Supply and accumulation control process of electrical energy provided by a renewable energy generation plant comprising: - renewable energy generation elements, - control and actuation units of the generation elements, which measure the functional parameters of the generation elements and act thereon, - at least one energy accumulator unit formed by a set of individual systems that are connected in series and in parallel, and - at least one control unit, connected to the control and actuation units of the generation elements, which regulates the energy accumulator unit charging or delivering power depending on the parameters received from the electricity network and on the functional parameters of the generation elements, wherein the process comprises the phases of: - determining the values of energy quantity to be produced by the plant during a near future time interval, depending on weather conditions, - introducing these values of energy quantity, in the control unit, - generating an hourly programme of energy supply to be provided by the energy accumulator unit to the network, by the control unit, and depending on the values of energy to be produced, which: provides stabilization services by stabilizing the power supplied by the plant to the network; provides capacity sales services by providing frequency regulation and voltage regulation services to the network, and provides energy sale services by transfering the energy between off-peak hours and peak hours, or from hours with saturation of the network to hours without saturation, characterized in that the process further comprises a phase of: for the at least one energy accumulator unit, varying the accumulation capacity devoted to capacity sale services, energy sale services and stabilization services in a simultaneous way depending on the weather forecast - renewable energy generation elements, - control and actuation units of the generation elements, which measure the functional parameters of the generation elements and act thereon, - at least one energy accumulator unit formed by a set of individual systems that are connected in series and in parallel, and - at least one control unit, connected to the control and actuation units of the generation elements, which regulates the energy accumulator unit charging or delivering power depending on the parameters received from the electricity network and on the functional parameters of the generation elements, - determining the values of energy quantity to be produced by the plant during a near future time interval, depending on weather conditions, - introducing these values of energy quantity, in the control unit, - generating an hourly programme of energy supply to be provided by the energy accumulator unit to the network, by the control unit, and depending on the values of energy to be produced, which: provides stabilization services by stabilizing the power supplied by the plant to the network; provides capacity sales services by providing frequency regulation and voltage regulation services to the network, and provides energy sale services by transfering the energy between off-peak hours and peak hours, or from hours with saturation of the network to hours without saturation,