While battery manufacturers and solar power companies are struggling to develop batteries that would be cheap, smaller in size and can store power for days, an engineering college in Kolkata has devised a combo of solar based generation and power storage system that can supply power perpetually 24 hours a day all through the year at a fraction of conventional battery cost. It is scalable to any size and are suited for any hilly area as well as multi storeyed buildings. A 100 kilowatt pilot project is already being planned in hills of East India, while its smaller version, producing 100 watts of power 24×7 is now running in Kolkata on a four storeyed building.
“The system is hugely scalable. It can be set up on a building that can generate 100 watt or more throughout the day to even a few megawatts at fraction of battery costs,“ said SP Gon Choudhury , Chairman of Renewable Energy College in Kolkata.
We are in talks with the centre for funding the project,“ he said.
The system consists of a solar pump basically solar modules that would generate power during day and run a water pump. It also consists of two water tanks at two different elevations. The upper tanks would release water at half the speed at which it receives water from the lower pump. The falling water would rotate a turbine an equipment that generates electricity when rotated by an external force falling stream of water from the elevated tank in this case.
During day , water from the lower tank would be pumped to the upper tank. A portion of this water also flows down simultaneously into the lower tank generating power. The rest of the water in the elevated tank keeps flowing down during night, thus producing power the entire day .
According to him, a 200 meter by 600 meter tank at two levels separated by 50 meters would be good enough to generate 1 mw of power non-stop. It is likely to cost around Rs 9 crore the smaller the power requirement, smaller would be the required investment.
At this rate, solar power of 2mw would be required to generate 1 mw of power through the day . There are plans to do rainwater harvesting in hills which would fill tanks. Once filled, there would be no requirement for a river or steady flow of water from external sources. A portion of this water would evaporate, but it would get replenished during the next bout of rains,“ said Gon Choudhury .
According to experts it is a variant of pumped storage system added with solar generators and filled with rain water doing away with a steady flow of water in the lower tank.