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Biomass-based Gasifier for Sustainable Rural Energy in India

Pierre Jaboyedoff1, Ulrik Birk Henriksen2, Jesper Ahrenfedt3, Sunil Dhingra4, Mohit Pushp5

1 Sorane SA, Rationalisation Energétique, Ecublens, Switzerland2 Technical University of Denmark (DTU), Risoe National Laboratory for Sustainable Energy, Denmark3 Technical University of Denmark (DTU), Risoe National Laboratory for Sustainable Energy, Denmark4 The Energy and Resource Institute, New Delhi, India5 The Energy and Resource Institute, New Delhi, India

Presenting author’s email address: pierre.jaboyedoff@sorane.chAbstract Record Number: 315Presentation Theme (Theme 1, Theme 2, Theme 3): Theme 1

Key Words: rural energy, off-grid electricity generation, biomass, gasification, India

Brief biography of presenting author (80 words):

Pierre Jaboyedoff is a senior engineer specialising in energy efficient buildings and solar energy applications withover 30 years’ experience in the field. While representing the Swiss Federal Office for Energy, he participated inmany major Research and Development projects lead by the International Energy Agency. He has developed theenergy concept for low-energy buildings such as the Rolex Learning Centre or the Swiss National Office forStatistics. He has been working in India on energy efficiency since the early 80s.

Abstract (max 320 words):

Half of India’s rural households have no access to electricity. In 2005, more than 96,000 villages were still un-electrified, and just over 40% of the 138 million households used electricity for lighting. Rural electrification is akey concern for India’s social and economic development. Besides, rural electrification in remote areas posesconsiderable challenges in terms of technological applications, investment costs and paying-off potential, as theconnection to the grid is found to be complex and costly, while the loads required are rather limited. For suchareas, small-decentralised biomass gasification based power plants emerge as an attractive option for ruralelectrification provided biomass is managed locally in a sustainable manner.

During the last 3 decades, small-scale power gasifiers have been tested in many regions of the world. More recentdevelopments have demonstrated the feasibility of 100% gas systems, but the technology has not yet reached acommercial level. Meanwhile, DTU has developed an innovative two-stage biomass gasification process, which ischaracterised by having pyrolysis and gasification in separate reactors with an intermediate tar cracking zone. Thisallows for a fine control of the process temperatures resulting in extremely low tar concentrations in the raw andproduced gas.

Based on a broad partnership involving the Swiss Agency for Development and Cooperation (SDC), the Energyand Resources Institute (TERI) in India, the Indian NGO Gram Vikar, the National Thermal Power Corporation(NTPC), Sorane SA and the Technical University of Denmark (DTU), an initiative was launched to apply thetechnology to India for rural off-grid power production. Small-scale applications will range between 10 to 50 kWe.The technology developed will allow remote communities to operate the system with minimal scheduledmaintenance, while making use of local material and human resources.

This project has the potential to facilitate the introduction of sustainable and reliable biomass based powergeneration in villages, which will allow for increased social and economic benefits for the remote rural populationof India.

Paper

Introduction and purpose

With almost half of its rural households having no access to electricity, rural electrification is a key concern forIndia. In 2005, more than 96,000 villages were still un-electrified, and just over 40% of the 138 million householdsused electricity for lighting. The economics of remote rural electrification based on grid-extension are generallyunfavorable, mainly because of the high costs incurred by grid extension, the important grid losses in such remote

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areas, as well as the small loads required and the low tariffs applicable. Out of these un-electrified villages, theGovernment of India has identified 25,000 villages as remote and difficult to access. For these un-electrifiablevillages which stand out of the scope of grid-connected electrification, decentralized power generation systems arebetter suited. Electricity needs of these villages are generally in the range of 5 to 25 kW depending upon their size.It has been proposed that these villages should be electrified through renewable energy sources (e.g. biomass,small hydro, solar PV etc.). Among various renewable energy sources solar PV is technically mature but the initialcosts are very high. Small hydro systems are comparatively cheaper, but these are site specific and the powergenerating capacity fluctuates seasonally. In this scenario, small-decentralised biomass gasification based powerplants emerge as an attractive option for rural electrification provided biomass could be managed locally in asustainable manner.

The figure above presents the concepts of livelihood for remote biomass-based electrified villages. This conceptwas developed by Joe Madiath, executive director of the renowned Indian NGO Gram Vikas, located in Orissa.

At the time when this concept was developed, the technology for 100% biomass-based power gasification was stillquite new. Most of the existing systems had very complex gas cleaning systems. Most of the technologydevelopers focused on end-of-the-pipe gas cleaning treatment.

Meanwhile, the Technical University of Denmark (DTU), has developed an innovative two-stage gasificationprocess, which allows for biomass-based small-scale power generation.

Based on a broad partnership involving the Swiss Agency for Development and Cooperation (SDC), the Energyand Resources Institute (TERI) in India, the Indian NGO Gram Vikar, the National Thermal Power Corporation(NTPC), Sorane SA and the Technical University of Denmark (DTU), an initiative was launched to apply thetechnology to India for rural off-grid power production. The main objective of the project funded by SDC is toadapt the DTU technology for a small-scale 100% woodgas power gasifier, suitable for remote rural electrificationin India. Small-scale applications will range between 10 to 50 kWe. The technology developed will allow remotecommunities to operate the system with minimal scheduled maintenance, while making use of local material andhuman resources.

Figure 1: LIBERA framework diagram(The first framework was developed by Joe Madiath and Pierre Jaboyedoff)

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Design and Methods

During the last 3 decades, small-scale power gasifiers have been tested in many regions of the world. More recentdevelopments have demonstrated the feasibility of 100% gas systems, but the technology has not yet reached acommercial level. Conventional systems consist of a gasifier, a gas cooling and cleaning system and an internalcombustion engine. Most of the development has been focusing on the gas cleaning to avoid high tarconcentrations.

Figure 2: Typical gasifier and gas cleaning arrangement in the early 2000' (Kishore 2006)

When installed in villages, most of these systems had very serious operational problems. Starting the engine wasvery difficult, and tar condensation at various places of the cleaning system occurred very frequently. Thedevelopment of the technology was advanced and its needs well framed, but its actual implementation was veryproblematic due to its technical complexity and difficult operation.

Sorane SA is a consulting engineering company created in 1977 in Lausanne, specialised in energy efficiency inbuildings as well as renewable energy applications. Sorane has worked on energy efficiency and renewable energyin India since the 80s.

The Technical University of Denmark (DTU), is ranked as one of the foremost technical universities in Europe. Itcontinues to set new records in the number of publications, in the development of new partnerships with industryand in its public sector consultancy assignments. For almost two centuries DTU has been dedicated to developingand creating value using scientific research to benefit society.

The Energy and Resource Institute (TERI), is a renowned research organisation established in 1974 in view ofsupporting sustainable use of resources. TERI is a non-governmental organisation, that carries out research andconsultancy on renewable energies and energy efficiency with a view of contributing to poverty alleviation andsustainable development. In 1998, TERI created its own university.

The NGO Gram Vikas was established by student volunteers, who came to Orissa, as part of the Young Students'Movement for Development (YSMD), Chennai, in the early 70s to help the victims of the cyclone. Gram Vikascurrently serves over 350000 people in villages spread over 24 districts in Orissa.

NTPC, the National Thermal Power Corporation is the largest power generating major in India, with an installedcapacity of 36,014 MW. It has also diversified into hydro power, coal mining, power equipment manufacturing, oil& gas exploration, power trading & distribution. With an increasing presence in the power value chain, NTPC iswell on its way to becoming an “Integrated Power Major”. NTPC is a key partner of the Government of India inimplementation of the National Strategy for Renewable Energy Development in the country.

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The Swiss Agency for Development and Cooperation (SDC) is Switzerland’s international cooperation agencywithin the Federal Department of Foreign Affairs (FDFA). The Agency engages in direct operations, supportsprogrammes of multilateral organisations, and helps to finance programmes run by Swiss and international relieforganizations in four operational areas. SDC has been active in India since 1963 with development cooperationprogrammes and humanitarian aid interventions designed to improve the living conditions of the poor andmarginalised segments of the population and to contribute to sustainable development. Since 1992, as part of itsglobal environmental programme, SDC India has contributed to India’s efforts in dealing with globalenvironmental problems anchored in national concerns by implementing projects to i) facilitate technologytransfer, ii) train workers to maintain new technologies, iii) develop, demonstrate and disseminate energy efficientand environmentally friendly technologies in the energy intensive small scale industries. Considering the fastgrowing importance of India as a key player on the regional and international scene, Switzerland has engaged in anew type of collaboration in areas of common interest. Today, Swiss Cooperation programmes are focused onclimate mitigation and adaptation and are managed by the recently created Climate Change Division (CCD) in theEmbassy of Switzerland to India.

Facing the challenge of developing an adapted technology for off-grid biomass-based rural electrification, Soraneassisted TERI in identifying technological partners able to bring in technologies of gasification practically withouttar. After a comprehensive review of the sector’s developments, Sorane SA established a contact with DTU. Afirst mission was then organised to launch a collaboration between DTU, TERI with Sorane being the consultantfor system integration.

After analysing and recognising the problems of tar in the existing gasifiers in India, it was decided to have a firstfield test with a charcoal-based gasifier. Charcoal as a fuel presents the advantage of containing very little tar, as itis removed by pyrolysis during the process of charcoal preparation. A first cooperation agreement was establishedbetween SDC, TERI and DTU. DTU assisted in the design of this charcoal system, following which the gasifierwas installed in a village near the head office of the NGO Gram Vikas in Orissa.

Figure 1: the 10 kWe charcoal gasifier installed at Kanheiput, Orissa (Kishore, 2006)

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Figure 2: View of the filter before the engine after 200 hours of operation

The system was operated daily for more than 3000 hours with minimal level of maintenance. The technologicalapplication and field experience demonstrated that it was possible to run small-scale power gasifiers, provided thetar level in the gas remains very low.

Over the last 15 years, DTU has developed an innovative two-stage biomass gasification process, which has beendemonstrated on a pilot plant with fully automatic operation for more than 3000 hours. The two-stage process ischaracterised by having pyrolysis and gasification in separate reactors with an intermediate tar cracking zone. Thisallows for a fine control of the process temperatures resulting in extremely low tar concentrations in the raw andproduced gas. Measured performance levels are 20% to 30%, from biomass to electricity. The main aim of theresearch lead by DTU was to develop a fully automatic and unmanned operation plant.

The main advantage of this technology is that the biomass is first heated up to about 600°C, which provokespyrolysis reactions. After that, the pyrolysis gases and the biomass enter the reactor. This technology allows toproduce gas practically without any tar.

Figure 3: Schematic principle of the Viking Gasifier

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Figure 4: A view of the Viking gasifier developed and tested by DTU

The Viking two-stage gasifier developed by the biomass gasification group of the Technical University ofDenmark (DTU), has been tested in automatic operation for over 3000 hours. The reliability and performance wereexcellent. The gasifier efficiency was over 90%, the overall electrical efficiency at 25%, the tar level below 1mg/Nm3.The main advantage of this technology is the simplicity of the gas cleaning.

Applications for remote rural use in India would not require such sophisticated automatic control mechanisms,because local employment generation is a priority in areas where poverty alleviation is a primary concern.

Sorane SA assisted TERI and DTU to get funding to make the technology transfer and its adaptation to Indianconditions possible. After unsuccessful attempts with the World Bank, SDC eventually accepted to fund the TERI-DTU partnership.

Within the current project framework, the conceptual design of the wood-based gasifiers and the systemconfiguration will be developed, following which a prototype will be created and then tested for optimisation. Thepartnership with the National Thermal Power Corporation will help to formulate a long term strategy fortechnology up-gradation and implementation of Renewable Energy and Distributed Generation.

Results

The prototype has been successfully developed and is now adapted for application in the framework of ruralelectrification in India. The results achieved through this testing are summarized below:

The two stage biomass gasifier system, along with the cleaning and cooling system, has beentested with engine on a 10 kWe load.

Cumulative operation: 195 h including 95 h of engine operation High quality gas: Tar <25 mg/m3; CV > 4 MJ/kg with H2 and CO content in the range of 22-

24% and 15-18 % respectively Low specific fuel consumption: around 1 kg/kWh Elimination of the LPG for preheating which is being carried out by thermal gasifiers for both

reactor and pyrolysis unit Simple dry time cooling cleaning system developed No waste water generation in cleaning and cooling system Optimization of parasitic load to reduce them and improve the net output from the system

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Experimentation on the existing system for further improvement with use of the waste heatstreams and trial of different feed stocks

Following the success of this first phase, the detailed design of the second generation (20 kWe) has been finalizedand the fabrication is now under progress. After testing and validation at TERI, it will be packaged and transferredto NTPC for system fabrication and installation at their premise. NTCP will then test it under variable loadconditions, and produce and install 4 pilot units in villages.

After this phase, the system will be reengineered for a power of 40 kWe and will be disseminated in unlectrifiedvillages where biomass supply is secured and managed in a sustainable way. This technology will be part of IndianNTPC’s renewable energy generation strategy.

This project has the potential to facilitate the introduction of sustainable and reliable biomass based powergeneration in villages. The two stage process developed by DTU and TERI jointly brings a much simpler and morereliable technology with better performances than the conventional end-of-the-pipe treatment systems usedtraditionally.

Thanks to the adaptation of this innovative technology, rural electrification of some of India’s villages will beachieved in a sustainable way.

Conclusion

The SDC-funded biomass gasifier project is an example of technological applications that take into account socialand economic needs as well as environmental concerns. The technological development is directly geared atproviding energy, comfort and a better working environment to India’s remote rural population. As shown by theLIBERA Diagram, the two stage biomass based gasification technology for rural electrification has the potential toprovide means for irrigation, enhancing food security, enabling domestic access to water and lighting as well asopportunities for additional monetary resources.

Reference List

Henriksen, U and alt. (2006) The design, construction and operation of a 75 kW two-stage gasifier, Energy,Volume 31, Issues 10–11, August 2006, Pages 1542–1553

Kishore, VVN (2006) Biomass and gasification success stories and lessons learned, IEA Bioenergy Agreement,Task 33, Fall 2006 meeting at GTI

Jaboyedoff, Pierre (2010) 100% Woodgas based 100% Woodgas based small scale power gasifier for addedincome generation in biomass-rich non grid connected areas, Summary of activities in India between SDC,TERI and DTU (internal report for SDC Head Offices, Bern)

Dhingra, Sunil (2012) Biomass gasification project at TERI, DSDS 2012 (Delhi Sustainable DevelopmentSummit), Special event on « Moving towards alternative energy for addressing rural energy needs »