Moving away from the usual carbon-emitting process of using electricity generated from burning coal and gas, one of the popular temples in Mumbai has gone the solar way and reduced their monthly electricity bill by 30%.

The two century-old Shree Siddhivinayak Ganapati temple at Prabhadevi has been saving Rs 40,000 per month for the last four years. A 20 kilowatt-hour (Kwh) solar rooftop project, comprising 72 panels on top of the five-storey Prathisthalaya temple building is used to power lights and fans on every floor, reducing their dependency on the grid.

A Mumbai house with two bedrooms on an average uses around 8kwh to 10 kwh power every day.

“With lakhs of devotees visiting our temple every day, our attempt is to encourage them towards taking up renewable sources of energy so that the carbon-footprint on the city’s environment can be reduced,” said Narendra Rane, chairman, Shree Siddhivinayak Ganapati Temple Trust adding that the temple complex uses only power-efficient LED lights. “We have plans to install a 100Kwh project across remaining parts of the temple to reduce 100% dependency from the grid in the next two years.”

Experts said that the city’s power situation can be transformed if we construct buildings and temples which generate their own electricity and move towards the concept of ‘zero energy’ homes. “In a city like Mumbai, where residential tariffs are high, such a project will be very cost-effective. Not to mention the reduction in carbon footprints,” said Ranjan Banerjee, head of department, department of energy, science and engineering at Indian Institute of Technology (IIT) Bombay.

The temple also adopted rainwater harvesting in 2011, and in the last five years they have saved over 35 lakh litres of rainwater, which is reused for non-potable purposes such as washrooms and watering plants at the half-acre temple garden. The 3,000-sq-ft rooftop from two temple buildings acts as the catchment area, that sends collected rainwater via pipes to an underground well with a capacity of 20,000 litres.

Even the flower waste and coconut shells from daily offerings, amounting to 1200kg per day, are recycled by a dedicated team from the trust. They collect and segregate used marigold flowers into – clean and dirty petals. While the clean ones are recycled to make an orange paste, used to colour laddoos (see box) and tilak for devotees, the dirty petals and coconut shells are composted to make manure used at the temple garden.

“We wanted to make sure that everything that the temple receives should be reused. Considering the water shortage faced by the city in 2015, the rainwater harvesting facility reduced our dependency upon the civic body,” said Rane. “We have managed to effectively treat our organic waste and have already initiated a plan to recycle dry waste through the civic body’s help. Our attempt is to become Mumbai’s first zero garbage temple.”

Waste water from across the two-and-a-half acre temple premises is treated at sewage treatment plant located at its basement. Along with the saved rainwater, 25,000 litres of waste water is treated every day and reused at washrooms and garden maintenance.