WASTE TO ENERGY
Waste-to-Energy (WtE) or Energy-from-Waste (EfW) is the process of generating energy in the form of electricity and/or heat from the primary treatment of waste, or the processing of waste into a fuel source.
WtE is a form of energy recovery.
Most WtE processes generate electricity and/or heat directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels.
WHICH TYPE OF WASTE IS USED TO PRODUCE ENERGY?
- Waste-to-Energy projects use non-recyclable dry waste to generate electricity.
- The process increases the State’s power generation capacity and eases the Solid Waste Management (SWM) burden.
- Generally, solid waste in India is 55-60% biodegradable organic waste, which can be converted into organic compost or biogas; 25-30% non-biodegradable dry waste; and around 15% silt, stones, and drain waste.
- Of the non-biodegradable dry waste, only 2-3% – including hard plastics, metals, and e-waste – is recyclable.
- The remainder consists of low-grade plastic, rags, and cloth that can’t be recycled.
- This fraction of the non-recyclable dry waste is the most challenging portion of the present SWM system; the presence of these materials also reduces the efficiency of recycling other dry and wet waste.
- Waste-to-Energy plants use this portion to generate power. The waste is combusted to generate heat, which is converted into electricity.
- Waste-to-Energy plants in major cities could also consume a portion of the non-recyclable dry waste generated in Urban Local Bodies (ULBs) nearby.
WHY DO WASTE TO ENERGY PLANTS FAIL?
While waste-to-energy plants seem like a simple solution, they have several challenges for them to becoming feasible.
- Low calorific value of solid waste in India due to improper segregation –
- The calorific value of mixed Indian waste is about 1,500 kcal/kg, which is not suitable for power generation. (Coal calorific value 8,000 kcal/kg.)
- Biodegradable waste has high moisture content and can’t be used for power generation; it should be composted instead.
- The calorific value of segregated and dried non-recyclable dry waste is much higher, at 2,800-3,000 kcal/kg, sufficient to generate power.
- However, segregation (ideally at the source, if not at the processing plant) should be streamlined to ensure the waste coming to the facility has this calorific value.
- High costs of Energy Production –
- The cost of generating power from waste is around Rs 7-8/unit.
- In comparison, the cost at which the States’ electricity boards buy power from coal, hydroelectric, and solar power plants is around Rs 3-4/unit.
- While State electricity boards are considering purchasing power from newer renewable energy sources like waste-to-energy, the price of the power generated needs to be reduced.
- Improper Management –
- Many waste-to-energy projects have failed because of improper assessments, high expectations, improper characterisation studies, and other on-ground conditions.
- Proper Segregation at Source –
- Setting up waste-to-energy projects is complex and needs the full support of the municipality, the State and the people.
- To overcome its various challenges, the municipality must ensure that only non-biodegradable dry waste is sent to the plant and separately manage the other kinds of waste.
- Proper Planning & Execution –
- The municipality or the department responsible for SWM should be practical about the high cost of power generation, and include the State electricity department.
- It is also crucial to conduct field studies and learn from the experience of other projects.
LIST OF WASTE TO ENERGY PLANTS IN INDIA