On Sunday, 40,000 runners will expend a lot — A LOT — of energy running all 26 miles of the Paris marathon. But for a smidge of an instant — 82 feet, or approximately 0.06 percent of the course — not all of that energy will go to waste. The runners will stomp down on energy-harvesting tiles that can repurpose some of their effort to help power screens and signs.

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They might even collect enough energy to run a lightbulb for five days.

So, that’s not a lot of energy. But the idea is still cool. Imagine if more of the roads on the course were already outfitted with this technology and were constantly collecting energy from people running over them. When a pack of marathoners came through, you’d be able to power many, many lightbulbs. Or a house. Or the after-party.

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