Embracing environmental friendliness doesn't just help Mother Earth. A recent study suggests that companies that go green can also reap a bumper crop of benefits for their bottom lines.

In 2010, Newsweek assembled a list of its top 100 "greenest" companies. Now, research firm Trucost has announced that this group outperformed the S&P 500 Index (on an equally weighted basis) by 6.8 percentage points for the 12-month period ending Sept. 1, 2010.

Even without the ethical enticement of being kinder to the environment, companies increasingly find that going green proves profitable. Among the top 200 companies on Newsweek's list, these familiar names have promising initiatives under way:

  • PepsiCo (NYSE: PEP) has installed 5,600 solar panels on the roof of its Frito-Lay manufacturing plant in Modesto, Calif. During peak production, solar energy will reduce the need for outside electricity by 25%, while also cutting carbon-dioxide emissions by 1,000 metric tons annually. Over the past decade, PepsiCo has reduced electricity use by 19% at the plant, natural-gas use by 30%, and water by 44% (per pound of product).
  • General Electric (NYSE: GE) is planning to buy 25,000 electric vehicles by 2015, both for its own use and to lease to others. If gas prices continue to rise, so will GE's savings from the program. But the company stands to gain in bigger ways. CEO Jeff Immelt explained, "By electrifying our own fleet, we will accelerate the adoption curve, drive scale and move electric vehicles from anticipation to action." GE happens to make electric grid equipment, and it has a stake in manufacturing batteries for electric vehicles as well.  
  • AT&T (NYSE: T) saved $44 million last year by improving its energy efficiency and power consumption management. More than 4,200 different projects collectively delivered that total amount. Among the broad spectrum of efforts, the company installed power management software at its facilities, and replaced light bulbs at more than 1,000 cell sites.
  • Procter & Gamble's (NYSE: PG) Auburn, Maine, manufacturing plant became its first in the U.S. to send zero waste to landfills, and its ninth such plant globally. The company has noted that these efforts save tens of millions of dollars each year.
  • Beyond refining their operations, many companies have begun to make green initiatives their business. Dow Chemical (NYSE: DOW) is building the world's largest bio-derived plastics factory in Brazil, at which the company will convert sugar to polyethylene. It's also working to turn carbon dioxide into ethanol, among other initiatives. Such operations won't just save the company money -- they may actually make it money.

The best companies keep evolving, and right now, many have begun to embrace the benefits of a positive environmental impact. Shareholders who seek out these companies could enjoy a similar boost to their own portfolios.

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Longtime Fool contributor Selena Maranjian owns shares of PepsiCo and Procter & Gamble. AT&T is a Motley Fool Inside Value recommendation. PepsiCo and Procter & Gamble are Motley Fool Income Investor recommendations. Motley Fool Options has recommended a diagonal call position on PepsiCo. The Fool owns shares of PepsiCo. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.