The BIGGEST problem with clean energy

Reduced and more efficient use is as important as storage. Toyota isn't going to like it, but far fewer autos are really needed in well-designed urban areas, not that there are well designed urban areas in North America. This is not only a fuel issue - each car requires a lot of energy to extract and process raw materials as well as to form and assemble vehicles.

Prior to the dismantling of urban transportation networks in the 1960s, people took busses, trolleys, or trains to work. My grandparents (who lived in D.C.) never owned a car. If they needed to go to the grocery store, they would take a taxi, although, during the summer, a vegetable vendor would bring produce from his farm. 

Unfortunately, few new developments are geared towards reduction of energy use. Not only is physical development needed, but changes in personal behavior are going to be needed if we are to achieve a realistic carbon-free energy system.