Mumbai is a city that receives 300 days of sunlight a year, making solar energy a limitless, and free resource. But what do most of us use instead? Electricity generated from coal, oil and gas that releases carbon into the air. On World Energy Conservation Day, Hindustan Times brings you the stories of individuals and institutions that have started powering their buildings with the sun’s energy — an office complex, a religious shrine, educational institutions, a museum and housing complexes — doing their bit to clean up the air, reduce dependency on the grid, and save on monthly electricity expenses too
1.Siddhivinayak goes solar for a greener future
What? Mumbai’s Siddhivinayak Ganpati temple at Prabhadevi is tapping the sun for its energy needs. A 20 kilowatt-hour (Kwh) solar plant, comprising 72 panels across 3,000 sqft, on the terrace of the five-floored Prathisthalaya temple building powers the lights and fans on every floor of the massive structure
How much do they save? The two-century old temple has reduced the monthly electricity bill by 30% and have been saving Rs40,000 a month for the past four years
How much did it cost? The temple spent Rs50 lakh on the project. The trust received Rs15 lakh from the government as tax rebate for the solar project
Why they did it? “With lakhs of devotees visiting our temple every day, our attempt was to encourage them to also take up renewable sources of energy so the carbon footprint on the city’s environment is reduced,” said Narendra Rane, chairman, Shree Siddhivinayak Ganapati Temple Trust. He said the temple uses only LED lights that consume less electricity.
2 The Vile Parle bungalow that uses the wind and the sun
What? Fourteen years ago, Harendra Shah, 70, and his brothers — Rajendra, 68, Pankaj, 66 and Shailesh, 60 — set up one of the first windmills in the city atop their seven-storeyed Dolat building, opposite Cooper Hospital at Vile Parle (West). They also installed nine solar panels to power basic electricity requirements. The solar panels and the windmill system produces 2 kWh peak power daily — 1.5kWh from the windmill and 500Wh from the solar panels — which runs fans, lights and a computer in each of the floors. A solar water heater installed on the rooftop is powered using two solar panels that heat up 1,000 litres of water daily. The water is then used in 18 bathrooms
How much do they save? The family saves 33% of their electricity bill every month — from Rs9,000 a month to Rs6,000 to power the whole building. In the past seven years, the family says it saved Rs2.5 lakh on electricity expenses
How much did it cost? The family set up the project at a cost of Rs5 lakh. They received a subsidy of Rs2.5 lakh from the state in three years. They recovered the cost of the project within seven years of inception
Why they did it? “All four of us are engineers, we knew the exact dynamics of such a project,” said Shah. “The solar-plus-wind energy hybrid system works as a stopgap arrangement during power failures. During the 2005 deluge, it helped us during power outages. On a sunny and windy day, we are able to access peak power of 2kW per day. During the monsoon, it drops to 1.5 to 1.7kWh a day,” said Rajendra.
3.The SoBo office that set up the largest solar power generation unit in Mumbai
What? In August, the city got its largest solar power plant setup at the Arcade building at MVIRDC World Trade Centre (WTC) at Cuffe Parade, Colaba. It is connected to the grid which allows the building to trade excess electricity generated. The 120-office complex has a 250 kilowatt peak power (KWp) system with 808 solar panels, spread across 25,000 sqft roof area. The panels generate 900 kilowatt hour (KWh) solar energy a day that caters to all consumption for the three-floor building, including the AC system.
How much do they save? The complex has been saving Rs45 lakh every year after four years of installation. The project reduced their annual electricity bill by 30%.
How much did it cost? Rs 1.75 crore
Why they did it? “Solar power is attractive as it is abundant and offers a solution to the negative effects of fossil fuel emissions and global climate change,” said Kamal M Morarka, chairman, WTC Mumbai, a non-profit organisation that helps in facilitating trade.
4.The museum that shines with solar power
What? The city’s largest museum, formerly known as Prince of Wales Museum of Western India and now called Chhatrapati Shivaji Maharaj Vastu Sangrahalaya (CSMVS), is not only home to natural and cultural artefacts but is one of the few museums in the world to use solar power. The museum has been using solar photovoltaic (SPV) technology to power 5% of its electricity requirements. With a total of 140 panels spread across two roof tops — 60 on one, 80 on the other — that were installed in two phases, 35 kilowatt electricity is being produced every month.
How much do they save? The museum’s total power requirement is approximately 3,000 units a day and with the help of the solar power plant, nearly 140 units can be generated during the day between 10am to 6pm, on a full sunny day. The museum saves Rs 6.5 lakh each year on electricity expenses.
How much did it cost? Rs 30 lakh
Why they did it? “The effect of climate change is visible as year on year temperatures are increasing. Rather than complaining about the deep wound that emissions have already created on the planet, we decided to switch over to alternate forms of renewable energy by adopting solar power,” said Sabyasachi Mukherjee, director general, CSMVS. “We intend to increase the electricity produced through solar energy to 100 kilowatt.”
5.The educational institutions that went the solar way
What? The management of Don Bosco educational institutions, with the help of an independent NGO Green Line installed solar panels on the roofs of five schools and one college. The project was piloted at Don Bosco High School, Matunga, and Don Bosco Provincial Building (headquarters for the solar panel project), where a 10 (kW) unit was setup a year ago. St. Dominic Savio High School, Andheri and St. Joseph’s High School, Wadala, have a similar setup of 10kW unit. Don Bosco High School and Junior College, Naigaon, and Don Bosco Senior Secondary School, Nerul and Navi Mumbai have also set up 20kW solar panels under this initiative. Don Bosco Institute of Technology, Kurla, is making use of power from an 110kW solar panel.
How much do they save? While the 10kW unit helps save 20% of the monthly electricity bill, the 20kW unit helps save 30%. However, the 110kW unit at Kurla is spread across a large area, which has high power consumption and helps save 25% of the monthly bill.
How much did it cost? On an average, a 1kW unit costs Rs1 lakh
Why they did it? “It is both lucrative and a solution for environmental issues,” said Father Savio Silveira, director, Green Line. “The initiative is aimed at educational institutes adopting environment-friendly systems.”
6.How the sun helped this Lokhandwala building to reduce power bill by 90%
What? The 16-floor Cliff Tower apartment with 62 flats at Lokhandwala complex uses solar power generated on their premises. A rooftop solar setup of 120 panels generates 30 kilowatt (kW) solar energy per hour, which lights up common areas, passage, terrace and compound lights along with running three lifts and five water pumps
How much do they save? The monthly bill of the complex is Rs55,000. After installation of this clean energy source, they save Rs50,000 every month. “This means what we were spending every month will now be spent in a year, reducing our annual expenditure by 90%,” said R Sahgal, secretary, Cliff Tower.
How much did it cost? With no maintenance fee required for the next 25 years, the cost incurred by residents was Rs23 lakh to set up the project. That amount is estimated to be recovered over the next four years
Why they did it? “In 10 months of a year, the panels generate 100% solar power, but there is a 35% decrease during cloudy days in July and August,” said Sushil Jain, committee member and resident. “With an interest to install a similar project, neighbouring societies have been regularly visiting us to understand the concept.”