World's greenest skyscraper

pearl_river_tower.top.jpg1. The Pearl River Tower 2. Solar roof panels 3. Power-generating wind turbines 4. Capturing heat from the sunBy Brian Dumaine, assistant managing editor


(Fortune Magazine) -- The Holy Grail of modern architecture is to design a zero-energy building, or ZEB.

ZEBs use solar, wind, and geothermal systems to produce at least as much energy as they tap from the grid. In some cases, a building's owner can sell the excess electricity generated by the structure back to its utility, reducing overall demand for power generated by coal and other greenhouse-gas-emitting plants.

Yet ask any architect and you'll get an earful on the design challenges of ZEBs. (Skyscrapers don't have much roof space for solar panels, for example.) In fact, there are only eight nonresidential ZEBs in the U.S. -- all of them tiny.

That didn't deter Chicago-based architecture firm SOM from trying. It designed the Pearl River Tower, a 71-story skyscraper in Guangzhou, China, that will open this fall.

China National Tobacco, the owner, wanted a ZEB for its energy cost savings (Pearl River will be 58% more energy efficient than conventional skyscrapers) and the green cred.

SOM did run into some obstacles. For one, the building was meant to have a geothermal system, but the site didn't generate enough warm ground water for it to work. Even so, when the building is fully operational, says SOM, it will be the world's most efficient skyscraper.

What Gives the Tower Power

Keeping cool. Tall buildings use most of their energy trying to keep their inhabitants cool. Even in cold climes, towers run their AC systems most days of the year to counteract the heat from lighting, computers, and workers.

Solar panels on Pearl River's roof (see image No. 2, above) provide power to perforated metal window blinds that automatically track the sun and open and close to minimize solar heat.

Tapping free fuel. Pearl River isn't the first tower to sport electricity-generating wind turbines. What's unique is that its helical turbines (image No. 3), which are inside four openings on the skyscraper's face, will generate power in relatively mild winds from multiple directions.

The turbines, tested in winds as high as 140 mph, will generate up to 4% of the building's power.

Beauty is skin deep. The exterior walls of Pearl River hide an eight-inch air gap inside them (image No. 4). When the sun beats through the double-glazed outer skin, the heat -- instead of entering the interior -- is trapped in this cavity and then rises to heat exchangers on the equipment floors. This, with other features, lets the building use an AC system that is 80% smaller than those in conventional skyscrapers. To top of page

Frontline troops push for solar energy
The U.S. Marines are testing renewable energy technologies like solar to reduce costs and casualties associated with fossil fuels. Play
25 Best Places to find rich singles
Looking for Mr. or Ms. Moneybags? Hunt down the perfect mate in these wealthy cities, which are brimming with unattached professionals. More
Fun festivals: Twins to mustard to pirates!
You'll see double in Twinsburg, Ohio, and Ketchup lovers should beware in Middleton, WI. Here's some of the best and strangest town festivals. Play
Company Price Change % Change
Bank of America Corp... 16.15 0.00 0.00%
Facebook Inc 58.94 0.00 0.00%
General Electric Co 26.56 0.00 0.00%
Cisco Systems Inc 23.21 0.00 0.00%
Micron Technology In... 23.91 0.00 0.00%
Data as of Apr 17
Index Last Change % Change
Dow 16,408.54 -16.31 -0.10%
Nasdaq 4,095.52 9.29 0.23%
S&P 500 1,864.85 2.54 0.14%
Treasuries 2.72 0.08 3.19%
Data as of 7:11am ET
Sponsors

Sections

Spencer has been a supporting member of the "Good Morning America" cast for the past three years. More

Obamacare sign ups hit 8 million, though final enrollment remains to be seen. More

Office for iPad move is a symbolic victory for Nadella's Microsoft, but the company is still weighed down by many of the same old issues. More

Schwinn, Trek and Cannondale are all iconic American bicycle brands. But none of them are made in the United States. More

As Detroit moves closer to reaching a bankruptcy deal, retired civilian workers are poised to be left worse off than firemen and police officers. More

Market indexes are shown in real time, except for the DJIA, which is delayed by two minutes. All times are ET. Disclaimer LIBOR Warning: Neither BBA Enterprises Limited, nor the BBA LIBOR Contributor Banks, nor Reuters, can be held liable for any irregularity or inaccuracy of BBA LIBOR. Disclaimer. Morningstar: © 2014 Morningstar, Inc. All Rights Reserved. Disclaimer The Dow Jones IndexesSM are proprietary to and distributed by Dow Jones & Company, Inc. and have been licensed for use. All content of the Dow Jones IndexesSM © 2014 is proprietary to Dow Jones & Company, Inc. Chicago Mercantile Association. The market data is the property of Chicago Mercantile Exchange Inc. and its licensors. All rights reserved. FactSet Research Systems Inc. 2014. All rights reserved. Most stock quote data provided by BATS.