Solar Photovoltaics

What is it?

Solar Energy can be directly converted to electrical energy by means of Solar Photovoltaic System. Solar Photovoltaic (SPV) Technology enables the conversion of direct sunlight into electricity without involving any moving part such as turbine etc.The basic part Solar Photovoltaic is known as Solar Cell. Solar Cells are made of semi conducting materials- a thin wafers of Silicon which is exposed to sunlight, to produce D.C electric current.

Solar power and other renewable energy sources are seeing technological advances that are making them cost effective. Rapid growth is projected.

At the moment, photovoltaic power is expensive, but since we will never run out of sunlight, it is an exciting source of energy for the future! Solar water heating systems pay for themselves in three to five years. The technological challenge we face is to find ways to make solar technologies affordable for everyone.

In developing countries the percentage of households which have no access to electricity is more significant. Most of those lacking access live in rural or peri-urban areas. Solar photovoltaic (PV) cell designed to convert light into electricity is often used to cover the electricity need of household.

Households without access – regional decomposition
''Household without access - UrbanHousehold without access - RuralHousehold without access - TotalPersons Per HouseholdPersons without access
China4000130,000134,0004536,000
India360074,00077,6005.5426,800
Rest of Asia15,00078,70093,7005468,500
Africa29,00070,70099,7006598,200
Latin America8,50011,10019,6005.5107,800
Total60,100364,500424,60052,123,000

Source: EDF – October 2002 – Electricity for all: targets, timetables, instruments – World Summit for sustainable development

Solar PV systems provide a wide range of energy services such as lighting, electricity for radio, TV, phone, and water supply for domestic use or activities aimed to increase poor people’s income like agriculture (irrigation). So PV, like other renewable energy systems, has been seen as an alternative to grid extension.

Many reasons justify why the use of solar PV system for solar-based electricity production is an attractive option in electrification of rural and peri-urban households:
  • the abundance of solar resources in most developing countries;
  • the fact of the costs solar PV equipment are gradually falling;
  • the interesting experiences learned in this sector. In the developing world solar PV systems have been tested, optimised and disseminated over the last 20 years;
  • the PV module manufacturer, or module supplier, generally provide a minimum 10-year warranty.
The use of solar PV is being promoted by international organisations (World Bank), various governments through theirs agencies of cooperation (GTZ, JICA, AFD etc), rural electrification agencies, and NGOs.

Who uses it?

Solar the Photovoltaic Energy is part of Rural Revolution in the rural areas where grid power is not yet reached. In India Solar Photovoltaic System is successfully installed in large number of villages.

A household can generate most of the electricity they need with photovoltaic cells on their rooftops. If there isn't enough sunlight at times, electricity can be stored in batteries for cloudy days.

Solar water heating systems pay for themselves in three to five years. The technological challenge we face is to find ways to make solar technologies affordable for everyone.

The SPV system consists of an 800/860 WP (weather permitting) photovoltaic arrangement, a permanent DC magnet motor-driven floating pump which can pump water from a depth of eight meters through the optimum of 6.5 meters. It can ideally function in a wide-mouth well with a flow rate of 70,000 liters a day. The photovoltaic modules on the solar panel captures energy from the sun and converts it into electricity. The panel is connected to the pump via a plug so that the farmer finds it easy to use. The system works as long as there is sunshine. For example in In South India, the sun is of course plentiful.

The uses of Solar PV

Solar home system (SHS) and photovoltaic pumping system (PVP) are the most proven of PV application in the field of household energy. The use of SHS is more significant than PVP.

Solar Home System (SHS)

SHS helps to meet the need of lighting and electricity for Radio, TV, for communication (internet , mobile phone). From experience learned SHS is more advantageous than candles, flashlights, kerosene lamp and car battery system.
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  • PV generator;
  • support structure;
  • charge regulator;
  • battery;
  • loads (lamp, ballast, radio, TV);
  • wiring, installation
  • documentation.

The PV generator or solar photovoltaic cell is the generator. It converts light into electricity. The solar cell array generally consist of one polycrystalline photovoltaic solar module. It should have a rated peak power output of at least 45 Watt peak (Wpeak). Its minimum acceptable operating voltage at maximum power point is no less than 16 Volts at cell operating temperature of 60°C.
The charge regulator or battery control unit (BCU) serves to protect the battery against both deep discharge and overcharging. Its nominal voltage is generally 12 volts.
The battery stores the electric energy produced by the PV generator.
The loads: radio, TV and mobile phone come directly from the users. Electronic DC Ballast and Incandescent lamps are generally substituted for energy-saving fluorescent lamps, and are provided by SHS suppliers.
The wiring constituting of wire and cable is used for the connexion of different elements of SHS. From the PV generator to charge regulator the minimum acceptable cross-section is 2.5 mm2, from charge regulator to battery it’s 4 mm2 and from charge regulator to loads its value is 1.5 mm2.
The documentation is a handbook which provides instruction for users.

The photovoltaic pumping system

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PV Pumping system in Senegal
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PV Pumping system in Senegal (2)

The photovoltaic pumping system (PVP) is used for:
  • drinking water supply;
  • pumping for irrigation;
  • livestock watering.

The PVP equipment mainly comprises:
  • the PV generator generally constitutes one or more polycrystalline photovoltaic solar module;
  • the inverter which converts direct current (DC) into alternating current (AC)
  • the pumping system;
  • the tank for water storage.

Advantages

  • among the range of energy sources PV remains safer and cleaner;
  • SHS energy is free and autonomous;
  • PV is an adequate response for decentralised power source for landlocked areas;
  • PV produces no noise when it’s functioning.

Disadvantages

Solar photovoltaic cells are still two to five times as costly as power from the grid. Yet, the sale of solar photovoltaic cells expanded 42 per cent in 2002. If annual production grows by 25 per cent a year, solar capacity could reach 106,000 megawatts by 2020, generating as much as 30 to 40 large nuclear plants. Since 1980, the price of solar cells has fallen by 80 per cent.
  • its dependence to lights is a limit when energy storage is failure in night
  • good use of PV requires some advices from supplier;
  • solar home system (SHS) use is limited to cooling and refrigeration;
  • pumping, cooling and refrigeration are out of cost for poor people to meet their energy need.

SPV USERS

Some farmers from Tamil Nadu in South India, heard about the Solar Photovoltaic (SPV) water pumping system. It promised an end to the water problem in their fields and so they installed one such system. There's plenty of water now, and at a reasonable cost since solar photovoltaic water pump works out far cheaper than a diesel pumpset.

Sundarbans, the largest delta region, is one of the remotest areas of West Bengal, India. It constitutes of small river islands spread out over a large area and accessible only by waterways. The primary source of lighting is the use of kerosene lighting devices and torch lights, followed by limited use of diesel generator (DG) sets. A range Solar Photovoltaic (PV) systems were installed here for domestic lightening installed under the INDO-US project on Solar PV lighting system.

Ladakh is remote region located in the Himalayas with very low population density. Small scattered loads and good availability of renewable energy resources like hydro, solar, wind and geo-thermal, makes the region ideal for renewable energy based decentralised power generation. At present hydro and solar energy play an important role in power generation and rural electrification in Ladakh. Hydro-electricity from small, mini and micro hydro plants (installed capacity 8.5MW) accounts for about 60% of the total electricity generation. About 7000 solar PV domestic lighting systems (DLS) provides electricity for lighting to about 25% of the households in Ladakh. Solar DLS have proved to be a reliable source of electricity supply in remote villages of Ladakh.

Devices

  • solar-powered watch
  • solar water heater
  • solar powered calculaters
  • Solar Photovoltaic (SPV) water pumping system
  • solar PV domestic lighting systems (DLS)

  • Sundarbans: from Dhibris to solar photovoltaic. Sinha S, Mirza A, and Shukla A. 2000. In: Renewable Energy Technology for the New Millennium 373-379 pp, edited by R Banerjee, J K Nayak, and B G Fernandes New Delhi: Allied Publishers 507 pp.
  • Power generation from renewables in Ladakh: status and prospects.1999 Maithel S, Malhotra P, Prasad R, Singh D, Kumar A, Shukla A, Sinha S. In: Renewable Energies and Energy Efficiency for Sustainable Development: Proceedings of the 23rd National Energy Convention pp. 430-434, edited by R L Sawhney, D Buddhi, and R P Gautam Indore: Devi Ahilya Vishwavidyalaya 504 pp.
  • Abdelhanine Benallou and Michel Rodot – December 2002 – l’électricité solaire au service du developpement – second edition- 173 pages
  • FONDEM – 2003 – Guide de dimensionnement, d’installation et de maintenance de petits systèmes solaires photovoltaïque
  • FAO- 1997 – le rapport de l’atelier portant sur Guide technique sur l’intensification des cultures horticoles par l’application de l’exhaure solaire et de l’irrigation localisée - 245 pages
  • EDF – October 2002 – Electricity for all: targets, timetables, instruments – World Summit for sustainable development
  • Bart Van Campen and AL – 2000 – Solar photovoltaic for sustainable agriculture and rural development – FAO – 91 page
  • NJERI Wamukonya – 2001 – Experience with PV systems in Africa – UNEP – 86 page
  • GTZ – February 2000 – Photovoltaic systems in developing countries: Quality standards for solar home systems and rural health power supply

Contributors

User:Grant Ballard-Tremeer 1 September 2003
Dr Karabi Dutta 31 October 2003
User:Mamadou Fall 4 June 2007





Last edited by Miriam Hansen , based on work by Grant Ballard-Tremeer .
Page last modified on Tuesday 28 of September, 2010 11:27:53 GMT. @HEDON: MACB

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