New Delhi, Dec 20 : A top scientist at National Physics Laboratory here has said that industry should come forward to commercialise the concept of the hydroelectric cell as it has the potential to be a very cheap source of electricity. [NK Technology] The inventor of the cell that produces electricity from water, R.K. Kotnala, the Chief Scientist at NPL, urged industry leaders to come forward and help improve the workability of the cell, which, he said, can be a great source of green energy.