Development and Test of Solutions to Enlarge the Power of PV Irrigation and Application to a 140 kW PV-Diesel Representative Case

The current state of the art of photovoltaic (PV) irrigation systems is limited to PV peak powers below 40 kWp, which does not cover the irrigation needs of farmers, co-operatives, irrigator communities, and agro-industries. This limitation of power is due to two main technical barriers: The quick intermittence of PV power due to the passing of clouds, and the maladjustment between PV production and water needs. This paper presents new solutions that have been developed to overcome these barriers and their application to the design and performance of a 140 kWp hybrid PV-diesel system for the drip irrigation of 195 ha of olive trees in Alter do Chao, Portugal. The performance of the solutions was analysed during two years of real operation. As the performance of the PV system is not only affected by intrinsic-to-design characteristics, but also by circumstances external to the system, new performance indices were developed. As an example, the percentage of use of PV electricity, PVS H , was 78% and 82% in 2017 and 2018, respectively, and the performance ratio of the PV part, PR PV , was 0.79 and 0.80. The economic feasibility was also analysed based on experimental data, resulting in savings in the levelized cost of electricity of 61%.