Delhi’s waste collection points and overflowing landfills give an impression of massive quantities of mismanaged waste, which is best incinerated at waste-to-energy (WTE) plants.

But a new assessment by the Centre for Science and Environment (CSE) has revealed that only 13% of Delhi’s waste is of high calorific value and can be incinerated to generate energy— the rest can either be treated biologically or recycled.

Delhi has already constructed three WTE plants with the capacity to handle nearly 50% of its municipal waste and is planning to build a fourth one with no ideas about where the high calorific value waste will come from to feed these plants. As of now, mixed waste, with even inert material, is landing up at WTE plants.

CSE’s analysis, “To Burn or Not To Burn”, also suggests that WTE plants come at a steep environmental cost as they require continuous monitoring of emissions. For example, the National Green Tribunal (NGT) had directed on February 2, 2017, that the Okhla plant must make emissions data public. Burning mixed waste, as is the case at the Okhla plant, can lead to emissions of toxic gases, including dioxins and furan, in the absence of proper emission control systems.

But when CSE researchers accessed the emissions data in June 2017, it hadn’t been updated since 2016. Researchers also found that the Central Pollution Control Board (CPCB) is only ensuring installation of emission monitoring equipment at WTE plants but not in compliance with standards. This leaves residents in the vicinity of these plants vulnerable to toxic emissions.

The assessment was released last week on the status of WTE plants around the country.

According to a Niti Aayog agenda report for 2017–20, the Swachh Bharat Mission has a deliverable of 330MW of waste to energy generation for 2017–18 and 511MW for 2018–19 — an increase of over 400% from the current installed capacity.

“The solid waste management rules, 2016 say only segregated, non-recyclable high calorific waste be sent to WTE plants. Of the 55 metric tonnes of municipal solid waste (MSW) generated every year, only about 15% can be classified as non-biodegradable, non-recyclable, high calorific value waste. This translates to about 30,000 tonnes per day of waste which can be fed to the plants. But the total waste treatment capacity for 48 existing, under-construction and proposed WTE plants is over 37,000 TPD,” Swati Singh Sambyal, programme manager at CSE, said.

The analysis also found that WTE plants are expensive and the tariff of WTE generated power, the highest. Compared to Rs 3–4 per kWh from coal and solar plants, WTE plants sell electricity at about Rs 7/kWh which is why discoms in many cities are not in favour of buying power from them, the analysis states.

A WTE plant uses up around 25% to 30% of power generated as in-house auxiliary power to run machines. For an incineration plant to treat about 1,000 tonnes of waste a day, the capital cost alone can be as much as Rs 200 crore.

Surprisingly, companies and investors are still finding waste to energy economically attractive, mainly because of the subsidies offered by the Centre.

“I don’t think Niti Aayog has recommended only mass incineration technology for waste to energy plants. Bio-methanation is also an option. The central government cannot impose on state governments to choose incineration. I had advised the Andhra government against mass incineration but they didn’t pay heed. Mass incineration is inefficient and risky. Refuse-derived fuel technology costs about Rs 20 crore per MW as opposed to Rs 5 crore from thermal plants,” professor Shyamala Mani, of the National Institute of Urban Affairs, said.

First Published: Feb 16, 2019 11:06 IST