When Portugal’s electrical system needs a boost, a signal activates a power plant buried deep in a hillside in the country’s scrubby, pine-covered north. Inside the man-made cavern, valves, nine feet in diameter, suddenly open, allowing water draining from a reservoir four miles away to begin streaming through four massive turbines. Over 15 years in the making, this vast hydroelectric power plant by Spanish energy giant Iberdrola could hold some of the answers to the planet’s energy woes.

Visiting this site in 2022 for the New York Times was impressive, from the mammoth scale of the plant down to its most intricate details; the mosaic of wires, nuts and bolts carefully assembled in a true feat of modern engineering. Rudimentary-looking and sci-fi all at once, this space felt world’s away from the organic environments I’m used to photographing.

Offering me a backstage glimpse into what’s essential yet seldom seen or thought about, this story allowed me to contemplate humanity through a different lens and to reconnect to my background as a scientist.

Commissioned by Renee Melides for The New York Times. Words by Stanley Reed.