If you live in Portland, your lights may now be partly powered by your drinking water. An ingenious new system captures energy as water flows through the city's pipes, creating hydropower without the negative environmental effects of something like a dam. Small turbines in the pipes spin in the flowing water, and send that energy into a generator. "It's pretty rare to find a new source of energy where there's no environmental impact," says Gregg Semler, CEO of Lucid Energy, the Portland-based startup that designed the new system. "But this is inside a pipe, so no fish or endangered species are impacted. That's what's exciting."