*Review* **Compatibility between Crops and Solar Panels: An Overview from Shading Systems**

### **Raúl Aroca-Delgado 1, José Pérez-Alonso 1, Ánge<sup>l</sup> Jesús Callejón-Ferre 1,\* and Borja Velázquez-Martí 2**


Received: 14 January 2018; Accepted: 6 March 2018; Published: 8 March 2018

**Abstract:** The use of alternative energy in agricultural production is desired by many researchers, especially for protected crops that are grown in greenhouses with photovoltaic panels on the roofs. These panels allow for the passage of varying levels of sunlight according to the needs of each type of crop. In this way, sustainable and more economic energy can be generated than that offered by fossil fuels. The objective of this work is to review the literature regarding the applications of selective shading systems with crops, highlighting the use of photovoltaic panels. In this work, shading systems have been classified as bleaching, mesh, screens, and photovoltaic modules. The search was conducted using Web of Science Core Collection and Scopus until February 2018. In total, 113 articles from scientific journals and related conferences were selected. The most important authors of this topic are "Yano A" and "Abdel-Ghany AM", and regarding the number of documents cited, the most important journal is Biosystems Engineering. The year 2017 had the most publications, with a total of 20, followed by 2015 with 14. The use of shading systems, especially of photovoltaic panels, requires more crop-specific research to determine the optimum percentage of panels that does not reduce agricultural production.

**Keywords:** sunlight; shading; greenhouse; solar panels; renewable energy
