Waste to Electrcity: Some Technical Solutions
The Indian economy faces significant challenges in terms of meeting its energy needs in coming decade. There is an increase in energy requirement but there is slower than expected increase in domestic fuel production. Thus, there has been increased importance of energy mix.
Coal continues to remain the dominant fuel in total production (65%). There is 75% electrification in India. This means, one-fourth of Indian population still lacks access to electricity.
 India is the first country to have a Ministry of non-conventional energy resources in early 1980s
 India’s cumulative grid interactive has reached 33.8GW. 66% is from wind energy and solar PV contributed nearly 4.59% along with biomass and small hydro projects.
Waste to Energy (WtE)
 Every year, 55mt of municipal solid waste and 38 billion litres of sewage are generated in urban areas.
 Waste generation is expected to increase rapidly in future at per capita rate of approx. 1-1.33% annually
 India has long involvement with anaerobic digestion and biogas technologies
 Waste water treatment plants have been established which produce renewable energy from sewage gas.
Types of waste
 Urban waste
 Industrial waste
 Biomass waste
 Biomedical waste
Importance of WtE
 Problems caused by solid and liquid waste can be mitigated by adoption of environment friendly waste to energy technologies that will allow treatment and processing of waste before their disposal.
 Environmental benefits will be less land, air and water pollution.
 It generates clean, reliable and renewable fuel source thus, reducing dependence on fossil fuels
 Monetary benefits- government incentives, right technology will enhance acceptability, more research in getting energy from sewage waste, industrial waste and hazardous waste. Expansion possibilities if they become successful
Energy from Waste-Technologies
> Involves thermal degradation of waste under high temperature
> Complete oxidation of waste occurs at high temperature
> Technology: Incineration
> But, it is losing attention because of emission characteristics
> Involves high temperature driven decomposition of organic matter to produce heat/energy/fuel/gas
> Useful for wastes that contain high percentage of organic non-biodegradable matter and low moisture content
> Technology: Pyrolysis and gasification
> The products of these processes can be used purely as heat energy or further processed chemically, to produce a range of end products
> Involves enzymatic decomposition of organic matter by microbial action to produce methane gas and alcohol etc.
> Used for wastes having high percentage of organic biodegradable matter high level moisture/water content
> Technology: Anaerobic digestion (biomethanation) and fermentation
> Refers to microbial fuel cells
> System is developed to trap energy from wastes where reduction-oxidation machinery of immobilised microbial cells is catalytically exploited for accelerated transfer of electrons from organic wastes to generate electricity and bio-hydrogen gas
 WtE still a new concept
 Most proven and commercial technologies are imported
 Cost of projects are high, especially projects like biomethanation which is exclusively imported
 Low level of compliance to MSW rules, thus, segregated solid waste is generally not available at plant sites.
 Lack of financial resources with urban bodies/municipal corporations
 Lack of conducive policy guidelines from central and state governments
Support of Indian government
 Recognised waste to energy as renewable technology and supports through varioussubsidies and incentives
 The Ministry of New and Renewable Energy actively promoting all technology options available for energy recovery from urban and industrial wastes
 Promoting research, providing financial support for R&D projects on cost-sharing basis. Key stats such as value of recyclables, amount of environmental pollution from waste resources and quantity of industrial waste generated need to be computed to gain better understanding.
 Solid waste management is as crucial component of Swachh Bharat Mission