WEBVTT 00:00:00.000 --> 00:00:03.993 What is photovoltaic energy? 00:00:06.000 --> 00:00:08.546 It is the energy produced thanks to the sun. 00:00:09.000 --> 00:00:15.519 Solar irradiance is the measure of the amount of solar radiation that reaches the Earth’s surface 00:00:16.618 --> 00:00:23.336 and it is measured in watts per square meter, with a total value of about 1367 W/m2, called the solar constant. 00:00:24.665 --> 00:00:27.178 Solar photovoltaic power plant - How does energy production take place? 00:00:27.329 --> 00:00:32.298 To convert the radiation into electricity, the panel’s solar cells leverage the photoelectric effect: 00:00:32.811 --> 00:00:37.238 When the light hits the photovoltaic module, the photons stimulate the electrons present in the silicon of the cell, 00:00:37.238 --> 00:00:42.000 producing a current thanks to the physical phenomenon known as the "photovoltaic effect". 00:00:52.579 --> 00:00:53.763 Solar photovoltaic power plant-Let's go into more detail 00:00:53.838 --> 00:00:57.116 The cells connected to each other in series form a module. 00:01:03.121 --> 00:01:07.689 The panel is a set of modules assembled in a common structure. 00:01:07.689 --> 00:01:11.560 The strings are linked to each other in parallel 00:01:11.560 --> 00:01:16.339 and together form the photovoltaic generator. 00:01:19.054 --> 00:01:20.289 What are support structures? 00:01:20.485 --> 00:01:23.906 The panels are housed in support structures 00:01:23.906 --> 00:01:29.455 that guarantee the correct inclination and the right orientation with respect to the sunlight. 00:01:29.455 --> 00:01:30.214 How many types of support structures are there? 00:01:30.214 --> 00:01:33.664 There are two types: fixed and tracker 00:01:34.268 --> 00:01:40.472 -monoaxial: they move to follow the sun exposure every day on a horizontal rotation axis 00:01:40.579 --> 00:01:43.698 -biaxial: they move in all directions 00:01:45.192 --> 00:01:46.384 How many types of photovoltaic modules are there? 00:01:46.384 --> 00:01:47.205 The three most common are: 00:01:47.205 --> 00:01:49.040 Monocrystalline silicon 00:01:49.236 --> 00:01:51.000 Polycrystalline silicon 00:01:51.000 --> 00:01:52.578 Thin film 00:01:52.578 --> 00:01:54.578 Panel efficiency can vary from 15% to 21%. 00:01:57.668 --> 00:02:00.764 Monocrystalline silicon Uniform dark blue colored modules 00:02:00.870 --> 00:02:04.908 with the cell’s crystals all oriented in the same direction 00:02:04.908 --> 00:02:07.604 and arranged in an orderly manner as to form a single crystal. 00:02:09.686 --> 00:02:13.276 Polycrystalline silicon Almost iridescent blue modules 00:02:13.367 --> 00:02:16.786 whose cells are made of silicon crystals oriented in a non-uniform way. 00:02:17.072 --> 00:02:20.437 They are less efficient than monocrystalline 00:02:20.437 --> 00:02:25.517 because they attract less power for the same module surface area. 00:02:27.692 --> 00:02:33.294 Thin film Modules that adapt to work well with diffused light or at high temperatures. 00:02:33.294 --> 00:02:38.475 This type of module is often called amorphous silicon. 00:02:39.240 --> 00:02:40.519 Solar panels are also divided into: 00:02:40.519 --> 00:02:45.126 Monofacial- They capture sunlight only from the front side. 00:02:45.126 --> 00:02:47.876 Bifacial - They capture sunlight from the front side 00:02:47.876 --> 00:02:52.292 using direct light but also that reflected and diffused from the backside of the panel. 00:02:55.191 --> 00:02:58.393 The latter also includes HJT panels 00:02:58.393 --> 00:03:02.864 that leverage innovative heterojunction technology that uses amorphous crystalline silicon, 00:03:02.864 --> 00:03:06.132 setting the world efficiency record of 24,63% in 2020. 00:03:20.909 --> 00:03:21.841 How is electricity produced? 00:03:21.841 --> 00:03:24.228 Junction Box On the back of the panel we find the Junction Box, 00:03:24.228 --> 00:03:29.928 inside which the connections between the electrical metallizations of the panel 00:03:29.928 --> 00:03:34.978 and the external cables that allow the connection between multiple panels take place. 00:03:36.157 --> 00:03:37.276 Let's look in more detail 00:03:37.276 --> 00:03:44.888 The panels, joined in strings, are connected to the inverter which transforms direct current into alternating current. 00:03:45.990 --> 00:03:50.250 The inverter is a system consisting of an IGBT stack, also known as IGBT bridge (Insulated-Gate Bipolar Transistor): 00:03:50.250 --> 00:03:52.498 a device used as an electronic switch. 00:03:53.253 --> 00:03:56.531 It is equipped with MPPT (Maximum Power Point Tracker) algorithms: 00:03:56.531 --> 00:04:00.977 control instruments that fix the operating voltage of the panels 00:04:00.977 --> 00:04:05.061 in order to reach the panel’s maximum power point. 00:04:06.423 --> 00:04:12.000 Once transformed, the alternating current is ready to be distributed through the grid. 00:04:12.517 --> 00:04:13.533 How does the storage system work? 00:04:13.533 --> 00:04:19.015 Energy can also be kept in a storage system that releases energy as needed: 00:04:19.317 --> 00:04:25.570 when there is a high demand, it is able to start delivering the accumulated energy within a few seconds 00:04:25.887 --> 00:04:30.062 during the hours when there is no sunlight it allows a continuous supply of energy 00:04:30.561 --> 00:04:36.226 when there is a drop in demand, it is able to store excess energy in order to avoid waste. 00:04:38.260 --> 00:04:44.614 This ensures a constant supply of energy produced by the photovoltaic system. 00:04:45.614 --> 00:04:48.441 We are now ready to distribute energy 00:04:49.755 --> 00:04:55.193 Through a transformer, the intensity of the current is lowered and the voltage is raised. 00:04:56.406 --> 00:05:00.191 In this way, the current generated is fed directly into the distribution network 00:05:00.311 --> 00:05:02.925 that will power homes and businesses. 00:05:03.831 --> 00:05:05.936 Thanks to solar photovoltaic power plants, 00:05:05.936 --> 00:05:11.334 we can count on an inexhaustible reservoir of renewable energy with zero emissions to power the planet.