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The earth is full of safe, stable places to store gases we don't want, and scientists know precisely where they are. The natural gas that heats homes, fires stoves and runs factories is found in deep, saline-rich limestone and sandstone cavities, where spongelike pores store gas and help keep it from leaking away. When the energy industry pumps a deposit clean, the chambers stand empty. Not only are the shape and capacity of the cavities mapped, but also in many cases equipment is still on hand that could easily be repurposed from extraction to injection.
The U.S. Department of Energy is funding seven research partnerships to test sequestration technologies. This summer, one of those projects will inject a modest 2,000 metric tons of CO2 into the sandstone subsurface beneath a spread of tomato fields near Thornton, Calif., where it would stay, in effect, forever.
Would that be safe? Carbon dioxide can be lethal, a fact grimly illustrated in 1986 when a giant surge of the stuff bubbled up from Lake Nyos in Cameroon, asphyxiating 1,700 people as they slept. Nonetheless, investigators involved in the Thornton project insist there is little cause for worry. "The fields held oil and gas for millennia," says Larry Myer, an earth scientist with Lawrence Berkeley National Laboratory in Berkeley, Calif., and the project's director, "so geologically we know they're going to hold CO2."
Even if researchers master the mechanics of sequestration, they must still develop a way to separate CO2 from power-plant exhaust so that there will be something to stash in the cavities in the first place. There are two promising methods. One is to gasify coal before it's burned, reducing it to a high-pressure synthetic gas that can be stripped of its carbon, leaving mostly hydrogen behind. The alternative is to pulverize coal as power-plant operators do now but then rely on new hardware to separate the CO2 after burning. Both methods are at least 20 years away from being fully developed, predicts Ernest Moniz, co-director of the M.I.T. Laboratory for Energy and the Environment and a former Under Secretary of the Department of Energy. "We're very early in the process," he says.
Building a Better Skyscraper
If you want to see what the future of architecture looks like, take a look at the new federal building in San Francisco, but don't look too long. If you're like a lot of folks, you won't much care for it. The glinting, 18-story steel tower jangles badly against the gentle skyline of San Francisco, but it's beautiful on the inside. There's the absence of conventional heating and air conditioning in 70% of the floor space. There's the natural light that fills the workspace during much of the day. There are the windows that actually open and close, and the awninglike fins that filter out heat and glare.
It's easy to overlook how important a building like this one could be. While the power and auto industries get the bulk of the blame for the planet's carbon crisis, the business of operating office buildings and homes is responsible for 38% of U.S. CO2 emissions. In the case of offices, mid--20th century technology worked against us, as the development of low-temperature fluorescent lights and high-powered air conditioning made it possible to design sealed structures that you could drop into any climate. "It gave architects the power to design anything, then hand it over to engineers and say, 'Here, you heat and cool it,'" says Gail Brager of the Center for the Built Environment at the University of California, Berkeley.
The new federal building, by contrast, sits lightly on its site and does so using technology that is available. Computer-operated floor vents open and close automatically in response to temperature sensors; interior walls and cubicle partitions are kept to a minimum to increase circulation; automated panels that filter out glare also help air move around the building, creating what the designers call a circulation engine. "Buildings can use passive as well as active energy," says architect Thom Mayne of the firm Morphosis, which designed the building.
Certainly, if you're going to design a green building, it's smart to do it in San Francisco, where the generally mild weather makes it easier to let your surroundings set your temperature. But what about a place like New York City, with its 100ºF summers and 10º winters? Bank of America is currently tackling that challenge, with a 945-ft. tower in the heart of Manhattan that will use recirculated heat and natural gas to produce some of its own energy and use it more efficiently. Higher ceilings and insulating glass will reduce temperature changes and maximize available sunlight. The basement will even be equipped with a thermal-control system that will manufacture ice in the evenings, when energy demands are lowest, and use it to cool the building during the day, when power plants are running at peak capacity.
The Pearl River Tower, under construction in Guangzhou, China, is aiming for a net energy footprint of zero by relying on such features as on-site wind turbines and recovery and recycling of condensed water. In Paris, a new tower will rely on wind turbines to provide its heating and cooling for the equivalent of five months of the year. And if you're a corporation planning a skyscraper, don't assume you can't afford to go green. The new buildings typically cost about 5% more to construct than conventional ones but quickly exceed that outlay in energy savings. "I think what we're doing now will be commonplace in five years," Mayne says.
The Green Company
When a business with more than 7,000 stores, 1.8 million employees and $345 billion in sales changes its ways, it's hard not to notice. Wal-Mart has made itself the darling of greens with its pledge to install solar panels on many of its stores, switch to hybrid vehicles, conserve water and even buy wild-caught salmon. More important, its mandates are having an incalculable ripple effect through its 60,000 suppliers, which are being asked to join Wal-Mart's effort to reduce packaging, waste and energy use. And when Wal-Mart asks, there's little question what the answer will be.
But Wal-Mart is not alone. In January the U.S. Climate Action Partnership, a group that includes some of the biggest corporate players and energy users in the world--Alcoa, BP America, Duke Energy, General Electric, Lehman Brothers, Caterpillar and PG&E--asked the Federal Government to act aggressively on climate change, not least by imposing legal limits on the amount of industrial carbon dioxide emissions. The corporations know there's a virtue in going green, but they're also looking for some regulatory certainty before they make massive investments. What's more, there's money to be made in the enviro game.