The Langmuir Approach to Rural Development

This article is due to be published in Current Science Journal.

To read this artcle in detail click here(pdf link)


In this article, Dr. Anil K. Rajvanshi, Director of Nimbkar Agricultural Research Institute (NARI)
Phaltan-415523, Maharashtra, India has discussed that historically, technology development for rural areas has followed tinkering approach or use of rudimentary technology. But it has been shown that very sophisticated science and technology is needed for producing devices for rural applications and that in this process very fundamental research can also result. Nevertheless availability of excellent devices for cooking, lighting and water purification on large scale in rural areas is a bottleneck. He has outlined various strategies on how to overcome this barrier. A strong case is made for closer cooperation between civil society and corporate world for rural development.In this article, he discusses how developing devices for rural applications can lead to fundamental research of highest order and also explores a possible strategy for their mass dissemination in rural areas.

The author has suggested the Langmuir Approach to Rural Development. Irving Langmuir-the U.S. chemist who was the first industrial chemist to receive the Nobel Prize showed that in the process of doing applied research one can be led to do fundamental research of highest order. Thus in developing a better incandescent light bulb for General Electric (GE), Langmuir discovered atomic hydrogen and laid the foundation of surface science for which he received the Nobel Prize in Chemistry in 1932. A similar thing could be possible in doing research for rural development.The author tries to show in this article how developing devices for rural applications can lead to fundamental research of highest order and will also explore a possible strategy for their mass dissemination in rural areas.

Although sophisticated technology can touch every aspect of rural life , the author restricts himself in this paper to three basic areas of lighting, cooking and clean drinking water. These examples nevertheless can be extended to include other areas like agriculture, power generation etc.

A short summary of this article is presented below:

Lighting Energy Strategy

In many rural areas, there is no power due to unavailability of electric grid so there is a need to develop decentralized lighting sources and devices. These devices should be based on locally available renewable fuels. Thus renewables like solar energy, ethanol or biodiesel can power decentralized lighting devices.


1.High efficiency solar cellscan be made.

  • Existing solar cells produce one electron-hole pair per photon.
  • Classic photoelectric effect of Einstein.
  • Process of impact ionization allows conversion of single high-energy photons to multiple electron-hole pairs.
  • Nano sized quantum dots of materials PbSc and PbS have demonstrated high efficiencies in multiple electron-hole pair generation 5.
  • As many as 3 electron-hole pairs production possible per photon in these materials thereby creating 50% and above solar cell efficiencies.

2.Liquid fuel lighting can be done in two ways- firstly through thermoluminescent mantle lighting and secondly through the use of a prime mover running on renewable fuels, which produces electricity and hence light. However in both these schemes the most important resource is affordable renewable liquid fuel. Very fundamental researches are being done in biotechnology so as to increase the yields of fuel crops; to engineer organisms to increase the yield of ethanol from plant sugars and to find chemical pathways for conversion of sugars into useful automotive fuels. There are also indications that sugar either in solid or in solution form can be directly used as fuel in engines.

3.High-efficiency light emitting diode (LED) lanterns are some of the other micro-technologies being developed to produce power in the range of 10-20 W. All these devices are being developed to be powered by renewable fuels like ethanol, methanol, methane, hydrogen, etc.Such small devices used for lighting will eliminate the heavy and environmentally unfriendly batteries, since the storage of energy is in fuel itself.

4. Bioluminescence -This is a fantastic and the most efficient natural lighting systems where the chemical energy is directly converted into light.If in future a system can be adopted to develop devices based on this mechanism it could revolutionize decentralized lighting in rural areas.A truly fantastic idea.

Cooking Energy Strategy

Only liquid and gaseous fuels produced renewably can provide clean cooking energy. Three fuels fall into this category. Liquid fuels like ethanol or biodiesel, and gaseous fuels like biogas.


1.Ethanol is an excellent fuel for cooking. NARI has developed a stove which runs on 50% ethanol-water mixture. The stove has a maximum thermal capacity of 2.5-3 kW and has a flame control for simmer and high settings, so that it works just like an LPG stove.16 Large-scale testing in the field has been positive and almost all the rural women who have tried it compare it favorably with an LPG stove. However, in order that such low grade ethanol can be used as a rural household fuel, the presently tough excise laws have to be modified.

2.Biogas is a clean gaseous fuel that can be produced from the existing biomass sources. However there are problems of gas production during winter due to low temperature and improper mixing of mixed inputs like biomass, night soil, cowdung, etc.These are the technological shortcomings preventing its large scale adoption. Also biogas, which is a mixture of methane and carbon dioxide, cannot be liquefied and requires high pressure of more than 100 atmospheres to compress it so that it can be used over extended periods.

These shortcomings in biogas can be removed by doing R&D in two areas.
  • One is in the development of extremely efficient biogas reactors, so that the production per unit of biomass inputs could be maximized. Very efficient and sophisticated biogas reactors are being developed and deployed in Europe and USA with an installed capacity of about 6000 MW. Also in Sweden biogas is being used in substantial way to run automobiles and public transport system.
  • The second is to develop appropriate storage materials which could store biogas at medium pressures. Research is also in progress in methane storage and recently experiments have been conducted in storing it at medium pressures of less than 30 atmospheres in hydrates and porous carbon and organic structures.18 Thus there is a need to develop low-cost storage materials so that biogas could be stored in them for usage in households. New materials developed through nanoscience and nanotechnology can be used for this purpose.

Clean Drinking Water

Waterborne diseases are one of the greatest scourges in rural areas. According to WHO estimates approximately 1.8 million people die every year worldwide, because of unavailability of clean drinking water in these areas. Too often the focus of development agencies has been on providing simple water cleaning technologies for individual rural households. These have included solar stills, hand powered RO units, simple filters etc. Most of the times these devices do not work, with the result that these households keep on using contaminated water.


The author believes that the rural households should be supplied clean drinking water just like that in any urban household. Thus public/private water utilities should be set up in rural areas to harvest rain water in specially dug tanks, clean and purify the stored water and supply it either through rural pipe networks or allow the inhabitants to take it in their own utensils as they do presently from existing supply. Hence R&D and new policy framework is required for developing small water utilities in rural areas.

The author also offers some new ideas in areas of water purification research which can be investigated like trying to duplicate the reverse osmosis process of mangroves and other types of plants.

Availability Of Devices in Rural Areas

In past good amount of R&D in India and in other developing countries has been done in developing efficient devices for rural areas. Somehow they have not become available at affordable price and on large scale. Part of the reason is

  • lack of purchasing power in the rural areas and
  • partly because of shortcomings in technology.

Recently with the availability of micro-finance and proliferation of rural self-help groups, a substantial section of rural population worldwide can afford to buy devices for household purposes.

For example the large scale proliferation of cell phones in rural areas of India attest to the fact that the availability of a very good technology at affordable price is the first step in overcoming financial hindrances. Similarly in Bangladesh large scale usage of cell phones in rural areas is made possible by micro-finance instruments from Grameen Bank.

The author feels the “industrial model” of cell phones should be followed in producing devices for rural areas. The industrial model means large scale production of goods and devices based on excellent technology, reasonably priced with excellent availability of after sales service.


1.Developing good and robust technology. Most of the rural devices have failed because of half baked technologies. Whether it is PV systems (lead acid battery failures); biogas systems (materials or gas delivery system failures) or improved chulhas (hardly reduced smoke). Contrast this with robust and good technology devices like electronic watches, cell phones, motorized two wheelers, etc which have shown excellent sales in rural India.

2.Creating corporate interest in developing and manufacturing these devices. Somehow the basic rural amenities are not in the vision field of corporate world since most of their efforts are in urban areas. For example cell phones percolated from urban to rural areas and so have other technologies. One of the reasons could be that the captains of the corporate world are not aware of the rural problems.Thus sensitizing them to the problems the author feels will go a long way in this regard.

3.Corporate Social Responsibility (CSR) is a buzzword which is now becoming popular in western countries. Hence more and more international corporations are financing activities world over which will help the rural poor. In India the multinational companies (MNCs) have taken the lead too. CSR allows for the first time a window of opportunity for corporate world to take part in rural development. Nevertheless most of the corporate world is not involved in CSR as a charity. They see tremendous economic returns to their investments both directly in selling devices and indirectly through creation of goodwill. In India rural development by corporate world can be a lucrative business. For example there are estimates that cooking and lighting industry in rural India, based on liquid fuels like ethanol, could be of the order of Rs. 30-40,000 crores per year.

Finally the author points out all the technological development for devices and products in western countries follow the Langmuir model. Thus the basic research is either done in-house in the industry ( e.g the development of the Philips wood stove) or there is a strong industry-university partnership (e.g The Urja stove developed by BP was in partnership with IISc, Bangalore, India). It is necessary that this model should be extended to rural areas of India and other developing world. The problems of rural areas are different from those in urban areas and their solutions have also to be different. In trying to solve these problems both the industry and academia will also benefit greatly in monetary and intellectual terms.
  1. “Langmuir, the man and the scientist”, in Collected Works of Irving Langmuir (Ed. C. Guy Suits), Vol. 12, 1962. Pergamon Press.
  2. Padma, T. V. “Village India: untouched by science boom”,, 15 May 2006. here.
  3. Rajvanshi, A. K., “Energy for the rural poor – challenge for the global community”, Current Science, Vol. 93, No. 5, 10 September 2007.
  4. Intermediate Technology Development Group (ITDG), “Smoke - the killer in kitchen”, here.
  5. “Basic Research Needs for Solar Energy Utilization”, Workshop report, Office of Science, USDOE, Washington D.C. April 18-21, 2005, pg. 91. here
  6. Burke, Andrew, “Ultracapacitors: why, how and where is the technology?”, 2000, here
  7. Pushparaj, V. L. et. al., “Flexible energy storage devices based on nanocomposite paper”, PNAS, Vol. 104, No. 34, 13574-77, August 21, 2007.
  8. Ragauskas, A. J. et. al., “The path forward for bio fuels and biomaterials”, Science, Vol. 311, 27 January 2006, pp. 484-489.
  9. Y. Roman-Loshkov,, “Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates” Nature, Vol. 447, No. 7147, 21 June 2007, pg. 982-985.
  10. “University of Kansas researchers add a dose of sugar to diesel fuel”, Science Blog, 2004. here.
  11. Rajvanshi, A. K., “R&D strategy for lighting and cooking energy for rural households”, Current Science, Vol. 85, No. 4, 25 August 2003.
  12. Rajvanshi, A. K., “Ethanol lantern for rural areas”, unpublished report to DST, New Delhi, November 2007.
  13. Venkatasubramania, R., et. al., “Thin film thermoelectric devices with high room temperature figures of merit”, Nature, 2001, 413, 597-602.
  14. Efficient micro fuel cells,
  15. Wilson, E., Light sticks, Chem. Engg. News, 1999, 77, 65.
  16. Rajvanshi, A. K., “Low concentration ethanol stove for rural areas of India”, Energy Sustain. Dev. 2007, XI, 94-99.
  17. Persson, M., “Biogas upgrading and utilization as vehicle fuel”, Proceedings Future of Biogas in Europe-III, 14-16 June 2007, University of Southern Denmark, Edberg, Denmark. here(pdf link).
  18. Sanderson, K., “Space invaders”, Nature, Vol. 448, No. 7155, 16 August 2007, pg. 746-748.
  19. WHO data on contaminated water, 2007. here
  20. Rajvanshi, A. K., “Strategy for rural electrification”, REPSO-VISION, Winrock International, New Delhi, Jan.-March 2006, Vol. 33.
  21. Scholander, P. F., “How Mangroves Desalinate Seawater”, Physiologia Plantarum, Vol. 21, 1968, pp. 251-61.
  22. Grameen Telecom Case Study. [|here.


Last edited by Miriam Hansen , based on work by Grant Ballard-Tremeer .
Page last modified on Friday 22 of October, 2010 11:49:57 GMT. @HEDON: YTKB

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