By Ian Wyatt NEW YORK ( TheStreet) - The concept of creating energy from nothing seems similar to the dream of Middle Age alchemists who tried to conjure up gold from thin air. Except for one thing, in the 21st Century, generating energy from non-fossil fuel sources is the real deal. Now there is wind power, solar power and other low-polluting ways to generate electricity -- and all are important as demand for electric power puts pressure on the modern grid. The U.S. Energy Information Administration estimates that global electricity demand will reach 28.9 trillion kilowatt-hours by 2025, up from 18 trillion kWh in 2006. In a little known index I found a company that's involved in one of the former trendy energy technologies that has fallen out of favor in recent years. Yet the company I found was one of the hottest stocks at the end of 2010 on my secret index -- the Russell 2000. Interest appears to be growing in fuel cells, and FuelCell Energy ( FCEL) is heating up with investors. The stock's return in the final three months of the year was 104 percent, making FuelCell Energy the second-best performer on the Russell 2000 as of December 31.