Abstract: Due to the intermittent nature of most renewable energy sources (such as solar and wind), practical large scale renewable energy utilization demands both efficient energy conversion and large scale energy storage or alternative usage. Earth-abundant but highly active electrocatalysts need to be developed to enable efficient and sustainable production of energy using electrocatalytic and photoelectrochemical (PEC) water splitting. We developed earth-abundant nanoscale electrocatalysts, such as exfoliated nanosheets of MoS2, for enhancing hydrogen evolution reaction (HER). We established nanotructures of ternary pyrite-type cobalt phosphosulfide (CoPS) as the best earth-abundant HER catalyst in acidic conditions to date. Our recent efforts on the conversion of biomass derived molecules utilizing the increasingly affordable renewable electricity to value-added chemicals will be discussed. Efficient photoelectrochemical hydrogen generation systems that integrate these earth-abundant electrocatalysts with efficient semiconductor materials have been rationally designed and demonstrated. I will also discuss novel hybrid solar-charged storage devices that integrate photoelectrochemical solar cells and redox flow batteries (RFBs). In these integrated solar flow batteries (SFBs), converted solar energy is used to directly charge up the redox couples without external electric bias; which can be discharged to generate the electricity when electricity is needed.