What took off as a pilot project to illuminate around 10 dingy shanties in a Kolkata slum would now light up at least 10 million homes across the country with no pollution.
It is a simple device that traps sunlight and just concentrates it inside a dark room. Unlike photovoltaic cells, which need to convert light energy to electrical energy, the new device known as a Micro Solar Dome doesn’t need any such conversion. It just acts on the principles of reflection.
“After the pilot project proved successful in Kolkata, a few hundred such domes were installed in shanties of Lalbagh in Delhi and sub-urban Mumbai. It was later replicated in other parts of the country too. Now the Union government is planning to install such solar domes in 10 million shanties and huts in both urban and rural areas across India. 2018 is our target,” said SP Gon Choudhury, the renowned renewable energy expert, who developed and patented (provisional) the device.
This is how it works. The device captures sunlight through a transparent semi-spherical upper dome installed on the roof. The light passes through a sun tube having a thin layer of highly reflective coating on the inner wall of the passage. The light is then forced to concentrate inside a dark room through another dome fitted on the ceiling.
Experts believe that solar domes would be a boon for millions of families living in slums and rural areas which do not have access to electricity. It would also be particularly useful for those houses which remain dark even during the day and people have to either light bulbs or kindle lanterns even while the sun is shining.
“There is a photovoltaic version too in which solar panels are attached to the device. The cells get charged when the sun shines. At night when there is no sunlight, the charged up cells are used to light bulbs. So you have light both during the day and night,” he said.
Experts estimate that installing his device in 10 million homes could save 1,700 million units of energy in a year. As most of our electricity comes from coal-based thermal power plants, installing this device would also mean that at least 12.5 million tons of carbon dioxide is not added to the environment in one year.
At present the photovoltaic integrated solar dome costs around Rs 1,200 and the non-photovoltaic version costs around Rs 500. These figures are expected to go down further by at least Rs 200-Rs 300 when the domes are manufactured on a large scale and linked with subsidies under various schemes of the ministries of urban development, rural development and ministry of new and renewable energy.
“So we can not only have the slums and rural areas lit but also expect some fresh air at a minimum cost. It would also act as a fillip to the Clean India, Green India mission,” Choudhury said.
With the news of success travelling far and wide, proposals have also started pouring in from both the east and west including Bangladesh and a few countries from the West Asia.