A White Paper from. Energy Alternatives India

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Hilary Harmon
5 years ago
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1 A White Paper from Energy Alternatives India

2 Introduction The high volatility in fuel prices in the recent past and the resulting turbulence in energy markets has compelled many countries to look for alternate sources of energy, for both economic and environmental reasons. Every year there is an estimated 40 million tons of solid waste and 4,400 million cubic meters of liquid waste generated in the urban areas of India alone. Most wastes that are generated find their way into land and water bodies without proper treatment, causing severe pollution. They also emit greenhouse gases like methane and carbon dioxide. The problems caused by solid and liquid wastes can be significantly mitigated through the adoption of environment-friendly waste-to-energy technologies which hold the potential to create renewable energy from waste matter. These technologies hold the promise of reducing the quantity of wastes, generate a substantial quantity of energy from them, and greatly reduce pollution of water and air, thereby offering a number of social and economic benefits that cannot easily be quantified. This white paper attempts to provide the much needed guidance for planning and execution of projects in the niche waste to energy sector. The white paper was developed to provide a balanced opinion about the potential for energy generation from wastes and strategies for identifying suitable waste to energy solutions, thereby facilitating tangible steps for a waste to energy venture. Types of Waste and their Constituent Sources Types of waste Urban waste Agro-waste Industrial waste Biomedical waste MSW Sewage Solid Liquid Paper Sewage sludge Crop debris Brine mud Waste oil and oil emulsions Glass Livestock wastes Copper slag Tarry (Cattle, Pig, waste/heavy Poultry, Sheep metals Waste etc.) Metals Bagasse Paper and Pesticidal Laboratory pulp waste reagents Synthetic fibres Press mud Red mud Effluent dyes Discarded medicines Human anatomical wastes Animal waste and

3 cyto-toxic drugs Inerts Abbatoir waste Chromium Slurries Body fluids sludge Sand Lime sludge Volatile Surgical wares organics Leather Metallurgical Incineration ash slags Rags Gypsum Microbial cultures Pharmaceuticals Flyash Kitchen wastes Oil sludges Sanitary wares Effluent chemicals Textiles Mixed wastes Waste to Energy Technologies and Pathways Broadly, waste can be classified into solid waste, liquid waste and special waste. Solid, liquid and gaseous fuels can be generated from these wastes through diverse technologies. They can be used for various applications in power, transport and heating. Solid fuels refer to various types of solid material that are used as fuel to produce energy usually by the process of combustion or gasification. Solid fuels include briquettes, charcoal, pellets and solid recovered fuel (SRF). The most important liquid fuels include ethanol, biodiesel, bio oil, synfuels and other hydrocarbon biofuels. Gaseous fuel, apart from being used for power is also increasingly being used for transport and heating. Some of the gaseous fuels include biogas/methane, syngas/producer gas etc. There are a number of new and emerging technologies for producing energy from waste without direct combustion. While it is difficult to summarize all the technologies in a single flow diagram, we have attempted to compile the main categories and processes for wasteto-energy generation.

4 Pathways illustrating waste to energy technologies (Source: EAI Waste to Energy Research)

5 Technological Options for Waste to Energy Combustion/Incineration In the modern waste management industry, combustion is the mere burning of waste without the recovery of energy or materials. As such, combustion / incineration is increasingly being banned in OECD countries due to environmental impacts. There are a number of other new and emerging technologies that are able to produce energy from waste without burning the waste directly. These technologies are considered to generate renewable energy and are widely perceived to be more acceptable than incineration. Landfill with Gas Recovery These systems have been widely used in developing countries for over two decades having overcome the concerns associated with atmospheric emissions and leachates, now that there are adequate controls in place. The present emphasis is on material recovery facilities with limited land availability for new LFG facilities in the urban centers and the fast filling up of the sites currently in use. This would require only a limited quantity of recalcitrant waste to be sent to landfills as a repository. Gasification Gasification is the process of partial incineration with restricted air supply to create an air-deficient environment, can be used to convert biomass and plastic wastes into synthesis gas with a heating value 10-15% that of natural gas. When integrated with electricity production it can prove economically and environmentally attractive, though it appears better suited for clean biomass wastes. The synthesis gas in turn can be converted to methanol, synthetic gasoline, or used directly as a natural gas substitute and even blended with it in a gas supply line. Pyrolysis Pyrolysis / Thermal Depolymerization is the chemical decomposition of waste by heating in the absence of oxygen or any other reagents, except possibly steam. It is another option for waste to energy that is being investigated. Pilot projects using pyrolysis for plastic wastes, and for mixed municipal solid waste potentially have demonstrated very highenergy efficiencies. This technology is increasingly moving towards commercial scale.

6 Refuse Derived Fuel (RDF) Using raw unprocessed MSW as a fuel is problematic due to the heterogeneous nature of the material, which varies according to region and season. It also has a low heat value and high ash and moisture content. This makes it difficult for plant designers and operators to always provide acceptable pollution free levels of combustion. Processing of the waste to refuse derived fuel (RDF) partially overcomes these problems. Waste with high organic (carbon) content is suitable for briquetting and pelletizing after noncombustible and recyclable materials have been separated. These processes involve the compaction of the waste at high temperatures and very high pressures. Plasma Arc Waste Disposal Plasma arc gasification is a method of waste management that uses high electrical energy and high temperature created by an electrical arc to break down waste materials primarily into elemental gas and solid waste. Anaerobic Digestion (Biomethanation) Anaerobic digestion takes place where the waste has restricted aeration, such as in the later stages of the decomposition of municipal solid waste (MSW) or in the digestion of sludge or wastewater in enclosed digestion vessels. Anaerobic digestion produces methane and water, and also some carbon dioxide and hydrogen sulphide. The gas produced by anaerobic digestion can therefore be combusted and used, either to produce electricity or heat, thereby converting the methane gas to carbon dioxide Hydrolysis and Fermentation Organic wastes can be converted to ethanol, the alcohol found in beverages, through bacterial fermentation (enzymes may be used to speed up the process), which converts carbohydrates in the feedstock to cellulosic ethanol. Feedstocks predominantly used, include forestry and agricultural wastes, such as molasses or waste starch, with more recent developments focusing on municipal organics, including food and sewage sludge.

7 Analysis of Key Challenges and Benefits for Waste to Energy Technologies Critertia Incineration Anaerobic Digestion Gasification/Pyrolysis A Feedstock Nature of waste Industrial Liquid Not suitable Suitable Not suitable Solid Suitable Not suitable Suitable Urban Liquid Not suitable Suitable Not suitable Solid Suitable Suitable Suitable Farm Poultry Suitable Suitable Suitable Cattle Suitable Suitable Suitable B Technology features Technology status Industrial Proven proven Emerging Urban Proven Proven Emerging Farm Proven Proven Proven Energy efficiency 85-90%(Based on 50-60%(Based on 90-95%(Based on calorific value) volatiles) calorific value) C Operating conditions System Complex Simple Complex configuration Process Low Good Low Flexibility Modular Yes Yes Yes D Capital, O & M costs Relative capital Very high Medium Very High cost O & M High Low Limited Commercial Less viable Readily viable Varies considerably viability Captive power Signifgicant Low Variable Area requirements Elaborate Compact Compact E Environmental Costly Minimum Amenable for impacts additional costs F Socio-economic impacts Public Satisfactory Satisfactory Satisfactory acceptability Waste disposal Complete, except for ash to landfill. Complete except for sludge stabilization Complete, except for ash Source: MNRE (

8 Main Products from Different Waste to Energy Technologies Gasification Pyrolysis Incineration Biomethanation Fermentation Heat Hydrogen Heat and Biogas Alcohols Electricity Olefins electricity (Methane) (Ethanol, Hydrogen, Speciality Thermal Propanol, Alcohols chemicals Power Butanol) FT Gasoline Oils Soil nutrients Organic acids FT Diesel Phenols Esters Oleffins Aromatics Enzymes Oxochemicals Methane Microbial Ethanoic acid Biochar biomass DME Pigments Methyl esters Polysachharides Ethanol Probiotics Propanol Anti-oxidants Methanol and flavoured Diesel compounds etc. Naphtha and Lubes (Fischer- Tropsch process). Source: EAI Waste to Energy Research

9 Summary The business of Waste to Energy is primed to enter a period of rapid growth in India. The dual needs of waste management and reliable renewable energy source is having a multiplier effect and has created attractive opportunities for investors and project developers. Early movers who have identified the right technologies are already poised to grow with this promising industry. However, the yet to be commercialized technologies, a tight credit market and an evolving regulatory environment present significant industry challenges. There are some unanswered questions with respect to the viability of waste to energy projects. The complexity of navigating through these bottlenecks, calls for a clear understanding of the business case behind various wastes to energy solutions. Given the need for critical knowledge on the viability of waste to energy projects before venturing into this niche sector, assistance from an advisory and research firm such as ours is imperative. EAI has been researching the waste to energy sector for the past few years and we have developed an exhaustive understanding of the various technology options for waste to energy. We have worked with prestigious clients like Bill & Melinda Gates Foundation (USA) for waste to energy projects and can offer actionable market intelligence and consulting services for the waste to energy sector.

10 About EAI is the foremost research and consulting company for the Indian renewable energy industry We have a dedicated focus on the Indian renewable energy sector. We are unique in our focus on market and strategy research for renewable energy. Our team has assisted businesses large and small on a variety of renewable energy projects. Our expertise has been sought by Fortune 100 companies. Our team comprises professionals from premier institutes such as the IITs and IIMs. The cumulative wisdom of our team, derived from extensive research and hands on consulting, has provided us with deep insights about the industry which few, if any, have. Energy Alternatives India Madhavan Nampoothiri madhavanv@eai.in

GASIFICATION THE WASTE-TO-ENERGY SOLUTION SYNGAS WASTE STEAM CONSUMER PRODUCTS TRANSPORTATION FUELS HYDROGEN FOR OIL REFINING FERTILIZERS CHEMICALS

GASIFICATION THE WASTE-TO-ENERGY SOLUTION WASTE SYNGAS STEAM CONSUMER PRODUCTS HYDROGEN FOR OIL REFINING TRANSPORTATION FUELS CHEMICALS FERTILIZERS POWER SUBSTITUTE NATURAL GAS W W W. G A S I F I C A T