Providing the 50 million Americans with 401(k) plans and IRAs increased opportunity to invest in renewable energy could generate more than $350 billion in new investment over four years, the group says, as well as providing a boost to the overall economy, job creation and lower energy costs. The initiative is in the midst of a campaign to encourage companies across the country to add existing publicly traded renewable energy funds to their 401(k) investment menus. A March poll found that 89% of Americans support increased wind and other forms of renewable energy production, but less than 1% of 401(k) plans and IRAs offer the opportunity to invest, according to Ken Beitel, a TREI organizer based in Denver. In response, TREI has promoted its mission by declaring this "National Renewable Energy 401(k) Month," making the announcement at the Annual International Conference on Energy, Logistics and the Environment, sponsored by the Global Commerce Forum. Mainstream investments in wind and solar, notably by Google ( GOOG) and Yale University, has been a boon for their cause, Beitel says. "Having Google invest $5 billion in offshore wind projects helps demonstrate the financial viability of the industry," he says, although he feels more outreach is needed. "What we are seeing right now is that most people don't know that publicly traded renewable energy funds exist. They don't know that they can be added to a 40(1)k plan, and most people don't realize the huge commercial nature of the renewable energy sector. Over the last two years, more than 40% of new electricity has been generated by renewable energy, including solar and wind, but people tend to think it is responsible for just 1% to 2% of new American electricity." Beitel suggests that investors allot no more than 5% of their retirement portfolio. Demand for "green" investments could attract younger investors, he adds. "Currently only about half of 401(k) plan providers offer a renewable energy choice," he says. "Right now we see incredibly low participation rates for people in their 20s, just when it would be most advantageous for them to make a contribution to their retirement. By adding a renewable energy choice, this may prompt more people to invest." Among the frunds TREI suggests as worthy of consideration for 401(K) plans and IRAs: Calvert Global Alternative Energy Fund ( CGAEX); Powershares Wilderhill Clean Energy Index ( PBW); PowerShares Global Wind Energy ( PWND); PowerShares Cleantech ( PZD); PowerShares Global Clean Energy ( PBD); Guinness Atkinson Alternative Energy; Market Vectors Solar Energy ( KWT) and Claymore/MAC Global Solar Energy ( TAN). -- Written by Joe Mont in Boston. >To contact the writer of this article, click here: Joe Mont. >To follow the writer on Twitter, go to http://twitter.com/josephmont. >To submit a news tip, email: email@example.com.