While renewable energy still has a long way to traverse before it competes on an apples-to-apples basis with hydrocarbon-based fuels, plenty of inroads have been built. Still, Southern  (SO 0.90%) CEO Tom Fanning recently outlined three limitations with renewable energy. Holding back the sector are long distances from demand centers, intermittent supply, and government subsidies.  

Some recent players in the solar industry are working to solve the first problem, but more uncertainty surrounds the later two. Check out the following video for more insight into the future sustainability of renewable energy sources.