A cooperative housing society in Mahim, which has been recycling its waste for the past six years, has now taken another step to reduce its carbon footprint. They have installed solar panels on their rooftop that will help them save Rs3 lakh every year in electricity bills.
Our Lady of Vailankani Housing Society at Mary Nagar that has two buildings — a 12-storey one with 112 flats and a seven-storey building with 48 flats — has set up a solar power panel with a capacity of 10 kilowatt (kW). The power produced by the panels would light up common areas (lobbies, staircases). A Mumbai house with two bedrooms, on an average, uses 8 to 10 kW electricity daily.
Setup at a cost of Rs 7.5 lakh earlier this month, the 32 panels with solar photovoltaic cells will substantially reduce the society’s monthly electricity bill. The residents have estimated that their monthly electricity bill which comes to Rs 55,000 will be reduced by Rs 28,000.
It is one of first housing complexes in Mahim to use solar power to meet part of their energy needs. “Keeping the sermons of the church in context of the imminent issue of climate change, we have like-minded citizens who want to do their bit to protect the environment,” said AM Sodder, secretary of the housing society. “Not only are we harnessing energy that reduces the carbon footprint, but also our garbage is not adding to the city’s solid waste management woes.”
A recent study by the Indian Institute of Technology Bombay (IIT-B) and think-tank Observer Research Foundation (ORF) found that Mumbai, with its ample sunlight and vast array of roots, has the potential to generate 1.72 Giga Watt Peak (GWp) solar energy through photovoltaic (solar) panels installed atop buildings. This means solar energy can take care of half of Mumbai’s power needs.
The buildings also have a net-metering system, which allows surplus power generated by solar panels to be exported back to the grid. At the end of a financial year, the society will be charged by the electrical power supplier only for the ‘net usage’.
Although this is their latest green initiative but not the only one. The housing society has been recycling kitchen and garden waste through composting for the past six years. They have managed to save 2.19 lakh kg of organic waste from reaching the city’s overburdened landfills and generated almost three tonnes of manure. The residents have created four concrete compost pits located at one end of the complex where 10 kg of daily wet waste (vegetable, kitchen discards) is dumped. “We use sugarcane stems with gunny sacks at the base of each compost pit to ensure enough moisture. After dumping the waste, we add sawdust, dried leaves and water to breakdown the compost into manure faster,” said Inacio Ciriaco Fernandes, manager of the residential complex.
He added that the manure is used to nurture three gardens within the complex. “We sell excess compost at Rs15 per kg to residents and even other nearby societies as the finished product is voluminous,” said Fernandes.