Agriculture has always relied on sunlight and water, that’s a known fact since the birth of civilization. A project initiated in Upper Egypt uses sunlight to extract water from arid land, seeking to replace diesel generators that have traditionally been used.
In Wadi El Natrun, a standalone photovoltaic system provides the power needed to irrigate a wheat field through concentrated photovoltaic modules (CPV).
CPVs need far less space than traditional photovoltaic modules, because they focus the sunlight on an extremely small multijunction PV cell. A sun tracking system attached to a pillar keeps the lenses focusing light onto the cell at their maximum capacity to drive the submersible pump that pulls water from 105 feet beneath the soil.
The CPV system also powers a small desalination unit for providing the farmers with potable water, for all the tracking motors, the monitoring and control system and for an air conditioning system cooling the facility.
“Where there is no public power grid, the PV systems currently operate cost-effectively, due to their low operating costs. The only problems are posed by the high initial costs of the investment, in which the batteries play a substantial role,” explained Jakob Wachtel from the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany. “By immediately using the largest share of the energy that is generated we can save on expensive storage media capacities,” says his colleague, Alexander Schies.
Only a small battery is used to redirect the panels towards the position needed in the morning, and the rest is all live, battery-free electricity.
The physical communication system together with the protocol that the power management system uses have been designed by Fraunhofer to offer maximum flexibility for such applications.