Source: CNN

On the roof of the O2 Arena, one of London’s largest indoor venues, there’s a small cluster of very peculiar wind turbines.

They look nothing like the tall, imposing ones that are increasingly deployed both inland and offshore around the world — at less than six feet (1.8 meters) in height, they’re a fraction of their size, and produce much less energy.

But being small gives them a strategic advantage: they can be deployed almost anywhere, and were designed to be retrofitted onto existing streetlights, where they can be powered not just by the wind, but also by the artificial breeze created by passing vehicles.

“If you stand next to the road and a bus comes past, you feel that airflow,” says Barry Thompson, CEO of Alpha 311, the company that designed the turbines. “Why is nobody harnessing the energy that cars are generating when they drive past?”

Now, after the successful trial at the O2, Alpha 311 is preparing to launch a refined version of the turbine that will be suitable for commercial installations.

Read more: This small turbine can harness the power of passing cars