Ex 5 DESIGN OF STAND ALONE PHOTOVOLTAIC POWER PLANTS Text

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DESIGN OF STAND-ALONE PHOTOVOLTAIC POWER PLANTS Power production from renewable energy – A.Y. 2020/21 Prof. Paolo Silva – Ing. Dario Alfani It is required to design a photovoltaic plant coupled with a storage system to power a 4G radio station located in a remote area, connected according to the figure below. The sizing aims at identifying the cheapest plant configuration, consistently with the need to guarantee the satisfaction of the daily electrical load throughout the whole year. For the energy storage, an electrochemical system is chosen (lead batteries). Figure 1 – Schematic of the PV plant coupled with the lead batteries storage system. Two options are taken into consideration: case a) minimize the PV plant surface, using a storage sized on an annual basis; case b) minimize the storage size, designing the PV plant such that it can produce the energy required on a monthly basis, even in the least-favourable conditions. The following table shows the climate data and the monthly average temperature for the selected site (Va l Chiavenna, northern Italy) in each month. The average power load from the antenna (DC, 12 V) is 800 W. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average T [°C] -0.5 1.3 4.2 7.7 11.2 14.3 16.6 16.1 13.3 8.6 4.1 0.3 H() [Wh/m2d] 1’890 2’460 3’770 4’430 4’670 5’490 5’840 5’190 4’130 2’800 1’890 1’410 The PV module installed is a NU-RC300, which dimensions are reported in Figure 2 in mm. The NU-RC300 PV module nominal power is 300 Wp, while the average balance-of-system efficiency (charge controller, auxiliary components, …) can be assumed equal to 80%. The electrochemical storage device is characterized by a nominal voltage of 13.2 V, a charging voltage of 13.8 V, and a discharging voltage of 12.8 V. To take into account the self-discharge…