Waste to Energy

Context: Recently Karnataka Chief Minister B.S. Yediyurappa laid the foundation stone for a 11.5 MW waste-to-energy plant near Bidadi. This plant is expected to process 600 tonnes per day of inorganic waste.

What is the significance  of Waste to Energy Plants?

• 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.

Why it is needed?

• Bengaluru generates close to 5,000 tonnes of waste daily, of which about 2,500 tonnes is organic, about 1,000 tonnes inert material (sweeping waste) and 1,500 tonnes inorganic.
• This inorganic material, 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, and can be used to generate steam energy, which can be converted into electric energy instead of burning coal and other materials used in traditional waste-to-energy plants.
• At present, Inorganic waste that is not fit for recycling 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 city’s dependency on unscientific landfills, reduce fire accidents, and provide a permanent solution to recover value from inorganic waste.

What are the challenges faced by Waste to Energy plants in India?

• Poor quality of waste: The Waste to Energy 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 in the city is more than 15%-20%.
• Lack of segregation at source: Since segregation at source doesn’t happen in the city, the collected waste material needs to be sieved using 80mm-100 mm sieving machines, which lets through organic material with more than 80mm-100 mm particle sizes into the inorganic waste. In addition, the sticky silt and soil particles will also reduce the calorific value.
• Cost of Power is high: Generally, the tariff at which the power is purchased by to energy plants across the country is around ₹7-8 KwH which is higher than the ₹3-4 per KwH generated through coal and other means. This could be a serious challenge, as the selling price of power cannot be increased corresponding to the purchasing price.