Solar Energy Storage: Researchers at Berkeley Lab have developed a system for converting solar energy to chemical energy and, subsequently, to thermal energy.

FORBES: You Could Be the Next 'American (Geek) Idol'

Until this new system was developed, capturing kinetic energy required converting mechanical energy into electricity, which would then be converted into chemical energy for long- or short-term storage.

FORBES: Battery On Shoe Charges With Every Step

By roughly 2008, carbon microfilament capacitive storage devices were able to match the amount of energy stored per unit volume and per unit weight that chemical batteries were capable of.

FORBES: Game Changer for Tesla

This means that the cost of conversion plus the cost of storage will have to be similar to the cost of providing energy on demand from the energy stored in chemical or nuclear fuels.

FORBES: Storage, Not Generation, is the Challenge to Renewable Energy