Spanish energy firm Endesa is responsible for the installation, which costs more than traditional lighting up front, but offers equal value over the lights' lifespan.
And, of course, the best value of all: Barcelona expects its municipal power bill to decline by a third thanks to those timers.
Here's a look in a video from GOOD magazine:
Street lighting accounts for quite a bit of a city's energy bill, so finding ways to reduce even a little bit of cost can make a big difference.
The question that remains: how valuable is a lit, but empty street when it comes to cracking down on crime?