Hybrid PV Systems for the use of Total Solar Energy

Studies have shown the advantages of the "solar-Diesel" hybrid systems compared to other models of fuel savers for telecommunication stations distant from commercial power lines. With a much smaller initial investment, practically the same reliability can be obtained as with 100 percent solar solutions. The idea is to put to use all the available energy of the sun with fewer solar panels (curve 2 on Fig. l), which may be called "Total Solar Energy System". Of course, it is necessary to maintain within the limits of a reliable operation the minimum state of charge of the battery. In practice this can be achieved by the use of a battery charger (Diesel-group or other) and a control system. The results are shown in two different diagrams, which can be used to make the project of hybrid solar systems. The formulas permit us to calculate, for a given site and system, all operational characteristics such as: - state of charge of the battery at the end of each month - monthly number of operation and operating time of the charging group - economy in fuel compared to 100% Diesel system Practical data and results in Brazil have proved the theory. (The above idea was first presented to the Commission of Alternative Energy Sources of Telebras in February 1981. It was partly published in Portuguese in the quarterly publication Revista Telebras in its September 1983 issue).