A view from the water of the Exploratorium at Pier 15.

When the Exploratorium, San Francisco’s celebrated science museum, opens in its new location on a pair of renovated piers April 17, the knowledge seekers and tinkerers of the world will be reunited with beloved displays like the gravity-powered calculator and the tornado machine. Visitors will also discover new exhibits, such as a pedestrian bridge that is constantly enveloped in fog and a ceiling aperture that transforms the site’s new glassed-in observatory gallery into an architectural sundial. But perhaps the museum’s biggest experiment will be the building itself.

Designed by EHDD, the Exploratorium’s new 330,000-square-foot indoor-outdoor campus is targeting net zero energy. If the effort succeeds, the institution will be the largest net-zero museum in the United States. Such an ambitious goal would have proved a serious challenge in the Exploratorium’s old quarters in the careworn Palace of Fine Arts, where the museum first opened its doors in 1969. The renovation of the historic 1915 structure on Pier 15 (Pier 17 is reserved for future expansion) not only brings net zero within reach, but it also allows the Exploratorium to turn the quest for energy self-sufficiency into a kind of meta-exhibit.

Treating the long, narrow pier as a raw canvas for the museum, EHDD retained the existing building’s steel superstructure and its concrete cladding. On the street side the architects did a lot of seismic work in the historic bulkhead and redid the stucco at the entrance. But they gave the rest of the concrete exterior a careful makeunder, stripping away flaking paint from the transit shed—now the north tip of the museum—and leaving behind the ghosted images of old signs. “Our strategy was not to paint it over and make it look new,” EHDD principal Marc L’Italien said during a recent tour, “but to show the passage of time to the degree we could.”

From its perch over San Francisco Bay, the building harnesses the relatively consistent temperature of the ocean for heating and cooling. Two titanium heat exchangers regulate the temperature of fresh water piped through radiant floor slabs in the main exhibit hall, the second-floor offices, and the new observatory and restaurant at the end of the pier. Plus, the structure’s ample 900-foot span meant the architects could specify the largest building-mounted solar array in San Francisco. “We’ve got the great advantage of a building that has a vast amount of roof area, given the amount of floor area,” said L’Italien. “It’s the opposite of a high-rise.” An exhibit at the entrance will interpret data from the solar panels in real time; at the other end, a large window looks onto the cooling room for the bay-water exchangers.

With nearly three times the space of the old location, the new site allows the Exploratorium to open itself to the outdoors for the first time. The aprons of the pier will feature interactive exhibits that explore the science of the bay, from an Aeolian harp that sings in the wind to a rain chamber that lets visitors dial up previous storms. “In the past we might do an exhibit about optics on a tabletop,” said Tom Rockwell, the museum’s director of exhibits. “But now we can do optics with the real sun passing through the real mist and actually engage the whole environment.”

Net zero is a particularly ambitious goal for a museum with hundreds of electrically powered exhibits. But setting up the museum staff—an inherently techie group—with what is essentially a giant net-zero-capable machine can only help its chances. “They interpret everything,” said L’Italien, recalling a debate among the staff over the merits of automated versus manual windows. “If there were a client that would use a manual window, it’s these guys. They’d get in there and make a show out of it.” He adds, “With net-zero buildings, you don’t just turn on the switch and they work—you have to monitor and work with them. You couldn’t end up with a better group of people to be doing that.”