olar energy is one of the greatest investing opportunities of our generation with well over a trillion dollars in annual market potential around the world. But with all that potential comes tremendous risk, particularly as new technologies emerge.

Over the past decade, we've seen solar technologies rise and fall and companies have risen and fallen along with them. Now that this industry is competing with fossil fuels on a cost per kW-hr basis it's important to look at what technologies dominate the industry and what investors should be betting on in the future.
 

Massive solar farms like this one from SunPower are now competitive with other energy sources on the grid, opening up a huge opportunity for the solar industry. Source: SunPower.

Silicon solar, the leader in the clubhouse 
The vast majority of solar panels today are made using silicon semiconductor technology. At its core, this technology has been around for decades, it just hasn't been efficient or cheap enough to be economically viable versus the grid. But that's changed in the last few years as panel prices have plummeted below $1 per watt.

Inside a silicon solar cell the sun's energy excites the semiconductor, knocking an electron loose. If properly built, a cell then captures that electron and turns it into a voltage potential and electric current.  cont'd..