Mondo Macchina Nr. 7-9 - Anno 2022

n. 7-9/2022 53 TECHNOLOGY Agrophotovoltaics, technologies for harmonic agricultural land management Growing demand for electricity and increased attention to sustainable solutions have led to increased areas dedicated to photovoltaic installations. One of the main challenges for the coming years will be the coexistence between areas covered by photovoltaic panels and land used for agricultural production Photovoltaic panels The photovoltaic panels can be made up of numerous modules, consisting of several photovoltaic cells, capable of directly converting solar radiation into electricity to be harnessed on-site and/or fed into the grid, thanks in part to the intervention of an inverter. Such technology has made considerable strides in terms of conversion efficiency. The main types of a photovoltaic panel, based on silicon, can be amorphous material (cheapest, with an efficiency of about 8%), polycrystalline (with an intermediate cost and an efficiency that is almost double around 15-17%), and monocrystalline (the most expensive, but with the best efficiency, of 18-21%. Alongside these established types, HCPV (High Concentration PhotoVoltaic) cells have also been added in recent decades. They rely on the concentration of solar radiation through a lens, thus reducing the amount of silicon used per individual panel while increasing efficiency by up to 30%. Defining the efficiency of the system also depends on the orientation and exposure of the panel concerning solar radiation: in addition to fixed plants, there are also (primarily largescale) solar-tracking plants, in which individual units, generally of smaller in size than those of fixed plants, can orient themselves to follow the position of the sun, thus constantly maximizing the intercepted radiation, in addition to fixed plants. A further differentiation concerns stand-alone or grid-connected installations: in the first case, electricity is transferred exclusively to storage batteries, while in the second case, there are fixed locations where all or part of the electricity produced is fed back into the grid. Besides better energy conversion, increased cell efficiency reduces the area occupied for the same amount of electriczione di cui si avvalgono ormai da diversi decenni le abitazioni private ed alcuni impianti aziendali. I pannelli fotovoltaici Le pannellature fotovoltaiche possono essere costituite da numerosi moduli, a loro volta composti da diverse celle fotovoltaiche, in grado di trasformare direttamente la radiazione solare in energia elettrica da sfruttare in loco e/o da immettere in rete, grazie anche all’intervento di un inverter. Tale tecnologia ha fatto passi da gigante in termini di efficienza di conversione. I principali tipi di pannello fotovoltaico, a base di silicio, possono essere in materiale amorfo (più economici, con un rendimento di circa l’8%), in policristallino (con un costo intermedio e un rendimento pressoché doppio, intorno al 15-17%), e in monocristallino (i più costosi, ma con il rendimento migliore, del 18-21%). Accanto a queste tipologie già affermate, negli ultimi decenni si sono aggiunte anche le celle HCPV (High Concentration PhotoVoltaic), che si avvalgono della concentrazione della radiazione solare tramite una lente, riducendo così la quantità di silicio impiegata per singolo pan-