Solar energy supply and storage for the legacy and nonlegacy worlds

Energy storage technology increases the value of all renewable energy supplies whether they are centralized or decentralized. However, centralized (over the grid) or decentralized energy distribution results in different targets for energy storage as a result of different time scales and the nature of the demand. Most grid-based storage mechanisms are mechanical and they span storage needs, with time scales of microseconds to days. The most sustainable source of protons and electrons for solar fuels production is water, which when split by an OER catalyst delivers oxygen and the requisite four electrons and protons needed for fuels production. The electrons and protons may be directly combined to produce H₂ by a HER catalyst or, with future research discovery, combined with CO₂ to furnish a liquid fuel. The best Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER) catalysts are heterogeneous when a normalized comparison of performance is made between homogeneous and heterogeneous catalysts.