Solar energy’s greatest nemesis is a cloudy day. It’s second-greatest is dirt. Smudge up a solar panel and you won’t soak up all that power-generating sunshine. Unfortunately, cleaning panels can get expensive fast.

“If you own a solar farm — so, you’ve got, say, something like anywhere between 20 to 50,000 solar panels. That’s a huge expense,” said University of Houston nanotechnologist Shay Curran. “That’s somewhere in the region of $100,000 to $250,000 every time you need to keep them clean.”

But what if solar panels could clean themselves?

Curran has developed a coating that repels water that would otherwise stick to panels. Water droplets slide off the surface, collecting dirt along the way. This saves money on cleaning, reducing the cost of solar energy.

“The thing about any kind of technical advance means you get to a certain point, but then you realize, we could do some other things,” said Curran. “We could make it better.”

Jeremy Deaton writes for Nexus Media, a syndicated newswire covering climate, energy, politics, art and culture. You can follow him at @deaton_jeremy.