A method, apparatus, and system for an integrated solar- driven chemical plant that manages variations in solar energy are disclosed. In some embodiments, a chemical reactant, including particles of biomass, are converted in a solar driven chemical reactor into synthesis gas containing carbon monoxide and hydrogen using concentrated solar energy to drive the conversion of the chemical reactant. The synthesis gas is supplied for a catalytic conversion of the synthesis gas in a methanol synthesis plant to methanol. Cycling occurs between an operational state and an idle state for a number of methanol trains in the methanol synthesis plant depending upon an amount of synthesis gas generated in the solar driven chemical reactor. A control system for the chemical reactor sends control signals to and receives feedback from a control system for the methanol synthesis plant.