Primer on Solar Electricity for India


Published on

Under JNNSM a Solar electricity program is implemented now.

Published in: Technology
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Primer on Solar Electricity for India

  1. 1. Primer on Solar Power system • Simple Indian perspective • Insolation in India, Photovoltaic conversion, • Cell, Module, Panel, Array- Area exposed • Balance of system components, • Solar Home System, • Solar Lighting, Street Lighting, • Solar Generator, Motor and Water pump • A case Study: Lead kindly Light • Textbooks on SPV science & technology
  2. 2. Insolation in India: An Energy Resource • Solar radiation is perennial, environment-friendly and well suited for decentralized applications. • Most parts of India receive 4–7 kWh (kilowatt-hour) of solar radiation per square metre per day. • There are 250–300 sunny days in a year. • The highest annual radiation energy is received in western Rajasthan.
  3. 3. SUNLIGHT to ELECTRICITY • The photovoltaic route converts the light in solar energy into electricity, which can then be used for a number of purposes such as lighting, pumping, communications, and power supply in unelectrified areas. Solar photovoltaics (SPV) is the process of converting solar radiation (sunlight) into electricity using a device called solar cell.
  4. 4. solar cell
  5. 5. Solar Photovoltaics • A solar cell is a semi-conducting device made of silicon or other materials, which, when exposed to sunlight, generates electricity. • The magnitude of the electric current generated depends on (i) the intensity of the solar radiation, (ii) exposed area of the solar cell, (iii) the type of material used in fabricating the solar cell, and (iv) ambient temperature. • Solar cells are connected in series /parallel combinations_ modules to provide power.
  6. 6. Basic building block for electricity from Light • Solar cells are made of silicon (semiconductors) Treated to be positive on one side and negative on the other. • When light energy hits the cell, electrons are knocked loose from the atoms in the semiconductor material. • If conductors are attached to the positive and negative sides, forming a circuit, the electrons can be captured in the form of an electric current.
  7. 7. Module • Every single photovoltaic cell has small dimensions and generally produces a power between 1 and 3 watts and 0,5Volts, at the standard test conditions (STC) of 1000W/m². • To get a bigger power and voltage, it is necessary to connect several cells among themselves to create bigger units called modules
  8. 8. Panel and Array • The modules, in their turn, can be connected to constitute panels, called photovoltaic fields too, that produce the power wanted from the application. • Therefore the photovoltaic system is a unification of mechanical, electric and electronic components that contribute to capture and transform the available solar energy, for the users of electric energy
  9. 9. The photovoltaic system structures • Systems with fixed inclination - (fixed supporting structure) • Systems with active tracking - single/double axis tracking systems (characterized by step by step motors and control electronics) • Self contained systems or “stand alone” • Network connected systems or “grid connected”
  10. 10. Solar home system -1 • A solar home system (SHS) provides a comfortable level of illumination in one or more rooms of a house. There are several SHS models featuring one, two, or four Compact Fluorescent Lamps (CFL). It is also possible to run a small DC fan or a 12-V DC television with the system.
  11. 11. Solar home system - 2 • The SHS consists of a PV module of 18, 37 or 74 Wp (Watt peak) capacity; a sealed, maintenance-free, or flooded lead–acid battery of 12 V and 20, 40 or 75 AH capacity; and CFLs of 9 W or 11 W rating. The system is designed to provide service for three to four hours daily, with an autonomy of three days, that is, the system can function for three cloudy days.
  12. 12. Operation • A PV module is usually mounted on the roof of the house so that it is exposed to direct solar radiation throughout the day, avoiding any shadow. • The module converts incident radiation into electricity, which, in turn, charges the battery, which is placed inside the house. • The battery provides power to the CFLs, and to the television and/or fan as required. A change controller prevents overcharging and deep discharge of the battery.
  13. 13. SPV Lighting Systems • SPV lighting systems are becoming popular in both the rural and urban areas of the country. • In rural areas, SPV lighting systems are being used in the form of portable lanterns, home-lighting systems with one or more fixed lamps, and street-lighting systems. Applications in urban areas include • glow-sign display systems on the streets, • traffic signaling, message display systems based on light-emitting diodes (LEDs), and • systems to illuminate advertisement hoardings.
  14. 14. Solar Lantern • The solar lantern is a portable lighting system. Being light in weight, it is easy to carry around and therefore ideal for both indoor and outdoor usage. • A typical solar lantern consists of a PV module of 8 Wp to 10 Wp capacity, a sealed maintenance-free battery of 12 V, 7 AH (ampere hours) capacity, and a compact fluorescent lamp (CFL) of 5 W or 7 W rating. A solar lantern is usually meant to provide light for three to four hours daily, and designed to have a three-day „autonomy‟, that is, to function in this manner for three days without sunlight.
  15. 15. Operation: • During the day, the PV module is placed in the sun and is connected through a cable to the lantern unit. • The incident solar radiation is converted into electricity, which, in turn, charges the battery. A green LED light indicates the charging of the battery. At night, the lantern is simply detached and used wherever required. The battery provides power to the lamp. The cost of a solar lantern with the above specifications is in the range of Rs 3000–3300. Low-cost models with smaller PV modules and battery capacity are also available.
  16. 16. Solar street lighting system • A solar street-lighting system (SLS) is an outdoor lighting unit used to illuminate a street or an open area usually in villages. A CFL is fixed inside a luminaire which is mounted on a pole. • The PV module is placed at the top of the pole, and a battery is placed in a box at the base of the pole. The module is mounted facing south, so that it receives solar radiation throughout the day, without any shadow falling on it.
  17. 17. A typical street-lighting system consists of a PV module of 74 Wp capacity, a flooded lead–acid battery of 12 V, 75 AH capacity, and a CFL of 11 W rating. This system is designed to operate from dusk to dawn (that is, throughout the night). The CFL automatically lights up when the surroundings become dark and switches off around sunrise time. The cost of an SLS is about Rs 19 000. Variations in the cost are possible on account of local taxes, additional transportation costs, etc. The Ministry of New & Renewable Energy Sources provides financial assistance for the promotion of some of the above solar lighting systems among eligible categories of users.
  18. 18. Solar Generators • A solar generator is a small capacity, stand-alone SPV power system based on (i) a PV array, connected to (ii) a battery bank and (iii) an inverter of appropriate size. • This system is designed to supply power to limited loads (such as lights and fans) for a period of two to three hours daily in situations such as conventional power failure or load-shedding.
  19. 19. • The MNRE currently promotes four models of solar generators, with capacities of 150, 350, 450, and 600 Wp. • These solar generators are mainly meant to replace the conventional small-capacity petrol-based generators that are used during routine load-shedding periods in urban areas by shops, clinics, and other small establishments.
  20. 20. SPV Pumping System • An SPV water pump is a DC or AC, surface-mounted or submersible or floating pump that runs on power from an SPV array. • The array is mounted on a suitable structure and placed in a shadow free open space with its modules facing south and inclined at local latitude. • A typical SPV water-pumping system consists of an SPV array of 200–3000 Wp capacity, mounted on a tracking/non-tracking type of structure. • The array is connected to a DC or AC motor connected to pump of matching capacity.
  21. 21. • The array is connected to a DC or AC motor connected pump of matching capacity that can be of s u r f a c e - m o u n t e d , submersible, or floating type. Interconnecting cables and electronics make up the rest of the system. • SPV water pumps are used to draw water for irrigation as well as for drinking. The normal pumping heads are in the range of 10 metres (m) for irrigation, and 30 m for drinking water. It is possible to use pumps with even greater head, especially for drinking water supply. The SPV array converts sunlight into electricity and delivers it to run the motor and pump up water. The water can be stored in tanks for use during non-sunny hours, if necessary.
  22. 22. The SPV array converts sunlight into electricity and delivers it to run the motor and pump up water. The water can be stored in tanks for use during non-sunny hours, if necessary. For maximum power output from the SPV array, the structure on which it is mounted should track the sun. Electronic devices are used to do this in some models, thereby enabling the systems to operate at maximum power output. The power from the SPV array is directly delivered to the pump in the case of DC pumps. In the case of AC pumps, however, an inverter is used to convert the DC output of the array into AC. No storage batteries are used in an SPV pump.
  23. 23. An SPV pump based on a one-horsepower motor can irrigate about 1–1.5 hectares of land under a variety of crops except paddy and sugar cane (assuming a 10-m water table). Using the same pump along with drip irrigation, it is possible to irrigate up to 6 hectares of land for certain crops. A two-horsepower SPV pump could irrigate about 2–3 hectares of land under many crops except paddy and sugar cane (again assuming a 10-m water table).
  24. 24. SPV Pumping System • The cost of an SPV pump depends on the capacity and type of pump. For example, a DC surface pump with a 900 W array may cost about Rs 150 000; a similar pump of 1800 W may cost about Rs 300 000; and an 1800 W AC submersible pump may cost about Rs 422 000.
  25. 25. A Case Study: Lead kindly Light • The Solar Electric Light Company (SELCO) designs and sells solar systems that replace kerosene lamps, proving emission free, sustainable power to electric lights and small appliances.
  26. 26. The systems include a small solar photovoltaic (PV) panel, a battery and energy efficient lights. SELCO installs the systems and provides after- sales servicing to ensure the systems continue to deliver benefit. For the families, the solar panels are cheaper to run. They also eliminate the health hazards caused by kerosene fumes, including respiratory infections, lung and throat cancers and serious eye infections.
  27. 27. Oh! Who bears initial cost? • Access to clean, good- quality light also provides increased opportunities for income generation, particularly for women, through basket making, silk weaving and tailoring. • Since the installation cost of a single solar lighting unit is around $300, families living in these rural communities often cannot afford the new systems.
  28. 28. SELCO works in partnership with micro-finance organizations, which allows SELCO‟s customers to pay for the systems on terms they can afford. The savings that householders make in kerosene contribute to the repayment of the loan. The sale of carbon credits from the project helps to subsidise the cost to the customer, by reducing interest rates on loans and financing down- payments.
  29. 29. Text books on PV For further education