Converting Waste Agricultural Biomass into Useful Energy Surya

Converting Waste Agricultural Biomass into Useful Energy Surya Prakash Chandak Senior Programme Officer International Environmental Technology Centre Division of Technology, Industry, and Economics United Nations Environment Programme (UNEP DTIE IETC) HP: www. unep. org, www. unep. fr, www. unep. or. jp 1 International Environmental Technology Centre UNEP

What is biomass Broad term generally refers to any plant or animal matter. Waste Biomass – Main Categories • • • 2 Waste agricultural biomass Forestry residues Wood Animal residues Organic waste from cities and dwellings International Environmental Technology Centre UNEP

Why convert waste agricultural biomass into energy/materials ? • • • 3 Reduced carbon emission a) Due to obviating use of fossil fuels b) Due to avoidance of open burning and rotting (methane emission) Enhanced energy security Enhanced access to energy particularly in rural areas Reduced problem of management, treatment and disposal Additional revenue for farmers Job creation International Environmental Technology Centre UNEP

Global availability of waste agricultural biomass (in EJ/year) Region Maize Straw Wheat Straw Rice Straw Bagasse TOTAL Africa 0. 48 0. 25 0. 20 0. 54 1. 47 US & Canada 2. 95 1. 93 0. 19 5. 20 Latin America 0. 71 0. 38 0. 29 3. 58 4. 94 Asia 1. 74 3. 65 8. 96 3. 19 17. 54 Europe 0. 61 2. 39 0. 04 0. 00 3. 04 Oceania 0. 23 2. 26 0. 06 0. 22 2. 77 TOTAL 6. 72 10. 86 9. 68 7. 72 31. 98 (765 million tons oil 1 Exa joule = 1018 Joules : 1 Kilo. Joule = 0. 239 Kcals: 1 EJ = 24 million tons oil (approx. ) 4 International Environmental Technology Centre UNEP

Geographic distribution of availability of waste agricultural biomass (in percent of total) Region Maize* Wheat** Rice Cotton Sugar# Total China 8 6 15 3 2 33 India 3 3 8 1 3 18 All Asia 13 13 39 5 6 77 Brazil 2 0 1 1 4 8 All South America 5 1 1 1 5 13 Africa 5 1 1 9 TOTAL of Asia, S. America and Africa 23 15 41 7 12 100 *including millet and sorghum **including barley #including minor agro industry 5 International Environmental Technology Centre UNEP

Technologies for converting waste agricultural biomass into energy Waste Agricultural Biomass to Energy – Technology Options Basic Process Type of Technology Fermentation Examples of types of waste handled Biochemical (aerobic) Fermentation Sugar/starch containing wastes like waste palm trees Thermochemical Pyrolysis Crop residues such as wheat straw, rice husk, coconut shell Thermochemical Gasification Crop residues such as wheat straw, rice husk, coconut shell Thermochemical Direct Combustion Crop residues such as wheat straw, rice husk, coconut shell Physical Processing Briquetting Waste saw dust, waste wood chips Biochemical (anaerobic) 6 Fruit and vegetable market waste, waste from fruit/vegetable processing industries International Environmental Technology Centre UNEP

Interesting features of converting waste agricultural biomass into energy • Availability of energy source at the place which is energystarved and conventional energy (electricity and fossil fuels) systems are difficult to reach there • Abundant availability -- a large amount is currently wasted by either burning open or by allowing it to rot in the field • Little or no pollution; generally no emissions of toxic gases like sulfur oxides and nitrogen oxides • Provides a clean fuel for both domestic and commercial use – current patterns of using WAB directly in households usually gives rise to emission of smoke and gases which are very harmful to human health • Can provide and alternative source of income to farmers • Can spur rural economic development due to enhanced energy availability thus generating jobs • Climate neutral 7 International Environmental Technology Centre UNEP

Constraints in converting waste agricultural biomass into energy • Dispersed availability spread over wide areas hence challenges of collection • Usually voluminous material hence high transportation cost per unit weight – compacting prior to transportation may be required • Lower calorific value as compared to fossil fuels particularly oil and gas • Some WAB has high moisture content (e. g. fruit and vegetable waste) • Some WAB is easily putrescible (e. g. fruit and vegetable waste) • Seasonal availability and variations • Matching of demand supply of energy – energy load in rural areas varies widely over the day 8 International Environmental Technology Centre UNEP

Features for considerations when converting waste agricultural biomass into energy • Systems required for collection and compacting • Considerations for future costs of WAB although it may be available free at present • Considerations for alternatives if WAB is being used for some other purposes presently e. g. as domestic fuel, animal feed, mulching for soil etc. • Cost of transportation in case of large size WAB 2 E systems • Disposal of ash particularly for WAB like rice husk • Flexibility in WAB 2 E systems to use different WAB • Storage of WAB to meet the needs during lean seasons • WAB 2 E systems to have high turn down ratios and/or systems to store energy 9 International Environmental Technology Centre UNEP

What needs to be done for converting waste agricultural biomass into energy 10 • Assessment of WAB quantities generated and quantity available for conversion into energy – careful consideration of seasonal variations • Characterization of WAB • Study of possible systems for collection, compaction and transportation • Assessment of present cost structure and projections into future, including cost of transportation • Assessment of present energy demand (type and amount) and projections into future • Assessment of funds availability • Assessment and selection of WAB 2 E technology • Development of a management system for sustainable operations • Supportive policy framework International Environmental Technology Centre UNEP

What this project on converting waste agricultural biomass into energy aims at • • • 11 Building capacity on various aspects of WAB 2 E: assessment of quantification and characterization, assessment of prevailing management systems, assessment and selection of technologies Provide hands-on experience by working at a selected site Demonstration of an appropriate technology which can be further replicated Getting together technology suppliers and entrepreneurs to facilitate commercial uptake of WAB 2 E systems Support to government on framing conducive policies International Environmental Technology Centre UNEP

THANK YOU For further information: http: //www. unep. org 12 International Environmental Technology Centre UNEP