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
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?
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.
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.
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
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
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
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.
of solar and kerosene lanterns
Cost of fuel
Depends on usage
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
4- 5 times higher
Flexibility of illumination
Possible by lowering the wick
Fire and health hazards due to smoke
Easy adjustability (from 0% to 100%)
Safe to use
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.
Austa solar lights manufacturers are looking for special partnerships with corporate
groups to align their CSR initiatives as well as collaborations with NGOs.