The idea of a ‘solar revolution’ – whereby we will all use free electricity from the sun, which is the biggest source of renewable energy on the planet – has an alluring ring to it and the hope that it will come true someday has become stronger over time. At this point, the possibilities are limitless – on a bright, sunny day, the sun’s rays emit approximately 1,000 watts of energy per square metre of the planet’s surface. All our homes and offices can be powered for free if only this energy were to be harnessed.

So, how do we get up to using the sun’s energy on a daily basis? And how do we make the process of converting the sun’s energy directly into electricity cost-effective?

Solar means green and free
First, let’s understand the process. The solar cells that one sees on calculators and satellites are also called photovoltaic (PV) cells, which, as the name implies (photo = ‘light’ and voltaic = ‘electricity’), convert sunlight directly into electricity. Calculators with solar cells never need batteries – so long as there is light, they work. A module is a group of cells connected electrically and packaged into a frame (commonly known as a solar panel), which can then be grouped into solar arrays. Solar panels can be seen on emergency road signs and buoys, and even in parking lots to power the lights.

PV cells are made of semiconductors such as silicon. When light strikes the cell, the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, which then flow freely. PV cells also have one or more electric field that acts to force these free-flowing electrons to travel in a certain direction. This flow of electrons is a current, and by placing metal contacts on the top and bottom of the PV cell, this current can be drawn for external use.

Solar lamps are funky and functional
The most important point: Solar power does not use fossil fuels, a nonrenewable energy source. As the environmental consequences of industrialization and unbridled consumerism start to become visible and pose a very real threat to the long-term well-being of our precious planet, ensuring a sustainable future becomes each individual’s responsibility and commitment. As they say, it is now or never. ‘Carbon footprint’ cannot remain an aloof term any longer and we cannot but be aware of the energy we use each day. Additionally, as the price of fossil fuels and other nonrenewable energy sources keeps moving up, consumers are anyway being forced to think about other sources of energy.

In rural areas and remote locations where electricity from conventional sources is not available—and in some cases remain beyond the purchasing capability of households—solar lanterns are widely used. They are an obvious viable alternative to kerosene lamps and candles.

A solar lantern consists of a photovoltaic (solar) panel, a high-efficiency compact fluorescent lamp (CFL) or LED light, a rechargeable battery, and a charge control circuit. When exposed to light during daytime, the solar energy is converted by the solar cells to electrical energy and stored in the batteries. The charge control circuit prevents the batteries from getting overcharged. A single charge is enough to operate the lamp for at least 4 hours to 5 hours.

Expectedly, the performance of the battery will keep getting upgraded as the technology is further fine-tuned. Already, Austa’s solar lamp claims to be providing nearly 8 hours of running time with a single charge. The lamp has LEDs that give out light 360 degrees, which means that there are no dark corners in the room. This is the reason why the lamp can be useful even in city homes. Today, many urban households anyway use CFLs because of their energy-saving benefits. CFLs can save up to 40 per cent electricity, but in most cases one CFL is not enough for a whole room. Most households end up using multiple CFLs in each room, in a way compromising the electricity saving benefits.

The CFL lamp usually works for 3 years to 4 years. The sealed lead acid gel battery is designed to work for several charging and discharging cycles. Some lanterns are designed to be charged from mains electricity using an AC adapter. Austa’s solar lamp is one such. Further, the portable lamp is so designed as to be shielded against dust and water sprays. The PV cells are encapsulated within weather-proof packaging. The solar panel can be kept outside during rainy weather as well. All of these features make the product nearly maintenance-free—all that is required is the occasional wiping of the solar panel to keep it free from dust, dirt, and debris, to allow the battery to charge properly.

Solar impact
The market for lights in India is massive—500 million Indians live in villages. Based on data given out by the power ministry, there were 105,379 un-electrified villages as on 30 June 2008. There is more to the story and the numbers, though. The Planning Commission describes a village as ‘electrified’ if even a percentage of its residents have power supply. Thus, if one house in 10 is electrified, the village is considered powered. That leaves nine unlit homes—all potential customers of solar.

The stated objective of the Indian government’s Remote Village Electrification (RVE) programme is to electrify all the remote census villages and remote hamlets of electrified census villages through non-conventional energy sources such as solar energy, small hydro power, biomass, wind energy, hybrid systems, etc. Under the programme, the ministry of new and renewable energy (MNRE) provides central financial assistance (CFA) of up to 90 per cent of the total cost for solar PV home lighting (subject to a maximum of Rs 11,250 per household) and street lighting system.

With limited grid access in most parts of rural India, decentralized off-grid solar and other non-conventional applications provide a promising—and perhaps the only workable—solution to immediately meet the lighting needs of rural households. Rising energy demand, mandate for remote rural lighting and electrification, increasing emphasis on clean technologies to combat greenhouse gas (GHG) emissions, increasing policy support, and decreasing costs of solar electricity will provide the impetus to ensure that off-grid solar applications grab a larger market share in the near future.

Moreover, positioned against polluting and potentially hazardous kerosene lamps, solar off-grid lighting applications are set to become economically viable in the near future. As per National Sample Survey Organisation (NSSO) 2008, about 39 per cent of households in rural India still use kerosene to meet their lighting requirements. Kerosene lamps generally provide poor-quality light, produce greenhouse gas emissions, and have significant health and safety hazards associated with their use.

Solar-powered lights represent a clean and completely functional substitute to kerosene and other nonrenewable energy sources, both for domestic and commercial lighting in rural areas. Lighting solutions using solar technology can be as simple as a solar lantern or complete solar home lighting systems. A solar lantern containing a small fluorescent or LED light with a rechargeable battery is an energy upgrade for kerosene lamp users. A solar home system that can power light bulbs and basic electrical appliances such as cell phones and small televisions score still higher on the energy ladder.

While the solar lanterns involve a much higher upfront cost as compared to kerosene lanterns, they present significant advantages. A comparison between the two is illustrated here.

Comparison of solar and kerosene lanterns

Characteristic	Kerosene lantern	Solar lantern
Capital cost	Low	High
Cost of fuel	Depends on usage	Nil
Replacement cost	Low (replaceable items being glass chimney, cotton wick)	High (replaceable items being CFL, battery)
Availability and reparability	Very good even in remote locations	Poor due to limited sale and servicing outlets
Lumen output	Low	4- 5 times higher
Flexibility of illumination Safety aspects	Possible by lowering the wick Fire and health hazards due to smoke	Easy adjustability (from 0% to 100%) Safe to use
Portability   Subsidy burden	Transportation hassles due to inflammability of kerosene   Recurring burden of fuel	Portable, light in weight   One-time burden of capital subsidy (if provided)

Source: Chaurey, A. and T.C. Kandpal, ‘Solar lanterns for domestic lighting in India: Viability of central charging station model’. Energy Policy (2009).

With the prices of solar products trending downwards throughout the developing world, and with payment solutions such as small loans becoming available to meet the costs of upfront investment, the off-grid market is being viewed as a great business opportunity in an overall market worth billions of dollars. With more and more solar companies bringing energy to underserved populations, both parties stand to gain handsomely.

Note: Austa solar lights manufacturers are looking for special partnerships with corporate groups to align their CSR initiatives as well as collaborations with NGOs. Interested organizations may write to Harish Mehta at kharishmehta.nimh@gmail.com; vpmarketing@nimhmail.com

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