Nosferatechnology

"We're very excited about the new photovoltaics," said Dr. Stoukre. "The latest materials to come out of the lab have some amazing properties, particularly with regard to light sensitivity. They practically scream energy when you expose them to sunlight."

"Not any other light, though," Newson put in. "Just sunlight."

"Oh?" Dr. Brenner blinked. "That's unusual."

"We suspect it's something to do with the... origin. We've had to stake three of them trying to work out the kinks."

"Luckily," said Newson, "there's always more idiotic grad students willing to sign the waiver. Three days later, we're restocked. Thank goodness for 'Twilight.'"