Just under a decade ago, I reviewed a Las Vegas development called CityCenter for ARCHITECT. After listing some of the center’s green features, like low-flow showerheads, which had helped it earn a LEED Gold rating, I wrote: “Yet it’s hard to imagine anything less green than 18 million square feet of air-conditioned space in the Mojave Desert. Admirable as some features of the complex may be, the only truly sustainable decision would have been not to build it.”
I didn’t know it at the time, but 40 percent of the greenhouse gases emitted into the atmosphere can be traced to buildings—more than to any other source. And a sizable portion of that 40 percent is the sunk cost known as embodied energy: the energy used for construction (including the mining, manufacturing, and transportation of building materials).
As an architecture writer, I have been disheartened by the lack of attention the profession has paid to this reality. It’s as if architects believe that embodied energy, which is, of course, invisible, can be wished away (or at least offset with minimal effort). This idea is reinforced by designers who declare their buildings green while either ignoring embodied energy or claiming that operational efficiencies somehow make it irrelevant—a kind of fairy tale some of us are all too happy to believe. I’m equally disheartened that architecture critics have, for the most part, failed to expose this myth in their reporting.
It’s something I tried to do in an article about the Stavros Niarchos Foundation Cultural Center in Athens, the new home for the Greek National Opera and the National Library of Greece. Looking to create, essentially, a new Acropolis, Renzo Piano Building Workshop embedded the two buildings in a vast artificial hill, 100 feet high at its peak. This involved building concrete retaining walls and placing some 654,000 cubic feet of earth between those walls. To protect against seismic activity, workers filled steel tubes with rocks, then hammered the tubes into the earth at 10-foot intervals—creating 3,500 “gravel piles.” The amount of energy expended was astronomical.
Yet because the center, completed in 2016, has various green features, including rooftop solar panels (which will meet a portion of its ongoing energy needs), it earned a LEED Platinum rating from the US. Green Building Council. LEED’s checklist system doesn’t consider embodied energy, which is like an ocean rating system that doesn’t mention water. But in a book about the project, a prominent journalist called the center “a triumph of environmental sensitivity,” helping to cement its reputation as a good thing for the planet. (My efforts to learn more about the building’s embodied energy have been unsuccessful—neither Piano’s team nor the building manager could provide relevant data.)
Even more troublesome is Apple Park, the vast donut-shaped corporate headquarters in Cupertino, Calif., conceived by Steve Jobs, designed by Foster + Partners, and completed in early 2018. The energy expenditures associated with the project are mind-numbing, starting with Apple’s decision to tear down 24 serviceable buildings on the property and build the new HQ from scratch. The design required 900 curved glass panels, each 10.5 feet high and up to 46 feet wide. The panels were shipped from a factory in Germany to a container port in crates the size of mobile homes. Loaded onto ships, they were transported across the Atlantic Ocean, through the Panama Canal, and up the Pacific Coast. Once in port, the three-ton panels were transferred to trucks and driven to Cupertino, where they were lifted into place. That's a lot of embodied energy.
Yet Apple continues to call its headquarters “the greenest building on the planet.” Which suggests either that the embodied energy isn’t a concern, or that the solar panels on the roof offset it. My repeated requests to Apple (some through its chief environmental officer, Lisa Jackson, a former EPA administrator) for information about the building's energy balance sheet have gone nowhere. Yet my first question—how much energy are the solar panels producing—should take a few seconds to answer. The next question—how much energy went into the creation of the building?—would require calculations, but Apple has had years to crunch the numbers. Besides, I’d be happy with even a rough estimate.
Apple Park's curved glass panels, which were shipped from a factory in Germany to Cupertino
A recent project at Harvard’s Graduate School of Design may help shed light on the embodied energy problem. In 2014, the school announced that it was creating a Center for Green Buildings and Cities, funded by the Chinese real estate company Evergrande. The center’s most visible project is HouseZero, a former residence in Cambridge retrofitted in collaboration with Snøhetta as a test of how old buildings can be made sustainable. The center has repeatedly claimed that the solar panels on the roof will produce enough power to run the building and offset the energy that went into building it. According to the center’s website, HouseZero will “completely offset carbon emissions from the equivalent energy used throughout the intended lifespan of the house including embodied energy for construction materials. . . . This surplus clean energy is to be fed back into the grid.”
That is an ambitious goal—especially because, as Harvard Magazine reported in 2018, “many tons of concrete mass were added in the floors between stories during its renovation, as heat sinks to stabilize daily temperatures from night to day.” The concrete greatly increased HouseZero’s embodied energy, which illustrates a problem facing architects and engineers: Steps taken to reduce carbon emissions from one source often increase emissions from another.
Even though the center hasn’t reported how much energy the solar panels are generating, journalists have repeated, even amplified, its claims about the project’s energy efficiency. For example, last February, one prominent critic simply repeated the party line that HouseZero "offset[s] the energy used to manufacture, transport, and install the materials for its construction." This claim, completely unsubstantiated, is a kind of misdirection, making the problem of embodied energy seem easier to solve than it actually is. Meanwhile, I have been asking Harvard for more information about the performance of HouseZero for the last six months. The center’s director, Ali Malkawi, finally told me he is preparing to release an estimate of the building’s embodied energy.
This is a step in the right direction. When it comes to making buildings more energy efficient, we need to know what’s possible—and what isn’t. (The latter is as important as the former, because time, money, and energy spent on failed approaches are time, money, and energy diverted from more promising solutions.)
Apple, the Niarchos Foundation, and Harvard’s Center for Green Cities and Buildings all claim—explicitly or implicitly—that that the energy it takes to construct a building isn't a significant concern. The numbers may tell a different story. Which is why journalists need to start asking hard questions about embodied energy, and press for answers. Suggesting that it isn’t a problem, or that it can be solved by a few solar panels, ignores one of the biggest contributors to the climate crisis. As a journalist, I plan to keep reminding architects that they should care about embodied energy, as if our lives depended on it.