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About 500 million people in India's geography still have no access to electricity. The government's ruthless plan to electrify the entire nation by 2012 is based, in large part, on providing rural homes (particularly some 25,000 of the farthest villages) with decentralized renewable energy systems. Such decentralized renewable energy systems will include local energy generation and dissemination systems and will therefore be different from the large national or regional grid system followed elsewhere.
Having no access to electricity, rural areas use kerosene lamps at night for indoor lighting and for undertaking urgent family tasks outside the home. These kerosene lamps and lanterns use the heavily subsidized kerosene. These being some of the most polluting energy sources and the majority of rural homes being poorly ventilated, use of kerosene lamps poses an increased health hazard, causing respiratory and eye problems. In addition, inhalation of the fumes affects the longevity of women involved in many of the household chores. The use of kerosene lamps is also a threat to safety. Lamps can set fires in rural homes which are largely made of straw and mud. The light of these kerosene lamps, which are the open wick type (commonly used in rural India), provide low lighting intensity, far below that is required to meet reading needs adequately. Thus education suffers as well.
Solar power has proved to be very successful in replacing Kerosene lamps and providing basic necessity of life, electricity, to people. Solar energy, today, has become an effective and environmentally sustainable source of light. Use of solar power has scores of advantages. It averts the health hazards of kerosene lighting, which is alleged to be the reason for hundreds of deaths in India. Being decentralized, the solar energy systems offer a level of reliability and control that grid electricity throughout India does not Rural solar home lighting: The technological options
Rural solar home lighting systems have seen a lot of technological innovations in recent times. Much of this has been a result of the support this sector has been receiving, i.e. positive policy environment. Many of these innovations have looked at the suitability and the affordability issues of the rural population. The high energy efficiency of newer lighting technologies which have come up recently, like the compact florescent (CFL) and light emitting diode (LED), has revolutionized solar energy products. These innovations are so energy efficient that effective lighting capacity can be achieved from the energy generated from a small, solar photovoltaic (PV) panel. Some modifications have also been made in the battery which is needed to store the solar energy captured during the day, to enable emitting of light at night. The rural solar lighting system which the market currently offers has taken on a variety of forms like:
(1) Home lighting systems: This consists of a complete installed unit, namely a solar PV panel, a battery, a few meters of wiring, and lighting bulbs.
(2) Lanterns: This also requires almost the same equipment. But here the battery unit and the lighting bulbs are together, and can be taken to various locations once they are charged.
(3) Community centre or school lighting systems: Almost similar to the home lighting systems, except the fact that here the system is larger in size to generate more power.
Solar Home System (SHS)
Depending on the size, an SHS can operate one or several lights. Normally a SHS will have a 12-volt direct-current (DC) stand-alone system which uses PV to electrify small rural homes. Each SHS comes along with a PV module (also called Panel), a battery, a charge controller, wiring, fluorescent CFL lights, and outlets for other appliances. A typical design component is shown below:
It is important that those involved in choosing this system understand the different components. An elaboration of each of them is given below:
Solar modules for an SHS would range between 20-50 Wp. They are mounted on a rooftop or atop a pole. The technology of this could be either crystalline or thin-film technology12 (also called amorphous).
An electro-chemical storage battery is used to store the electricity converted by the solar module. During the day, electricity from the module charges the storage battery. During the evening, the battery is discharged to power the lights and other applications. Batteries are typically the 12-volt lead-acid batteries, ranging in capacity from 5-75 Amp-Hours (Ah). Batteries are typically sized to provide several days of electricity or 'autonomy', in the event of overcast weather preventing recharging.
A charge controller is utilized to control the flow of electricity between the module, the battery and the loads. It prevents battery damage by ensuring that the battery is operating within its normal charge levels. If the charge level in the battery falls below a certain level, a 'low voltage disconnect' (LVD) will cut the current to the loads, to prevent further discharge. Likewise, it will also cut the current from the module in case of overcharging. Of course, some systems do not have this facility. Those which do not have the automatic charge controller would use indicator lights on the controller to display the relative state of charge of the battery. This is seen in most of the models available in the market. This device is important as once overused, it takes a long time for the battery to get charged. In rural areas, where literacy levels are relatively lower, the presence of this device built into the system help prevent overuse of the battery, thereby increasing the life of the system.
Compact fluorescent light bulbs, fluorescent tube (off late) are used for lighting. An SHS normally would have anything between two-light systems to a four-light system. A 9 watt CFL provides illumination equivalent to a 60 watt incandescent bulb. These compact fluorescent lights have a 5-year lifetime.
Wiring & Mounting devices
An SHS will also have additional materials for mounting and connections. Metal frames are included to attach the PV Modules to a pole or roof. The SHS components are connected by wires and contain switches for the lights. In some cases, wiring is housed inside conduits attached to interior walls. These are important considerations as damages to wires by rats in rural areas can considerably reduce the life of the system. Similarly, the high velocity of the desert wind can destabilize the PV modules if not clamped well on the roofs. These two considerations are likely to be understood by those involved in installing the system. The technology as regards the solar panel, the battery and the bulbs is constantly being developed. The focus of the development is three-fold: a. Efficiency of the system, b. Cost reduction and
b. Rough and tough to suit to the conditions of the rural areas. c. Rough and tough to suit to the conditions of the rural areas.
Benefits of the Solar Home Light system
The benefits derived from the use of solar lamps have improved the overall well-being of the households. This has been observed during interaction with the users at the field locations. Some of the benefits are listed below:
1. A dive towards children's education: Most parents met during the field visits mentioned that the reading habit of the children had increased. They study during the evening hours. This is especially true for those villages which have regular teachers at the village school.
2. Improvement in health: With the solar systems in place, fewer women will tend to suffer from respiratory problems. Kerosene fumes will cease to affect the eyes of the family members. Winters being cold, the houses are kept shut all the time, and the kerosene lamp emits so much carbon that not only do the eyes burn, but also respiratory problems develop. Women are affected much more severely than men since they stay at home for much longer hours. The summer season is prone to gusty storms which can result in fire. Houses getting gutted during summers are a common phenomenon. With the solar system in place, these two ills have been taken care of to an extent.
3. Saving of money: In several houses, the supply of kerosene, which is normally 3-5 litres a month, comes from the ration shop. This consumption has stopped entirely or reduced drastically, helping the family save an average of INR 50 a month. The savings can go up to INR 100 for families which do not have access to subsidized kerosene supplies (which is also quite erratic in the area). This is over and above the hardships one has to face to go all the way to the ration shop which is normally about 3-4 km from the village, only
to find that the shop is closed or that kerosene is not in supply. 4. The other monetary benefit is the saving of money households spend on charging the mobile. This amounts to a savings of another INR 100 a month. Again, the benefit is also non-monetary as it is handy to charge the same from solar light when needed, rather than banking on someone going to the main market about 15-20 km away for charging it.
5. Increasing safety for the family: The benefits go much beyond financial calculations. For example, the light helps one to see that there are no stray insects in the food while eating, that no scorpions and snakes are around etc. These are benefits which are directly linked to the lives of the family members. Also, the light enables young mothers to nurture their infants at night and also help women working on manual flour mills. These are examples of benefits experienced by women. The safety which the Dayan (midwife) feels with the solar light on during delivery of a child at home .