Feasibility of waste-to-energy plant

(MainsGS3:Conservation, environmental pollution and degradation, environmental impact assessment.)

Context:

• There are around 100 waste-to-energy projects around the country but only a handful of them are operational, thanks to various production and operation challenges.

Waste-to-energy projects:

• 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 and 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 as 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.

Several challenges:

• While waste-to-energy plants seem like a simple solution, they have several challenges en route to becoming feasible.
• The 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. 
• 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.
• The high costs of energy production as the cost of generating power from waste is around Rs 7-8/unit, while 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 halve.
• Many waste-to-energy projects have failed because of improper assessments, high expectations, improper characterisation studies, and other on-ground conditions.
• The quantity of waste generated by cities varies due to multiple factors, including season, rainfall, and the floating population. 
• Importantly, waste-to-energy projects can consume only non-recyclable dry waste, which is about 25% of the waste; they are expected to only use segregated non-recyclable dry waste as well, which is the only type of waste with a sufficiently high calorific value.
• But in reality, these projects are often expected to manage all types of waste generated in the city, which is only bad for the projects.

Way forward:

• Operating waste-to-energy projects also depends on parameters like the municipal collection efficiency, waste segregation, moisture content, and the operational efficiency of existing biodegradable-waste-processing plants.
•  If these plants have operational woes (as is common), the nature of waste will change drastically to have high moisture content and low calorific value, which will compromise power generation.
• 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.
• Importantly, the municipality or the department responsible for SWM should be practical about the high cost of power generation, and include the State electricity department, perhaps as a tripartite agreement between the municipality, the plant operator, and the power distribution agency. 
• It is also crucial to conduct field studies and learn from the experience of other projects.

Conclusion:

• 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.