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.
Why size matters
When solar panels first went on the market, generating a significant amount of power would've required far too many of them to fit on the roof of a typical home.
But since today's panels are ten times more efficient, ten times fewer panels of the same size are needed to generate the same amount of power. That's why it's become possible for typical homeowners and small businesses to generate all the power they need with a simple rooftop system.
Manufacturing costs
Of course, needing fewer panels wouldn't make generating solar power cheaper if they wound up costing a lot more.
For example, though commercially available solar panels are generally around 20% efficient, scientists have created a panel that's almost 40% efficient. Instead of having just one layer, it's composed of three different layers, allowing it to capture energy from a broader spectrum of sunlight.
But, though these multi-layered panels can generate the same amount of energy as commercially available single-layer ones using only half the space, they're extraordinarily expensive to make. Since it's unlikely that's going to change anytime soon, these super-efficient multi-layer panels just aren't economically viable.
Fortunately, the opposite has been true for the basic single-layer solar panels used in rooftop projects today. Increased efficiency has been accompanied by steadily decreasing costs.
The result has been great for both individuals and the environment, as more and more people discover they can substantially reduce their energy costs with a simple rooftop solar system.