Organizers of an elaborate midwinter light display running until January along the Meguro River in downtown Tokyo, a popular cherry blossom viewing spot in spring, are going off the grid as a way to limit harm to the environment.

Biodiesel fuel made from used cooking oil collected from residents and restaurants in the neighborhood is being used to power more than 420,000 LED lights along the river. In a nod to the blossoms that appear in late March, the lights are a pale pink.

The novel approach — organizers say it's the first of its kind in Tokyo — stems from concerns about energy conservation that emerged when the Fukushima disaster began unfolding more than five years ago. While LEDs are more efficient and last longer than conventional bulbs, they're also being used in many more places, meaning they risk taxing electricity supplies regardless of how well they use energy.