The electricity that powers San Francisco's streetlights, schools, and international airport begins as a torrent of water inside—of all places—the supposed natural sanctuary that is Yosemite National Park. A century ago, a pristine valley was sacrificed so that San Francisco could continue to exist.

The Hetch Hetchy Power System is still responsible for San Francisco's municipal power, keeping the lights on in public buildings and the gears turning for the MUNI transportation system. This vast piece of infrastructure comprises a dam, three powerhouses, the company town of Moccasin (which is entirely owned by San Francisco), several substations, and hundreds of miles of power lines connecting the city to its lifeblood. A parallel system of water pipes carries water from Yosemite into San Francisco.

Last summer, San Francisco-based artist Jenny Odell set out to see this system hiding in plain sight. Her project Power Trip documents a reverse journey, following the path of electricity backward from the city to Yosemite. She painstakingly traced the power lines using Google Maps's satellite view, mapping out the path that she later took by car.

(We've featured her work on satellite image cutouts on Gizmodo, too.)

The route took her past suburbs, vineyards, large expanses of grass, parking lots, and, finally, onto remote backroads as she got closer to the origin point. Huge manmade structures rose in stark contrast out of nature.


"To a person completely unacquainted with contemporary civilization," she writes ,"it would seem obvious that the towers and pipes (the Kirkwood penstock's vertical drop being totally baffling to the eye, describable only as sublime) are monuments." Yet her very presence aroused suspicion—both in the suburbs of Fremont and in the remote powerhouses near Yosemite, where ranger vehicles tailed her car.

The penstock at the Kirkwood powerhouse, where water flows down to power turbines.


One of the strangest sights was Moccasin, the company town less than twenty miles from the western edge of Yosemite. "It felt very not welcoming," she said to me, "I got the distinct impression I wasn't supposed to be there."

Owned by the City and County of San Francisco, Moccasin was created to house staff who maintain the powerhouse nearby. Every house is identical, with the same roof of red tile.

Above: Moccasin Powerhouse, below: the houses in Mocassin

For Odell, the experience illuminated how easy it was for massive infrastructure to hide—and how suspicious it might seem when someone went looking, even for entirely innocuous reasons.

But to understand how our lives relate to larger movements of resources and energy around world—to be environmentally conscious, really—requires looking at infrastructure.

"Infrastructure is the point at which something that's so big it's hard to understand finally comes down to your scale and you can see it," she says. A light switch in San Francisco is where everyday life intersects with the vast national power grid.

Top: Old Mission Park in Fremont, middle: farms near Modesto, bottom: Warnerville substation


I first became aware of Hetch Hetchy last summer, when wildfires in Central California began worrying people in San Francisco. The same reservoir behind the dam that powers the city also supplies it with water, and ashes from the fire could contaminate the drinking supply. "It's impossible to separate water from power," says Odell, who is working on another project related to water.

Lack of water was a constant problem in the early days of San Francisco. After the devastating fires of the 1906 earthquake, the city looked high and low for a reliable source of water. As luck would have it, the ideal location happened to be in the middle of Yosemite, a National Park created to preserve nature less than two decades earlier. Over the protests of environmentalists like John Muir, a dam was built and a valley flooded. You might think this as a sacrificial landscape, a valley destroyed so that San Francisco could thrive. Even a National Park is not spared.

In recent years, there's been a push to dismantle the dam and restore the valley. There are other potential sources of water for San Francisco, but the environmental argument against restoration is about power. Hetch Hetchy's 1.7 billion kilowatt hours of hydroelectric power every year are a relatively clean source of power. The damage is already done, the sacrifice made. Instead of averting our eyes, we should look at it.

The dam in Yosemite

A montage of photos tracing the trip from San Francisco to Yosemite.

All images courtesy of Jenny Odell