Suppose your local gas station offered to let you prepay for 10,000 gallons of gasoline today at a lower price than what they're currently charging.
That would mean locking in a low price for all the gas you'll be using over the next 25 years, assuming you drive 12,000 miles a year at 30 miles per gallon.
Since gas is only going to get more expensive over time, it would also mean saving a boatload of money.
Locking in a low electric rate
Well, that's essentially the deal you get when you invest in a solar energy system.
Once it's up and running, your solar panels will be generating free electricity for the duration of their 25-to-30-year expected lifetime.
And, when you see solar panels going up on someone's roof, you can bet that it's because the installation costs worked out to be substantially less than the amount they'd be paying for electricity over the next 25 years even at today's rate.
So, as utility companies inevitably raise their rates, those solar panels are going to provide even more savings over their minimum expected 25-year life.
Of course, the longer your panels last, the more free electricity they'll be generating and, hence, the more money you'll be saving.
Which brings us to the good news.
Surpassing expectations
Researchers at Sandia Labs have just concluded a five-year comprehensive study on solar panel degradation. They examined 834 fielded solar panels from seven manufacturers representing 55% of the U.S. market in three different climates.
The result?
Sandia's research team found that most solar panels not only meet their maximum expected lifetime of 30 years. They exceed it.
Of the 23 solar systems that were examined, 13 turned out to have lifetimes that exceeded 30 years.
All of the models studied were manufactured after 2015. But, as the researchers note, their degradation rates were about the same as those found for older models.
That's good news on two more fronts.
No sacrifice in quality
First, it means that even solar panels installed before 2015 are likely to last longer than 30 years.
But, as the researchers also note, solar panel prices have dropped a jaw-dropping 85% over the last decade. The reasons include:
Economies of scale
Use of new, higher efficiency cell designs
Automation of production lines
Larger panel size
Changes in materials, e.g., thinner glass and frames.
But the fact that most panels constructed today are still going to exceed their 30-year expected lifetime means that making solar power vastly more affordable didn't involve any sacrifice in quality.