Around 3,500 metric tonnes of garden waste have generated 300 megawatt (MW), almost a tenth of the city’s daily electricity needs, at a waste recycling plant in Ghatkopar in the past two years.
The city’s electricity demand is between 3,500MW and 3,100MW a day, according to a report by the union environment ministry and Institute of Chemical Technology, Matunga.
The Brihanmumbai Municipal Corporation (BMC) converts garden waste such as grass, leaves and hedge trimmings into fuel pellets in its first-of-its-kind facility on a 4,000-sqft plot near Damodar Park, off LBS Road.
“Earlier, a large quantity of horticultural waste from the garden department was being sent to dumping grounds. Leaves and tree branches were a major cause of recurring fires. So the solid waste management (SWM) department has decided to process the waste and reuse it,” said Praful Jadhav, assistant engineer, SWM, N-ward, and incharge of the project. “We wanted to keep the project low key [for two years] to ensure its successful implementation.”
In 2014, the BMC appointed a team of engineers from the CIPL Resurge Private Limited (CRPL) as contractors to carry out the work. CRPL said close to 30 tonnes of garden waste from across Mumbai is brought to the plant daily by municipal dumpers. The organic waste is converted into cylindrical 10 millimetre (mm) pellets and 90mm briquettes – a mix of garden waste, sawdust, wood chips, peat, or paper – by four machines.
“Combustible biomass material such as fuel briquettes work as an alternative to firewood, wood pellets and charcoal,” said Viral Mehta, plant manager, CRPL. “Close to 8 tonnes of these 90mm briquettes are collected every two days. We send it to various tyre companies, beverage factories and ceramic industries at Bhandup, where the briquettes are dissolved in large boilers and converted into steam that further helps in moving turbines to generate electricity.”
Around 12 tonnes of briquettes are needed to produce 1 MW of electricity. A pilot 135-KW plant is being set up at the Ghatkopar facility for its in-house needs.
Mehta said CRPL is in the process of acquiring a patent for generation of this form of renewable energy, which has previously been done across the US, Europe. The total cost of setting up the project was Rs2 crore. “It will help replace furnace oil that was earlier being used by industries to generate electricity,” he said.
Although the briquettes have a lower calorific (heat-producing) value than oil, they cost only Rs5 a kg, much lower than Rs30 a litre for furnace oil.