NOVELTY - The self-contained, solar-powered energy supply and storage system comprises an array of solar cells for converting solar energy to electric energy, a direct liquid fuel cell for converting electric energy to liquid fuel, a unit for converting the liquid fuel to electric energy, a liquid fuel storage tank, and a unit for converting carbon dioxide. The unit for converting the liquid fuel to electric energy comprises the direct liquid fuel cell in reverse operation, a reformer for reforming the liquid fuel to hydrogen and/or a hydrogen fuel cell, and/or a high-efficiency turbine generator.    USE - The self-contained, solar-powered energy supply and storage system is useful for supplying on-demand electric power to a power consumption system such as office buildings, residential dwellings and village communities.    ADVANTAGE - The durable self-contained, solar-powered energy supply and storage system is capable of economically supplying on-demand electric power to the power consumption system with high safety.    DETAILED DESCRIPTION - The self-contained, solar-powered energy supply and storage system comprises an array of solar cells for converting solar energy to electric energy, a direct liquid fuel cell for converting electric energy to liquid fuel, a unit for converting the liquid fuel to electric energy, a liquid fuel storage tank, and a unit for converting carbon dioxide. The unit for converting the liquid fuel to electric energy comprises the direct liquid fuel cell in reverse operation, a unit for reforming the liquid fuel to hydrogen and/or a hydrogen fuel cell, and/or a high-efficiency turbine generator. The unit for converting carbon dioxide is the direct liquid fuel cell or a catalytic thermo-conversion reactor, where carbon dioxide is produced from a renewable source by converting biomass or by capturing carbon dioxide from air. The carbon dioxide is captured from flue gas or from biogas produced from agricultural, municipal or domestic waste. The liquid fuel is methanol. The direct liquid fuel cell is a reversible direct-methanol fuel cell (16, 21). The direct-methanol fuel cell has an electricity production mode and a methanol production mode, and produces water vapor and carbon dioxide in the electricity production mode, where the produced carbon dioxide is sequestered from water vapor and stored. In the methanol production mode, carbon dioxide is supplied to an anode to form methanol and the reversible direct-methanol fuel cell produces hydrogen at the anode, where the hydrogen is led to a reactor for reaction with carbon dioxide in the presence of a catalyst to form methanol. The anode is the catalyst for reacting hydrogen and carbon dioxide to form methanol. The catalyst comprises a frustrated Lewis pair. An INDEPENDENT CLAIM is included for a process of supplying on-demand electric power to a power consumption system.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of a self-contained, solar-powered energy supply and storage system.    Roof (11)    Solar panels (12)    Switch (15)    Reversible direct-methanol fuel cell (16, 21)    Conduit. (17)