From UPSC perspective, the following things are important :
Prelims level : Refuse-derived fuel (RDF)
Mains level : MSW management
The new plant at Bidadi has several advantages but also some operational challenges.
Practice Question: Discuss the various benefits of waste to energy plants and challenges in running them successfully.
The prospectus of new plant
- The new 5 MW waste-to-energy plant is going to set up near Bidadi, Karnataka.
- This plant is expected to process 600 tonnes per day of inorganic waste.
- The inorganic waste, which consists of bad quality plastics and used cloth pieces, can be processed as Refuse Derived Fuel (RDF). This material has a calorific value of more than 2,500 kJ/kg.
- This can be used to generate steam energy, which can be converted into electric energy.
A well-planned plant
- The waste-to-energy plants usually accept the RDF material generated in organic composting plants.
- They also segregate the wet and inorganic material near the plant, convert organic waste to compost, and inorganic waste to energy.
- About 50 tonnes of RDF generate 1 MW of power, which indicates that the plant at Bidadi has been appropriately designed.
A permanent solution
- Handling inorganic waste that is not fit for recycling has always been a challenge.
- At present, these high-calorific materials are landfilled or left unhandled in waste plants and cause fire accidents.
- Attempts to send this material to cement kilns have not fructified.
- The proposed plant can source 600 tonnes per day of this RDF and generate 11.5 MW of power equivalent to 2.4 lakh units of power per day.
- This will reduce the dependence on unscientific landfills, reduce fire accidents, and provide a permanent solution to recover value from inorganic waste.
- Needed a good demonstration model – Over the last decade, several Indian cities have been trying to set up such plants but a good demonstration model is yet to be established.
- Nature of waste – Technology suppliers are international organizations who struggle with the change in quality and nature of waste generated in Indian cities. A few plants in India have stopped operations for this reason.
- The plants require fine inorganic material with less than 5% moisture and less than 5% silt and soil contents, whereas the moisture and inert content in the mixed waste generated is more than 15%-20%.
- The sticky silt and soil particles can also reduce the calorific value.
- Economic cost per unit of electricity – The other big challenge for this plant is the power tariff which is around ₹7-8 KwH which is higher than the ₹3-4 per KwH generated through coal and other means.
- For the successful running, the plant needs to ease the challenge of handling inorganic waste, the efficiency of organic waste processing/ composting plants.
- With the increasing waste generation in the coming years, there is a need for more such plants which are environment friendly.
Back2Basics: Refuse-derived fuel (RDF)
- Refuse-derived fuel (RDF) is a fuel produced from various types of waste such as municipal solid waste (MSW), industrial waste or commercial waste.
- It is selected waste and by-products with recoverable calorific value can be used as fuels in a cement kiln, replacing a portion of conventional fossil fuels, like coal, if they meet strict specifications.
- Sometimes they can only be used after pre-processing to provide ‘tailor-made’ fuels for the cement process.
- RDF consists largely of combustible components of such waste, as non-recyclable plastics (not including PVC), paper cardboard, labels, and other corrugated materials.
- These fractions are separated by different processing steps, such as screening, air classification, ballistic separation, separation of ferrous and non-ferrous materials, glass, stones and other foreign materials and shredding into a uniform grain size, or also pelletized.
- This produces a homogeneous material which can be used as a substitute for fossil fuels in e.g. cement plants, lime plants, coal-fired power plants or as a reduction agent in steel furnaces.