20 years ago, transitioning to clean and renewable solar energy would've probably meant taking a financial hit. Fast forward to today, and solar panels are likely to be a big money-saver.
One reason the balance sheet has flipped is that solar panels have become much more efficient.
But what exactly is "solar panel efficiency" and why does it matter?
How it's defined
Solar panel efficiency is a concept from physics. But don't let that scare you since it's actually pretty easy to understand.
When sunlight strikes a solar panel, there's a certain amount of energy contained in it. But the panel will only convert some of it into electricity. The efficiency rating of a solar panel is simply a measure of how much of the available energy in sunlight gets converted.
Today's rooftop solar panels, for example, generally have an efficiency rating of somewhere around 20%. So, that just means that, when sunlight hits them, today's models typically will convert around 20% of the total amount of available energy into electricity.
More efficiency equals fewer panels
The practical upshot of solar panel efficiency is even easier to grasp. The more efficient your solar panels are, the fewer you'll need to generate the same amount of energy.
The first commercially available solar cells, for example, were only 2% efficient. That means that you'd only need one-tenth the number of today's 20% efficient panels of the same size to generate the same amount of power.