen their blue vans rolling around town, or had their sales people knock on your door. Sunrun is the largest home solar installer in the US by a wide margin: they currently have about 14% of the US market. Not only that, but they recently acquired Vivint Solar, adding another 6% market share to their total.

According to Berkeley Lab, a large majority of homeowners are now choosing premium equipment for their home solar systems, including high efficiency solar panels and microinverters. When it comes to panels, one of the brands that’s producing some of the highest efficiency solar panels is REC Group. Founded in Norway in 1996, the company went through the kind of financial difficulties that many solar manufacturers have experienced, culuminating in their acquisition by the Chinese company BlueStar in 2014.

Solar panels don’t have any moving parts and they last a really long time - but they don’t last forever. There are a lot of reasons why solar panels go bad, from physical failures such as the layers in the panel separating to chemistry-related phenomenon such as potential-induced degradation. It may take decades for the drop is power to be significant, but over time all solar panels lose efficiency. (A solar panel’s 25 year power warranty reflects the manufacturer’s confidence in its long-term performance.

Tesla Energy, the division of Tesla responsible for solar and home battery products, makes the well-known Solar Roof that looks like sleek roofing tiles but generates clean electricity. But the Solar Roof is an expensive product that is best installed on a home that needs a new roof. If you have a newer roof that doesn’t need replacement, it typically doesn’t make financial sense to install a Solar Roof. In fact, Tesla recently dramatically raised the cost of the Solar Roof - double the price, according to some.

Petersen-Dean, a roofing and solar company founded in 1984 that operated in nine states, went bankrupt in 2020, leaving many of its customers in limbo. The company operated in Arizona, California, Colorado, Florida, Hawaii, Louisiana, Nevada, Oklahoma and Texas. They started as a roofing company, then began offering solar installations, especially in California where solar installations are required on some new homes. While the COVID pandemic was perhaps the straw to break its back, the company was apparently in poor financial health for some time.

If you’ve ever seen a solar panel up close, you might have noticed thin little wires running across each cell. Those little wires do the important job of carrying electrons (electricity) generated by the solar cells into thicker main wires of the panel. You might know from high school science that thin wires have higher resistance, which means they lose more electricity as heat. In a solar panel, that means lower efficiency.

For most people, their home is their biggest financial asset. Drilling holes into it might seem like a bad idea, but that’s usually what’s needed to install solar panels on a roof. And yet, this does not need to be cause for concern: there are millions of homes with solar panels around the United States, and the majority of them are problem-free. Solar panels do not need to cause roof leaks: they can last problem-free for 25 years or more.

I live in Buffalo, a city known for chicken wings and wicked snowstorms. Despite my city’s reputation for snow, much of the year is great for solar production. Still, I can expect to lose at least a couple weeks of energy production in the middle of each winter due to snow collecting on my panels and blocking out sunlight. It doesn’t take much snow to curtail electricity production. If there’s just a light dusting, there might be enough residual heat energy in the glass to melt the snow.