Challenges in solar power generation

One of the most promising renewable energy technologies is solar power which allows generating electricity from free, unlimited sunlight. It’s one of the rapid growth industry and technology which contributes significantly to homeowners and commercial industry. It would be a reasonable and useful solution for new power generation installations in developing countries to be powered by carbon emission free sources like solar.  Solar seems perfect for countries with lots of sun exposure and no efficient way of bringing the conventional power grid to remote locations.  But solar still faces a number of obstacles before it can really replace fossil fuels for power generation. However, there are many unexpected challenges with solar electrification that entrepreneurs are learning about while doing business in these developing countries. The Levelized Cost of Solar PowerLevelized cost of Solar Power is a term which describes the cost of the power produced by solar over a period of time, typically the warranted life of the system. It is the capital cost for solar power plants which is high initially. Moreover, there are on-going maintenance costs for both types and the cost of financing any loans.Intensity of Solar RadiationIntensity of solar radiation is one of the main obstacles to the extensive application of solar power. It varies with different locations of the world. The amount of useful solar energy incident in any particular location is highly dependent on latitude and climate. The equator receives the most annual solar energy and the poles receive the least. Dry climates receive more solar energy than those with cloud cover.Required Land SpaceA good amount of land space is required for solar farms, as power generation is directly proportional to the surface area covered. Therefore, the largest solar farms in the world are built in deserts and huge open spaces. However, this is not feasible in smaller countries with limited landmass, or even for larger countries where a land compromise develops restricting the use of agricultural land for developing solar farm.Transmission Sufficient transmission is required to transport the power to urban load centres. Intermittent resources like solar can pose distinctive problems in transmission planning and in efficient operation of transmission infrastructure, causing in higher transmission costs, increased congestion, and even generation limitations when sufficient transmission capacity is not available. Due to potential transmission barriers, solar project developers will need to evaluate the economic trade-off of locating where the resource is best versus locating nearer to loads where transmission barriers are less possible.ReliabilityReliability is one major problem with solar power. A solar panel can produce electricity for maximum 12 hours a day and a panel can only reach peak output for a short period around noon. Solar panels with tracker can track the sun spreading the major generation period fairly, but it still means that panels employ very little of the day producing at maximum capacity. During peak generation, storage batteries can be charged by solar panels which help to supply a dribble of power at night. But they can be costly, contain toxic materials and wear out rapidly due to frequent charging and discharging cycles.Efficiency of Solar PanelPhotovoltaic efficiency is another obstacle. In the desert area, a single square meter of solar panel could receive the equivalent of more than 6 kilowatt-hours of energy in the course of a single day. But a solar panel cannot convert that much of energy to electricity. The efficiency of a solar panel regulates usable power. Most commercial solar panels have efficiency less than 25%. The more efficient a panel is, the more expensive it is to produce.Environmental IssuesThough generating power from solar is free from carbon emission, manufacturing of solar panels and associated technologies can comprise some environmentally unfriendly elements. Nitrogen trifluoride is a common by product of electronics manufacture; including those used in solar cells, and it is a greenhouse gas 17,000 times more potent than carbon dioxide. Moreover, many solar cells contain small amounts of the toxic metal cadmium, and the batteries required to store generated electricity can contain a host of other heavy metals and dangerous substances. As solar technology improves, manufacturers may be able to move away from these potentially dangerous substances, but for now, they ruin the otherwise notable environmental benefits solar power offers.

https://creategreenplanet.blogspot.com/feeds/2195479220720995015/comments/default

How solar panels are made

A solar PV module contains solar cells, glass, EVA, back sheet and frame.Three types of solar panels are available in the market. They are:    Mono-crystalline solar panels    Poly-crystalline solar panels    Thin film solar panelsTherefore, various types of materials are used for manufacturing at cell structure level. They are - mono silicon, poly silicon or amorphous silicon. Mono and Poly crystalline cells have almost similar manufacturing process. For producing a crystalline solar panel following steps are followed:First Step: SandHere sands are used as a raw material. Most solar panels are made of silicon, which is the main component in natural beach sand. Silicon is plentifully available which is the second most available element on Earth. However, converting sand into high grade silicon is a high cost energy intensive process. Pure silicon is produced from quartz sand in an arc furnace at very high temperatures.Second Step: IngotsBasically, the silicon is collected in the form of solid rocks. Hundreds of these rocks are being melted together at very high temperatures in order to form ingots in the shape of a cylinder. A steel, cylindrical furnace is used for forming desired shape. All atoms need to be perfectly aligned in the desired structure and orientation during melting process. For providing the silicone positive electrical polarity, Boron is added to the processMono crystalline cells are manufactured from a single crystal of silicon. Mono Silicon has higher efficiency in converting solar energy into electricity, therefore the price of mono crystalline panels is comparatively higher.Poly silicon cells are made from melting several silicon crystals together. After the ingot has cooled down, grinding and polishing are being performed, leaving the ingot with flat sides.Third Step: WafersIn this step, wafers are used during manufacturing process. The silicon ingot is sliced into thin disks, also called wafers. A wire saw is used for precision cutting. The thinness of the wafer is similar to that of a piece of paper. As pure silicon is shiny, it can reflect the sunlight. An anti-reflective coating is put on the silicon wafer for reducing the amount of sunlight lost.Fourth Step: Solar cellsTreating each wafer, metal conductors are added on each surface. The conductors provide the wafer a grid-like matrix on the surface. This confirms the conversion of solar energy into electricity. The coating will ease the absorption of sunlight, rather than reflecting it. In an oven-like chamber, phosphorous is being diffused in a thin layer over the surface of the wafers. This will charge the surface with a negative electrical orientation. Boron and phosphorous combination will provide the positive - negative junction, which is very important for the proper function of the PV cell.Fifth Step: From Solar Cell to Solar PanelIn this step, using metal connectors, the solar cells are soldered together to connect the cells. Solar panels are made of solar cells integrated together in a matrix-like structure. The current standard offering in the market are:    48 cell panels - For small residential roofs.    60-cell panels - The standard size.    72-cell panels - For large-scale solar power plant.After putting the cells together, a thin layer (about 6-7 mm) of glass is added on the front side, facing the sun. Highly durable, polymer-based material is used to make the back sheet. This will protect solar panel entering water, soil and other materials from the back. For enabling connections inside the module, the junction box is added.After assembling the frame, it all comes together. The frame protects the panel from impact and weather. The use of a frame will also allow the mounting of the panel in a variety of ways, for example with mounting clamps. EVA (ethylene vinyl acetate) is the glue which binds everything together. It is crucial that the quality of the encapsulation is high so it doesn't damage the cells under harsh weather conditions.Sixth Step: Testing the ModulesFor ensuring expected performance of the cells, testing is carried in this step. perform as expected. STC (Standard Test Conditions) are used as a reference point. The panel is put in a flash tester at the manufacturing facility. The tester will deliver the equivalent of 1000W/m2 irradiance, 25°C cell temperature and an air mass of 1.5g. Electrical parameters are written down and these results can be found on the technical specification sheet of every panel. The ratings will reveal the power output, efficiency, voltage, current, impact and temperature tolerance.Beside STC, every manufacturer uses NOCT (nominal operating cell temperature). The parameters used are more close to ‘real life’ scenario:  open-circuit module operation temperature at 800W/m2 irradiance, 20°C ambient temperature, 1m/s wind speed. The ratings at NOCT can be found on the technical specification sheet.Before shipping the module to homes or businesses, cleaning and inspection are done which is the final step of the production.The aim of the research and development in the solar energy industry is to reduce the cost of solar panels and increase the efficiency. The solar panel manufacturing industry is becoming more viable and is predicted to become more popular than conventional sources of energy like fossil fuels.

https://creategreenplanet.blogspot.com/feeds/4222953026789544210/comments/default

How to install solar panels

In order to generate electricity for both commercial and home use, solar panels are used. For getting maximum possible sunlight and generate maximum electricity from the system, photovoltaic panels are installed on the roof top in both cases. Following steps are followed in the installation process:First Step: Installing Mounting Structures of Solar PanelsIn the first step, the mounts are required to be fixed for supporting the solar panels. It can be Roof-ground mounts or flush mounts which dependent on the requirement. This base structure provides support and strength.  Precaution is taken on direction in which the PV panels (mono crystalline or poly crystalline) will be installed. The best direction to face solar panels is south for countries in the Northern Hemisphere because it gets maximum sunlight. East and West directions will also do. On the other hand, the best direction is north for countries in the Southern Hemisphere. The mounting structure needs to be slightly tilted. Angle of the tilt depends on the latitude of the location. Typically, it is in between 18 to 36 Degree. In order to increase the conversion efficiency, a solar tracker can be used. Second Step: Solar Panels Installation In the second step, solar panels are required to be fixed with mounting structures. By tightening nuts and bolts, the installation process can be done. Precaution is taken to secure the whole structure appropriately so that it is robust and persists extended. Third Step: Electrical Wiring In the third step, electrical wiring is done. Universal Connectors such as MC4 are used during wiring as these types of connectors can be connected with all type of solar panels. These panels must be electrically connected with each other in following series:Series Connection: In this type of connection, the Positive (+) Wire is of one PV module is connected to the Negative (–) Wire of another module. This type of wiring increases the voltage match with the battery bank.Parallel Connection: In this type of connection, Positive (+) to Positive (+) and Negative (–) to Negative (–) connection is done. In this type, wiring voltage of each panel remains same.Fourth Step: Connecting the System to PV InverterIn the fourth step, the system is required to be connected to a PV inverter. The Positive wire from the solar panel is connected to the Positive terminal of the inverter and the Negative wire is connected to the Negative terminal of the inverter. In order to generate electricity, the PV inverter is then connected to the Solar Battery and Grid input. Fifth Step: Connecting PV Inverter and Solar BatteryIn the fifth step, the PV inverter and the solar battery are required to be connected. The positive terminal of the battery is connected with the positive terminal of the inverter and negative to negative. In order to store electricity backup, battery is required in off grid solar system.Sixth Step: Connect Solar Inverter to the Grid In the sixth step, the inverter is required to be connected to the grid. For creating this connection, a normal plug is used to connect to the main power switch board. For supplying electricity to the home, an output wire is connected with electric board. Seventh Step: Starting PV Inverter After completing all the electrical wiring and connections, the PV inverter is required to be switched ON the Main Switch of the Home. Digital display of the PV inverter shows you stats regarding generation and usage of solar unit.

https://creategreenplanet.blogspot.com/feeds/7150363668890156923/comments/default