From the Indian Copper Belts to Chulhas: Affordable Thermoelectric Materials for Rural India

Lead Research Organisation: University of Reading
Department Name: Chemistry

Abstract

An estimated 840 million people in India use a solid-fuel cookstove (chulha) powered off wood or biomass. These are very inefficient and produce emissions harmful to health and the environment. Chulhas emit harmful pollutants and particulates that contribute to respiratory diseases, including chronic obstructive pulmonary disease and lung cancer. India has the largest number of people exposed to high levels of indoor air pollution (IAP), which is primarily caused by solid-fuel cookstoves. IAP was responsible for 482,000 deaths in India in 2017 alone, the largest number of deaths attributable to IAP worldwide. The cooking stoves operate at temperatures up to 600 deg. C, providing a ready supply of waste heat. A thermoelectric (TE) device is capable of converting this waste heat into useful electricity, providing a localised power source to power an auxiliary fan to improve combustion in the stove, making them cleaner, safer and more efficient and mitigating the effects of IAP.

Approximately 100 million people in rural areas of India have no access to electricity. The areas which electrification has not reached are among the more remote, where off-grid electricity generation is essential. A TE device would also provide sufficient electrical power to fulfill basic needs in lighting, communication and mobile device charging. Addition of a TE device to a chulha would therefore provide a cleaner cooking environment whilst simultaneously delivering a localised electricity supply delivering a major impact on the health and well-being of rural communities.

Central to the creation of a TE generator for use with a cooking stove is the development of materials that are affordable, sustainable and optimised to the working temperature (< 600 deg. C) of the stove. Proof of principle has been demonstrated with commercially-available bismuth telluride modules. However tellurium is scarce and bismuth telluride and the corresponding modules expensive. In this project we seek to develop materials that meet the criteria of performance and cost that are optimised for use in the traditional cooking stoves. In particular, we will create new sulphide TE materials for electricity generation that are derived from minerals such as chalcopyrite, bornite and chalcocite, to which India has access to potentially cheap and abundant reserves in the Indian copper belts, including the Khetri, Singhbuhum, and Malanjkhand copper belts. In this way the project seeks to apply the natural resources of India to the solution of a problem affecting a substantial number of the most disadvantaged sector of the population.

The project will benefit from the combined computational and experimental expertise of three leading TE laboratories in the UK and India. By applying a variety of materials design strategies and synthetic approaches, we seek to create new high performance n- and p-type semiconductors that can be incorporated into a TE device for electrical power generation in the temperature range 200 < T/deg. C < 400, using the waste heat from a cooking stove.

Planned Impact

The use of a thermoelectric-powered fan to provide more complete combustion in the cookstove will have a positive impact on the health of the rural population through reductions in the emission of harmful pollutants and particulates. This is a particularly acute problem in India, where in 2017 60% of the population (846 million people) still cooked using traditional solid-fuel stoves. In 2017 alone, there were 1.2 million deaths in India attributable to air pollution, which causes a variety of chronic non-communicable diseases including chronic obstructive pulmonary disease and lung cancer; of these ca. 0.5 million deaths were attributed to indoor air pollution. Exposure to indoor air pollution arising from solid-fuel combustion is particularly high among women and young children under the age of five, who spend more time near the stove. Two thirds of the illnesses caused by indoor air pollution occur in women and children. Therefore the project would have a disproportionately positive impact on the female population.

The 100 million people in rural India who do not have access to a distributed electricity supply will benefit from the novel thermoelectric materials developed in this project for use in the temperature range 200 < T/deg. C < 400. These materials will provide the capability to generate electricity from heat produced by burning solid fuels in cooking stoves, providing an off-grid source of electrical power to supply basic needs.

We also foresee an impact through the training element of the project, which will support research capacity building by increasing the skills and knowledge base in the area of advanced materials that supports economic development. There will also be an impact on the researchers themselves, employed through the project, as they will acquire new high-level scientific and technical skills that will have a major impact on their future careers. This in turn will have an impact on wider society as these trained individuals will contribute to the further development of knowledge-led societies in India and the UK.

Although the project is fundamental in scope, there is also the opportunity for a longer term economic impact as the materials to be developed are derived from copper sulphide minerals, of which the Khetri, Singhbuhum, and Malanjkhand copper belts in India have a rich supply. Successful development of routes to make the most effective and direct use of the raw minerals would therefore have an impact on Hindustan Copper Ltd, the principal operator of mines in this region.

Although focused on the needs of the rural population of India, there would be secondary impact on the wider global community of TE researchers in academia and industry. In particular, demonstration of the effectiveness of compositing with two-dimensional inorganic nanosheets and advances in understanding the relationship between microstructure and transport across interfaces, have the potential to lead to new design paradigms and underpin future developments across a wide range of TE materials and devices.

Publications

10 25 50
 
Description Although COVID-19 led to a delay in the start of this project, collaboration with JNCASR, India has already been successfully established and exchange of expertise has commenced. Initial investigations have identified promising candidates for materials that can be used in thermoelectric devices to deliver the proposed environmental and health benefits to the population of rural India. Detailed exploration of the materials is underway in the UK and India. Recruitment of Indian nationals to two of the three research positions in the UK, offers added benefits in Knowledge Exchange.
The project has led to new materials that can form the basis of new cheaper thermoelectrics capable of providing a secondary source of power in rural India. At this stage of the project, we have engineered the thermoelectric properties of the cheap mineral chalcopyrite (abundant in India) to achieve a reasonably high figure of merit (zT = 0.35). If translated into a device coupled with the p-type materials currently being optimized, this performance would offer electricity generation at 10 -20 cents per Watt, based on raw materials costs (excluding manufacturing costs). The principal application of the materials that have been developed is in traditional domestic cookstoves (Chulhas), where they will use the heat of the Chulha to generate electricity. This will power a fan that will improve the combustion process and hence reduce indoor pollution: a major cause of respiratory diseases. In this way the project will make an important contribution to the health and welfare of the population in rural India. Although the creation of a thermoelectric generator was not an objective of the project, device design and construction, based on materials emerging from the project derived from cheap mineral feedstocks, offers potential for significant economic development in India through device manufacture.
The project has led to contact being established with the Indian Government's Geological Survey of India, which will help identify appropriate mineral resources and inform their effective use in a future device. Samples of relevant minerals have been secured and their thermoelectric properties are being evaluated.
The project has resulted in progress towards the development of novel low-temperature synthetic processes for chalcogenide thermoelectrics. This is a key step in any future exploitation as the solution and mechanochemical-based processes developed in the project, are more easily scale-able and less energy intensive than traditional high-temperature methodologies in controlled atmospheres.
The collaboration between theoreticians at the University of Reading and the JNCASR as part of this project has also led to the development of new computer simulation protocols, based on the combination of density functional theory predictions and machine learning models, for the simulation and prediction of electrical and heat transport properties of these materials. This will be important to rationalise the experimental findings in the project and to aid the selection of the most promising routes to engineer the thermoelectric properties of the mineral-based materials.
Exploitation Route COVID-19 related restrictions have imposed limitations on the ability to meet directly with stakeholders and to carry out reciprocal visits of research personnel. A database of charities working in India has been compiled and the project has joined the Clean Cooking Alliance (https://cleancooking.org/sector-directory/university-of-reading-department-of-chemistry/). Efforts are being made to establish contact with the mining companies through The Geological Survey of India, with which contact has been established. When travel restrictions are lifted, the priority will be the organization of a workshop with representatives of charities, industrialists, policy makers and NGOs. This workshop will be used to identify barriers to adoption of the technology within rural and disadvantaged communities, to formulate an initial design of the energy harvesting device and to determine routes to implementation of the research that optimize the impact on living conditions and health.
Sectors Energy,Environment,Manufacturing, including Industrial Biotechology

 
Description Training of Indian scientists: This project has resulted in the training of young Indian scientists for the research of energy materials that can have a significant impact in the economy of India in the near future. This includes the two postdocs recruited at JNCASR (Dr Meghna Manae, Dr Animesh Bhui) and the two postdocs recruited at the UoR (Dr Sahil Tippireddy and Dr Vikram); they are all young Indian researchers. The extra funding received from EPSRC to nurture this International Partnership (not associated to this project but a result of it), has led to further training of other young Indian researchers (Dr Matukumilli Prasad and Dr Shivani Grover) in energy materials research. As a result of this project, these Indian researchers have had access to high-end research facilities that are not available in India, including the Diamond Light Source and the UK Tier 1 and Tier 2 High-Performance Computing facilities.
First Year Of Impact 2020
Sector Energy,Environment
Impact Types Societal

 
Description Institutional Sponsorship-International Partnerships-University of Reading
Amount £45,464 (GBP)
Funding ID EP/W524268/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2021 
End 03/2022
 
Description RETF Continuation Funding
Amount £24,400 (GBP)
Organisation University of Reading 
Sector Academic/University
Country United Kingdom
Start 03/2022 
End 09/2022
 
Description JNCASR, Bangalore, Inida 
Organisation JNCASR Jawaharlal Nehru Centre for Advanced Scientific Research
Country India 
Sector Academic/University 
PI Contribution Formulating the original project, securing funding and supporting collaborators with funding and expertise. Regular review meetings to discuss progress. Training session to Indian team on using new software package to calculate lattice thermal conductivities.
Collaborator Contribution Alternative synthesis methods for target materials, particularly low-temperature approaches such as solvothermal methods. Measurement of additional materials properties, using equipment to which we would not otherwise have access. Complementary computational investigations of transport properties across interfaces. Liaison with the national Geological Society in India to secure native mineral samples relevant to the project.
Impact One publication to date. Visit planned. Further funding received to support collaboration: has supported on-going visit by Indian researchers to Reading.
Start Year 2020
 
Description #RSCPoster Twitter Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Dr Vikram presented a poster with title "Thermoelectric behaviour of CuFeS2 from DFT simulations" at the RSC annual poster conference on Twitter.
Year(s) Of Engagement Activity 2022
URL https://twitter.com/hashtag/RSCPoster?src=hashtag_click
 
Description EPSRC Thermoelectric Network UK Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was an online meeting, which took place on 17th November 2021, and included international participants working on the field of thermoelectrics. Dr Sahil Tippiredy delivered a talk on "Improvement of Thermoelectric Performance of CuFeS2 Chalcopyrite via Ge Substitution"
Year(s) Of Engagement Activity 2021
 
Description Royal Society of Chemistry's Solid State Group Christmas Meeting 2021 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Dr Vikram delivered a talk entitled "Thermoelectric behaviour of CuFeS2 from DFT simulations" to the Royal Society of Chemistry's Solid State Group Christmas Meeting, December 2021.
Year(s) Of Engagement Activity 2021
URL https://sites.google.com/view/sscg40/schedule
 
Description Society of Chemical Industry (SCI) Materials for Energy Technology Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Dr Sahil Tipirredy delivered an online talk, entitled "Enhanced Thermoelectric Performance in Cr Substituted CuFeS2 Chalcopyrite" to an audience included industrialists and researchers interested in materials for energy applications.
Year(s) Of Engagement Activity 2021
 
Description Virtual International Conference on Thermoelectrics 2021 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Dr Sahil Tippireddy delivered an online talk entitled "Improvement of Thermoelectric Performance of CuFeS2 Chalcopyrite via Sn Substitution" to an international audience.
Year(s) Of Engagement Activity 2021