We cant limit our generation growth by Renewable sources of energy and we need to divert our relience to Renewable and clean energy sources. also investment in this sector will lead you to better returns as the appretiation of these stocks is much higher than any other asset category.

the global index for this catogary is "The WilderHill New Energy Global Innovation Index(NEX)". it tracks around 80 clean energy companies listed on 25 exchanges worldwide and indexed to 100 at the start of 2003, it had traded as high as 450 at the end of 2007. It remained in the 350-400 range through the first three quaters of 2008, out performing the rest of the world.
The compaunded annual capital appretiation of NEX over the past seven years(from its begining of 2003) to the end of 2009 was still 13.8% - a respectable return when compared with almost any major asset class.

we can see the reference chart of NEX Index and some of its companies. Yahoo! Finance
Quote for NEX