Why a waste-to-energy plant is not the answer to Chennai’s garbage problems

GCC has floated a tender for a waste-to-energy plant in Chennai's Kodungaiyur. Here's a lowdown on WTE plants and their environmental impact.

Chennai generates about 6,000 metric tonnes of garbage every day. As the city’s population continues to grow, waste generation is expected to increase even more. Not to mention the huge quantities of legacy waste currently accumulating in the Kodungaiyur and Perungudi dump yards. How will the Greater Chennai Corporation (GCC) effectively manage these vast amounts of waste?

As this is a common urban issue, the government has proposed a solution already implemented in several other Indian cities. It suggests establishing an integrated waste management project facility, including a waste-to-energy (WTE) plant. It would come up in the North Chennai region, which is already heavily polluted.

‘No-Burn Chennai’

The proposed project entails establishing Integrated Solid Waste Processing Facility (IWPF) sites at specified locations. These facilities will process waste generated from Zone 1 to Zone 8, as well as the segregated, non-recyclable-combustible fraction from Zone 9 to Zone 15.

At a cost of Rs 1,026 crore, the plan is to burn 2,100 tonnes of waste every day. Given the catastrophic impacts of industrial pollution, experts say North Chennai cannot afford to host a waste-to-energy plant.

Civil society organisations Poovulagin Nanbargal, Chennai Climate Action Group, Centre for Financial Accountability (CFA) and Citizen consumer and civic Action Group (CAG) together organised a discussion ‘No-Burn Chennai’ on the adverse impacts of WTE plants on May 11. Here is an explainer based on the deliberations and experts’ views on the subject.

Read more: Chennai’s ongoing battle to improve waste management

What is waste-to-energy incineration?

Simply put, waste-to-energy is explained as burning the waste to generate power. The operation of an incinerator in a WTE plant is similar to that of a thermal power plant except that the coal is replaced with waste in the WTE.

Internal functioning of an incinerator in Waste to Energy Plant
As shown in the picture, trucks dump tonnes of waste into the storage pit. Using a crane, the waste dumped in the pit is lifted and sent to the furnace. When the waste is burnt, heat is generated to produce electricity just like a thermal power plant burning coal to generate electricity. The collected wastewater and ash is then sent for treatment or disposal. Pic Courtesy: A study titled India’s waste-to-energy paradigm, a policy, social and environmental perspective by the CFA

As simple as it sounds, it is a complex technology. “For the effective functioning of the WTE plant, many parameters have to be in place,” says DK Chythenyen from CFA.

He explains six such parameters:

  1. The calorific value of the waste: The calorific value is the amount of heat or energy produced when waste is burnt. For instance, when we cook using firewood, it takes time, while the same can be done much faster using LPG. The calorific value of burning waste should be high for effective functioning of the WTE plant.
  2. Air-fuel Ratio: The ratio of the waste sent inside for burning to the air suction should be maintained.
  3. There should be proper mechanisms to mix both air and waste.
  4. The speed of combustion should neither be too fast nor too slow.
  5. Temperature of the rotary kiln: There is a need to maintain a minimum temperature of 1,000 degree Celsius in the boilers.
  6. Minimum retention time: The WTE incinerators require to maintain two seconds of retention time for flue gases in the secondary combustion chamber.

Proposed location of WTE plant

Map of the sites selected for setting up the WTE plant in Chennai
The sites selected for setting up IWPF in Chennai are on the northwestern side of the Kodungaiyur dumpyard as shown in the map. Pic courtesy: Tender document of WTE plant by GCC

Lessons from previous waste-to-energy plants in India

The first WTE plant came up in Timarpur in Delhi in 1987. It ran for 21 days of trial operations before shutting down due to the poor quality of incoming waste.

“It required waste with a net calorific value of at least 1,462.5 kcal/kg, but the supplied waste’s calorific value was 600-700 kcal/kg. Plant operators tried to supplement the combustion with diesel fuel but were unsuccessful,” points out a CFA spotlight report titled ‘India’s waste-to-energy paradigm, a policy, social and environmental perspective.’

A WTE plant was commissioned again in Okhla (Delhi) in 2011 to burn 2,000 tonnes of garbage. In 2024, around 8,000 tonnes (70%) of Delhi’s garbage is being burnt every day in Okhla WTE. There are also plans to expand the facility to burn an additional 7,000 tonnes of garbage and establish a few more WTE plants. “This means Delhi will end up burning 99% of its garbage,” says Chythenyen.

The Delhi Pollution Control Board and the National Green Tribunal have slapped fines of Rs 5 lakh and Rs 25 lakh respectively on the said plant for releasing toxins like dioxins and furans (nine times) higher than the permissible limits, into the air, and violating other pollution parameters.

“As a result, citizens living in Delhi breathe the worst air in the world and lose about 12 years of life expectancy to air pollution,” he adds.

Read more: Chennai’s woes with bio-medical waste dumping

How will a waste-to-energy plant affect Chennai’s climate?

According to a report in Down to Earth, 14 more WTE plants of 130 MW capacities have been installed in India since then. Of these, half have closed down and the remaining are under scrutiny for environmental violations. Low calorific value, the financial viability of the technology and inefficient operations were the reasons behind the closing of WTE plants in Vijayawada, Bengaluru, Kanpur, Hyderabad, Lucknow and Karimnagar.

Referring to the Chennai Climate Action Plan (CCAP) report, Chythenyen says, “The CCAP has stressed the need to adopt source segregation and decentralised waste processing systems instead of centralised WTEs as a solution to decarbonisation. This alone will affect a 90% reduction in GHG emissions from waste by 2050. Now, the government is proposing the WTE, in contradiction to its own report.”

The proposed WTE in Kodungaiyur will burn about 2,100 tons of mixed garbage a day or about 33% of the total garbage generation in Chennai. “This will emit about 3,400 tons of carbon dioxide daily from a single WTE plant, which would be equivalent to the emissions from about 10 lakh cars at a time. And the power generation will be a meagre 21 MW. This will fulfil only 0.1% of Tamil Nadu’s power requirement,” he adds.

“Kodungaiyur area already has the second highest land surface temperature of 42°C, compared to just 28.5°C in Pallikaranai. The establishment of the WTE will further affect Chennai’s climate,” he adds.

Other impacts of a waste-to-energy plant in Chennai

Speaking on the health impacts, Dr Vishvaja Sambath, Environmental Health Researcher from Chennai Climate Action Group (CCAG), says, “The presence of heavy metals like mercury, lead and arsenic can also cause poisoning, while toxins like dioxins and furans have been proven to cause cancer. It will also lead to various health issues like miscarriages, skin diseases and respiratory issues,” she adds.

The NGT order on the existing pollution from industries in North Chennai had earlier directed the Tamil Nadu government to conduct a carrying capacity study to analyse if the region could take any more industries. “Without having that data, bringing more such industries will only create more havoc,” Vishvaja adds.

“Those living on the far southern end of Chennai might think that they need not be bothered about the pollution caused by WTE in Kodungaiyur. However, the pollutants from the WTE would contaminate water bodies like Retteri and Puzhal (one of the major sources of water for Chennai), which will directly affect all the residents. WTE not only affect the waterbodies but also the air and soil,” says Afroz, a researcher from Citizen Consumer and Civic Action Group (CAG).

He further adds that the WTE plant will take a toll on the jobs of hundreds of people from the informal sectors like waste pickers, scrap dealers, recyclers and so on, who play a major role in segregating the recyclable waste from landfills.

Pin responsibility on the manufacturers

We have seen the Greater Chennai Corporation creating awareness during the Bhogi festival urging people not to burn the waste in open spaces. “However, the government proposes to do the same, except on a large scale using a technology that has failed in other places,” Afroz adds.

Stressing the need to pin the responsibility on manufacturers, Geo Damin from Poovulagin Nanbargal says, “While the government bans single-use plastics, which are mostly used by small-scale vendors, it has failed to pin the responsibility on the multinational companies that pack several products in plastic bags that end up in landfills. Rather, the government has been giving subsidies to those MNCs, thus pushing up the cost of environmentally-friendly products.”

What are your thoughts on this move by the government? Share in the comments. Citizens who want to know more about the WTE plant proposed to come up in Chennai, can access the tender document published by GCC here.

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