t's encouraging to read reports such as Newsweek's annual review of the "greenest" companies. It's uplifting to learn which companies are taking environmental sustainability seriously. It's also exciting to see that green companies can boost your portfolio as well as your spirits: The top 100 companies from Newsweek's 2009 list outperformed the S&P 500 by nearly 7% in the following year. Here's a thought, though: Maybe the companies at the bottom of the list have a lot to offer, too.

There's a lot to love about the companies at the top. Intel (Nasdaq: INTC), for instance, is ranked fifth out of the 500 companies on Newsweek's list, and for three years in a row it's been the country's top buyer of electricity from renewable sources such as wind and sun. The company expects to save a whopping $25 billion by 2015 with IT initiatives designed to be energy-efficient. Clearly, going green can be a win-win proposition.

Bottoms up
That's what has me looking at companies on the bottom of Newsweek's list with some interest. To a great degree, they're not making the most of their green possibilities. But they can. And when they do, they can reap considerable savings, boosting their profitability and rewarding their shareholders in the process.

Many of the companies near the bottom of the list are resource-heavy, which can make going green harder than it is for less capital-intensive outfits. Cliff Natural Resources (NYSE: CLF), for example, mines iron ore and coal, among other things. Bulls see rising demand for iron ore (such as from China and the automotive industry) and little near-term supply expansion.

But Alcoa (NYSE: AA) is in a similar (though, of course, not identical) business, mining for bauxite with which to make aluminum. And Alcoa sports a much higher green rating (315, versus 490) because of a stronger commitment to the planet. Among other initiatives, Alcoa is developing aluminum paneling that can remove pollutants from the air. It has been recycling aluminum since the 1800s and today demands sustainability from its suppliers. It also publicly lists its aggressive environmental goals and its progress toward meeting them.

There's big money to be saved through environmental initiatives such as energy efficiency. Dow Chemical (NYSE: DOW) estimates that it has saved more than $8 billion since 1994. Thus, when I see companies such as Lorillard (NYSE: LO) near the bottom of Newsweek's list (No. 479), and I see its peers Reynolds American (NYSE: RAI) and Altria (NYSE: MO) ranked much higher (at 229 and 326, respectively), I know that Lorillard can do better and can profit in the process.

Interested investors may want to see how much untapped conservation potential their companies have and to watch for them tapping it. Better still, let your companies know what you'd like to see them doing. Inform them that responsibility won't wreck their returns.

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Longtime Fool contributor Selena Maranjian holds no position in any company mentioned. Check out her holdings and a short bio. The Motley Fool owns shares of Altria Group and Intel and has bought calls on Intel. Motley Fool newsletter services have recommended buying shares of Intel, writing puts in Lorillard, and creating a diagonal call position in Intel. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.