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Zero Head Hydro Turbine

Nripen Kalita is the inventor of a water turbine that can both light up rural homes and pump water to irrigate farmers’ lands in Assam, India.

Inspired by his wife and the Archimedean screw, Nripen Kalita is known as the inventor of the zero-head water turbine, a low-cost piece of equipment that can generate power to light up rural homes and run pumps to irrigate farmers’ lands.  

“I belonged to a rural area with limited electricity and where flooding was an annual problem,” he said. “And this problem gave me the impetus to come up with an idea to use the force of water in a constructive way and produce electricity. Every monsoon, as the water level in the rivers rose, I used to think of ways to utilise hydro power in a cost-effective manner.”  

Nripen began his career repairing television sets and other electronic items. His invention first occurred to him many years ago when he tried to bring electricity to his own house.   

“Necessity is the mother of all inventions,” he added. “My motive was to develop electricity in rural areas where power cuts are rampant.” 

In 1998, he developed a zero-head hydro turbine using a bamboo platform to keep the machinery afloat. But he soon realised that using bamboo was not practical and replaced it with iron.   

“The model has a spiral offset of blades, much like the Archimedean screw (one of the earliest hydraulic machines).” His zero-head hydro turbine consists of an iron wheel with rotor blades, some pulleys, an alternator and a lot of wires -- lowered into the river water -- with two hollow plastic drums attached to the device to keep it afloat. The turbine is then placed under water, which rotates at a low speed but a high torque when water passes through it. A compound gear mechanism attached with an armature coil converts the kinetic energy of water to electric energy. A submersible pump is attached with the turbine set for irrigation purposes.   

The turbine is novel in that it is portable and eliminates the need for a dam. It is economically viable: construction and installation costs are much less than traditional hydroelectric interventions. It is built to be set up in uncertain terrain such as plains or mountains.  

“We have to think beyond our enjoyment and modern-day world,” Nripen said. “Without innovation there can never be progress and development in society. For the betterment of our life new things need to be invented.”