Introduction-02

Key Concepts

• Waste to energy (WTE) conversion
• Sustainability (economic viability, environmental bearability, social equity)
• Municipal Solid Waste (MSW)
• Inert reduction in MSW
• Energy demand and supply gap
• Waste to energy technologies (incineration, gasification, pyrolysis, anaerobic digestion, fermentation, chemical methods, physical roots)
• Thermal vs. biological conversion routes
• Microbial Fuel Cell (MFC)
• Policy and regulatory framework for energy production

Need for Energy Production from Waste

• Double Benefit: WTE conversion addresses both energy demand and systematic solid waste management, contributing to sustainability goals.
• Sustainability: WTE helps achieve sustainability by being economically viable (energy supply, job creation), environmentally bearable (reduced health hazards, pollution control), and socially equitable (job opportunities for all genders).
• Health Hazards: Improper waste management leads to air, water, and soil pollution, clogged drainage, greenhouse gas emissions, and health problems (infections).
• Increasing Waste Generation: Statistics show a rise in per capita urban MSW generation across low, middle, and high-income countries, emphasizing the need for effective waste management solutions. For example, waste generation in middle income countries is expected to increase from 0.52-1.1 kg per day in 1999 to 0.8-1.5 kg per day in 2025.
• Energy Potential of MSW: Indian cities have significant potential for electricity production from MSW. For instance, the average MSW generation capacity in 59 Indian cities is 81,407 tons per day, with the potential to produce 1292 MW of electricity.
• Reduction of Inerts: The inert component in MSW is decreasing with economic development, making it more suitable for energy conversion. Compostables increased from 40% in 1973 to over 50% in 2005, while inerts decreased from 48% to below 30% in the same period.
• Energy Demand-Supply Gap: In India, 237 million people (19% of the population) lack access to electricity, highlighting the need for alternative energy sources like WTE.

Energy from Waste: World and Indian Scenario

• Global WTE Market: WTE technologies convert MSW into heat, electricity, and fuel through complex conversion methods. Companies like Foster Wheeler, ABB, and China Everbright are commercializing these technologies.
• European Scenario: In the EU27, over 400 incineration-based WTE plants process approximately 22% of total municipal waste. In 2014, 88 million tons of waste were incinerated, generating 88 billion kWh of heat and 38 billion kWh of electricity, supplying 15 million and 17 million inhabitants, respectively. This saved 9 to 48 million tons of fissile fuels.
• UK Scenario: WTE plants like Willingham 1 and 2 are active in the UK, with capacities of 360,960 and 291,840 tons per annum, producing 29.2 MW and 21.0 MW of power, respectively. Belfast RDF plant generates both electricity and heat (cogeneration).
• China Scenario: Active WTE plants in China, such as Feng Yang, have capacities of 560,000, 76,000, and 479,232 tons per annum, producing 12, 30, and 14.8 MW of power, respectively. Some plants utilize cogeneration.
• Indian Scenario: As of March 31, 2014, India had a total installed capacity of 245,259 MW, with renewable energy contributing 31,692 MW (13%). The country has a renewable energy potential of 147,615 MW but utilizes only 21% of it.
• Renewable Energy Potential in India: Wind energy has the highest potential (70%), followed by small hydro (13%), biomass (12%), and waste (2%). Cogeneration using bagasse accounts for 3%. Biomass and waste contributed 4,120 MW of electricity in 2014, representing 13% of total renewable energy.
• Policy Framework: Various ministries and organizations, including central and state governments, the Ministry of External Affairs, the Ministry of Environment, Forest and Climate Change, the Ministry of Railways, the Ministry of Shipping, the Ministry of Road Transport and Highways, and NITI Aayog, are involved in formulating energy policies.

Routes for Energy Production from Waste

• Thermal Roots:
  • Incineration: Burns waste to produce hot flue gas, generating electricity, steam, or heat.
  • Gasification: Converts waste into syngas, which can be used to produce electricity, chemicals, or hydrogen.
  • Pyrolysis: Decomposes waste into bio-oil, char, and gas.
• Biological Conversion Roots:
  • Anaerobic Digestion: Decomposes organic matter in the absence of oxygen to produce methane-rich biogas.
  • Fermentation: Uses microorganisms or enzymes to convert waste into alcohol, acids, etc.
• Chemical Methods:
  • Hydrolysis: Breaks down complex organic compounds into simpler acids.
  • Transesterification: Converts waste cooking oil or algal bio-oil into biodiesel.
  • Solvent Extraction: Extracts bio-oil from oilseeds.
• Physical Roots:
  • Briquetting: Densifies solid waste into uniform, high-strength briquettes.
  • Distillation: Separates products.
  • Mechanical Extraction: Extracts bio-oil.
• Comparison of Thermal and Biological Routes:
  • Thermal: Applicable to almost any biomass feedstock, higher productivity, multiple high-value products, unaffected by ambient temperature, mostly complete biomass utilization.
  • Biological: Applicable to selected feedstocks, slower productivity, product-specific, susceptible to ambient temperature, incomplete biomass conversion (sludge production).
• Liquid Waste Treatment:
  • Anaerobic digestion is suitable for waste with high COD (Chemical Oxygen Demand) values.
  • Microbial Fuel Cells (MFCs) are used for waste with lower COD values.

Risks of Waste to Energy Conversion

• Technology Maturity: Many WTE technologies are not fully matured.
• Residual Disposal: All processes generate residue that requires proper disposal mechanisms.
• Environmental Regulations: Meeting increasingly strict environmental norms is a challenge.
• Economic Feasibility: The economic viability of WTE processes, especially newer technologies, is uncertain due to the relatively low energy content of waste. However, the cost of alternative waste management methods should be considered.

Synthesis/Conclusion

The video emphasizes the growing need for WTE conversion as a sustainable solution to address increasing waste generation and energy demand. It highlights the potential of WTE technologies, provides global and Indian scenarios, and discusses various conversion routes. While challenges remain regarding technology maturity, environmental regulations, and economic feasibility, the video concludes that WTE conversion is a promising approach for managing solid waste and generating energy, especially considering the costs associated with traditional waste management methods.