PIB TrackerDung makes manure, mixed waste makes gas - and both recover about 14%
Four waste-to-energy projects, four sets of units. The one ratio that compares them shows Prayagraj getting three times Gwalior's fuel from a tonne of feedstock.
What happened
- Prayagraj: a multi-feedstock bio-CNG plant, 343 tonnes/day of organic waste to about 21 tonnes of bio-CNG and 28 tonnes of compost.
- Gwalior: a 100 TPD compressed biogas plant at Adarsh Gaushala, Rs 31 crore with Indian Oil, making 2 tonnes of CBG and 10-15 tonnes of bio-manure daily.
- Bowenpally, Hyderabad: about 10 tonnes of market waste to 400-500 units of electricity and 30 kg of biofuel a day - the bill halved from about Rs 3 lakh a month.
- Adalaj, Gandhinagar: two plants of 90 cubic metres/day, dung from 222 cows, cooking for 500+ people and displacing 30 LPG cylinders monthly.
- Prayagraj expects to reach about 45,000 households and cut roughly 57,000 tonnes of emissions a year.
For Prelims
- Biogas versus bio-CNG/CBG: both come from anaerobic digestion. Biogas is raw (roughly half methane) and burnt on site; Compressed Bio-Gas is upgraded and compressed to be sold as vehicle or piped fuel - which is why one lights a market and the other enters a gas grid.
- The CBG-CGD Synchronisation Scheme: lets CBG producers sell into City Gas Distribution networks, reaching users through the fuel cascade route. Without it a CBG plant has no guaranteed buyer.
- The slurry is the second product: digestate is nitrogen-rich and works as organic fertiliser - which is why Gwalior yields 10-15 tonnes of bio-manure and Prayagraj 28 tonnes of compost daily.
- Why dung yields less gas: cattle have already digested it. Mixed municipal and crop waste still holds the energy, which is the whole of the 6.1% against 2.0% gap.
- Multi-feedstock matters: Prayagraj runs on wet waste, paddy straw, cattle dung and poultry litter - so it also gives paddy straw a paying use, which is the standard answer to stubble burning.
- Swachh Bharat Mission-Urban 2.0: the phase under which municipal waste moved from collection and disposal to processing and resource recovery. SBM was launched in October 2014.
- Bowenpally's replication: five further plants funded at Gudimalkapur, Gaddiannaram, Erragadda, Alwal and Saroornagar, each sized to its own yard's waste.
- The Gujarat enabler: the state's Institutional Biogas Plant Scheme and the Gujarat Energy Development Agency (GEDA) provided the policy and financial support for the Adalaj campus.
For UPSC: The four cases give you the whole circular-economy argument in measurable form. Use them on solid waste management and SBM-Urban 2.0, on the circular economy where the by-product is the second revenue line, on stubble burning where paddy straw acquires a buyer, and on decentralised renewable energy - a market, a campus, a cowshed and a city each solving the same problem at a different scale.
What it is NOT: Only one of the four projects carries a cost figure, so three cannot be assessed for viability and none has a payback period. Each reports output in a different unit - cubic metres, tonnes of CBG, kilograms of biofuel, units of electricity - which is why the backgrounder never compares them and a reader has to. No national figures appear at all: no count of waste-to-energy plants under SBM, no installed capacity, no share of municipal solid waste processed this way. Prayagraj gives a design capacity of 343 tonnes and a wet-waste supply of 125 without stating actual throughput. Emissions savings are given for one project and not the others, and no tipping fee, gate price or offtake tariff appears anywhere.
For Mains
Syllabus: GS3.14 · GS3.9 · Linkage L2
Anchor
Prayagraj turns 343 tonnes of mixed organic waste into about 21 tonnes of bio-CNG a day: a fuel yield of 6.1 per cent. Gwalior turns 100 tonnes of cattle dung into two tonnes of compressed biogas: 2.0 per cent. Three times the fuel from the same tonne of feedstock. But count the solid by-product as well and the two converge - 14.3 per cent recovery at Prayagraj, 14.5 per cent at Gwalior. The feedstock does not change how much you recover. It changes whether you recover fuel or fertiliser.
Substantiation (data)
The four projects are genuinely different scales of the same idea. Prayagraj also makes 28 tonnes of compost daily and has raised its wet-waste intake from 7-8 tonnes to about 125, aiming at 45,000 households and roughly 57,000 tonnes of avoided emissions. Gwalior cost Rs 31 crore on five acres with Indian Oil and produces 10-15 tonnes of bio-manure a day from 10,000 cattle. Bowenpally converts about 10 tonnes of market waste into 400-500 units of electricity, halving a Rs 3 lakh monthly bill. Adalaj runs a 500-person kitchen on 90 cubic metres a day and 222 cows.
Position
The by-product is what makes these work, and it is usually treated as an afterthought. A plant judged only on gas yield would rate Gwalior a failure at two per cent; a plant judged on total recovery finds it matching Prayagraj. Digestate displaces chemical fertiliser, which is a subsidised import-dependent input, so the manure line is doing fiscal and agronomic work that no energy accounting captures.
Counterpoint
Only Gwalior has a price attached: Rs 31 crore for two tonnes a day, or about Rs 15.5 crore per tonne of daily CBG capacity. Nothing in the document lets you check whether that is good value, because the other three projects report no capital cost at all. Bowenpally's saving works out to roughly Rs 11 a unit against grid supply, which is favourable - but without the plant's cost, the payback period is unknowable.
Problematisation
This is the second PIB backgrounder in three days to measure local initiatives in incommensurable units and leave the comparison to the reader - the plastics document of 25 September did the same thing with five schemes. Four case studies are evidence that something works somewhere; they are not a programme. The absent numbers are the national ones: how many such plants exist under SBM, what capacity they hold, and what share of India's municipal organic waste actually reaches one.
Conclusion
Treat waste-to-energy as a two-product business and the economics stop being marginal. The question these four stories raise and do not answer is whether the model scales past the captive feedstock - a market, a gaushala and a campus each sit on a guaranteed daily supply of one kind of waste, which is exactly what a city does not have.
Deploys into: Circular economy and resource recovery · Swachh Bharat Mission-Urban 2.0 · Compressed bio-gas and the CBG-CGD scheme · Paddy straw, stubble burning and organic fertiliser
PIB Backgrounder (Ministry of Housing and Urban Affairs) · 2026-09-27 · PRID 2315501 · PIB source ↗