Only one of them can be "the greenest office building in the world"
Two lavish office buildings, more than 5,000 miles apart, have recently opened for business. One, the Apple headquarters in Cupertino, Calif., is a donut-shaped building designed by Foster + Partners for a suburban setting. Apple has called it "the greenest building on the planet." The other, the Bloomberg headquarters in London, is an urban building. It, too, was designed by Foster, which has called it "the world's most sustainable office building."
Which building is greener? They can't both claim the title.
Norman Foster, the founder of Foster + Partners, which has earned millions of dollars in fees for designing the two buildings, isn't taking sides. And Apple, despite repeated requests, declined to elaborate on its claims. Bloomberg's spokesman, by contrast, answered questions freely.
So which building is greener? It's worth trying to figure out. That's because buildings are responsible for half of the world's greenhouse gas emissions, as much as all other sources combined. If climate change is to be held to manageable levels, building green, or sustainably, is crucial.
But "green" means different things to different people. If you're worried about water pollution, a building with a water-filtration system may seem very green. But if that system runs on electricity, it makes the building - to those chiefly concerned about climate change - less green.
In my view, minimizing climate change is paramount, so the greenest building is the one that releases the least carbon into the atmosphere.
But which is it? Bloomberg or Apple?
Landscape
In one very superficial way, the Apple campus is the greener of the two. It sits on 180 acres, which, thanks to a landscaping plan so ambitious it caused shortages of some kinds of trees in California, are literally green. But all those trees do surprisingly little for the environment. (Yes, trees sequester carbon from the atmosphere, but slowly.) And their carbon footprint, the amount of CO2 released into the atmosphere in the process of locating them, transporting them, maintaining them at nurseries, transporting them again, replanting them, etc., is vast. The trees, part of Steve Job's vision for the campus, may actually be the least green thing about it.
Transportation
In one less superficial way, the Bloomberg building is the greener of the two. The Apple campus has some 11,000 parking spaces; the architects rightly assumed that most of its 13,000 employees would drive to work. Bloomberg, by contrast, is sited among more than half a dozen subway lines, and virtually everyone who works there will arrive by public transportation, or by bicycle. (The building has no employee parking.)
Embodied energy
Measuring energy used to create a building - known as embodied energy, or more commonly, the building's carbon footprint - is an incredibly complex task. But here are some relevant facts: To build its new headquarters, Apple tore down 26 existing buildings, "wasting" the energy that went into creating them. (True, almost all of the materials from those buildings were recycled, according to Lord Foster.) Then it gathered new materials from all over the world. Notably, the building incorporates 900 panes of insulated glass, 10 1/2 feet high and 36 or 46 feet wide (for the outside or inside of the ring, respectively). The largest curved glass panels ever made, they were shipped from a factory near Munich to a port in crates the size of mobile homes. Then the crates were loaded onto ships, which transported them across the Atlantic Ocean, through the Panama Canal, and up the Pacific Coast to California. Once in port, they were transferred to trucks and driven to the site, where the panels, each weighing more than three tons, were lifted into place.
Bloomberg occupies a formerly vacant site. But it, too, used vast amounts of resources including 600 tons of bronze from Japan and what has been called "a quarry-full of granite from India," transported at substantial cost to the environment. (Bloomberg's spokesman wrote: "After a thorough search for suitable stones, the Indian granite was eventually identified and selected for its durability and because the quarry was able to consistently produce the volume and scale of raw stone block required by the project." As for the Japanese bronze, she wrote: "While transporting bronze from overseas may seem carbon intensive, it is a robust material with longevity - so it is projected that the carbon savings of minimising repair and renewal of building elements during the life cycle of the building will outweigh the transport emissions.")
Ongoing energy consumption
Both buildings are designed to use LEDs (which require far less power than other kinds of lighting), and to be heated by sunlight and cooled by breezes whenever possible. Indeed, both buildings employ the latest energy-saving systems.
Bloomberg, however, gets most of its energy from the electric grid, and in London, that means its electricity comes mainly from burning fossil fuels. It also has its own generator that burns natural gas. (And it has a few solar panels on its roof.)
In Cupertino, Apple is planning to get most of its power from a vast array of solar panels on the donut. But how well that system works has yet to be seen (predictions about such things tend to be overly optimistic). And solar panels themselves have a substantial carbon footprint. So Apple's solar array is no silver bullet.
Do we have a winner?

Bloomberg is better than Apple on transportation. No building on a suburban site, with parking for thousands of cars, is green.
Apple is better than Bloomberg on energy generation, but how much better remains to be seen.
When it comes to energy consumption and conservation, both companies have taken important steps. Some of their innovations will help make other buildings greener.
As to embodied energy, both companies made decisions to import materials (glass, marble, bronze) from thousands of miles away, emitting large amounts of greenhouse gases into the atmosphere.
Because both buildings have an enormous impact on the environment, neither can claim to be really green. True, both buildings are much better than they could have been; Bloomberg, Apple and the Foster firm should be applauded for their efforts. But in an era of climate crisis, those efforts may not be enough.
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Why not leave it to LEED?
There are systems for measuring the "greenness" of buildings. In the U.S., the dominant system is LEED (Leadership in Energy and Environmental Design). LEED is based on a checklist - buildings get points for incorporating certain features, including water and air filtration systems that may make the local environment cleaner but, because they take energy to build and operate, contribute greenhouse gases to the atmosphere.
In the U.K., the leading system is BREEAM (Building Research Establishment Environmental Assessment Method) which is a lot like LEED. Both systems focus on how much energy buildings use once they're complete. They don't devote much attention to embodied energy. But obtaining or making building materials (which can include mining, smelting, milling); transporting those materials; and assembling them on-site, uses vast amounts of energy. Ignoring that energy is ignoring the elephant in the room.
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