A flow controller configured to selectively act as a pump or as a flow regulator for a transport of fluid from a first reservoir to a second reservoir, the flow controller comprising: an inlet connectable to the first reservoir; an outlet connectable to the second reservoir; a pump assembly arranged between the inlet and the outlet and configured to pump fluid through the flow controller from the inlet to the outlet using a pump wheel, thereby transporting fluid from the first reservoir to the second reservoir; a flow regulator assembly arranged between the inlet and the outlet, the flow regulator assembly being configured to allow fluid to flow through the flow controller from the inlet to the outlet, thereby transporting fluid from the first reservoir to the second reservoir, the flow regulator assembly being configured to be selectively set in an electricity generating mode and in a flow decreasing mode, wherein upon being set in the electricity generating mode the flow regulator assembly is configured to generate electricity by transforming flow energy of fluid flowing through the flow controller into electricity using a turbine wheel to provide hydro electrical generation, and wherein upon being set in the flow decreasing mode the flow regulator assembly is configured to deaccelerate the flow of fluid flowing through the flow controller; and a mode controller configured to selectively set the flow controller in a pumping mode, in the electricity generating mode, or in the flow decreasing mode, wherein the mode controller is configured to set the flow controller in the pumping mode, the electricity generating mode, or the flow decreasing mode based on a signal indicative on a pressure difference between the fluid at the inlet and the fluid at the outlet; and wherein a direction of flow of fluid through the pump wheel and a direction of flow of fluid through the turbine wheel are the same. an inlet connectable to the first reservoir; an outlet connectable to the second reservoir; a pump assembly arranged between the inlet and the outlet and configured to pump fluid through the flow controller from the inlet to the outlet using a pump wheel, thereby transporting fluid from the first reservoir to the second reservoir; a flow regulator assembly arranged between the inlet and the outlet, the flow regulator assembly being configured to allow fluid to flow through the flow controller from the inlet to the outlet, thereby transporting fluid from the first reservoir to the second reservoir, the flow regulator assembly being configured to be selectively set in an electricity generating mode and in a flow decreasing mode, wherein upon being set in the electricity generating mode the flow regulator assembly is configured to generate electricity by transforming flow energy of fluid flowing through the flow controller into electricity using a turbine wheel to provide hydro electrical generation, and wherein upon being set in the flow decreasing mode the flow regulator assembly is configured to deaccelerate the flow of fluid flowing through the flow controller; and a mode controller configured to selectively set the flow controller in a pumping mode, in the electricity generating mode, or in the flow decreasing mode, wherein the mode controller is configured to set the flow controller in the pumping mode, the electricity generating mode, or the flow decreasing mode based on a signal indicative on a pressure difference between the fluid at the inlet and the fluid at the outlet; and wherein a direction of flow of fluid through the pump wheel and a direction of flow of fluid through the turbine wheel are the same.