The short answer is 14 – 20%. That means that nearly 20% of the sun’s energy that hits the panels is converted to electricity to enter your home or business.
Let’s put solar power efficiency into context compared to another typical energy user that most of us use every day. A gasoline vehicle is 14 – 26% efficient according to the U.S. Department of Energy. That means that only 14 – 26% of the fuel that you put into your tank moves your car down the road. Of course, when your tank is low you need to go back and fill it up again. Solar panels produce clean energy every time the sun hits them over their more than 25-year lifespan!
In historical context, solar power efficiency has dramatically increased. Bell Labs produced a silicon solar cell capable of 6% energy conversion with direct sunlight.
We’ve come a long way – from the relatively inefficient, extremely expensive solar panels on NASA’s satellites in the 1960’s, to our current solar panels that make energy independence a reality for many of us in the St. Louis and surrounding region.