It’s called Wearable Technology and believe it or not that little black dress your girlfriend just bought could generate enough solar power to charge an iPhone. Sound like something in the future? Not really.

Earlier this month Dutch fashion designer Pauline van Dongen unveiled  prototypes of a black “solar” dress and a solar coat that collect and store enough energy to charge a smartphone. Her company, Wearable Solar, fashioned a thin foil of 72 flexible solar cells inside a leather panel on the dress. For the coat they used 48 crystalline cells and placed them behind leather openings or ‘windows.’ Women wearing either garment need only be out in the sun for an hour to gather enough energy to charge their smartphones by 50%.

“Wearable technology is literally what it says,” says van Dongen. “All the things that we (will) carry around, like smart watches and Google Glass, they all need continuous power. Wearable Solar aims to give a sustainable solution to these problems that we’ll be facing more and more.”

Still Wearable Solar has an immediate hurdle to jump, just how to make that little black dress washable.