Generating electricity from water is nothing new and there are a lot of dams around the world doing the same thing. However, engineers in Hong Kong wanted something to power the water quality monitoring instruments in the water mains, without sourcing any grid electricity. While the water mains carry fast moving water, generating electricity from this requires specialized turbines that can produce enough energy in a small pipe.
Engineers from the PolyU’s Department of Building Services Engineering and the Water Supplies Department of the Hong Kong teamed up to create mini-turbines that can use Hong Kong’s 7800km long network of water pipes to produce energy to run all observation equipment. The small turbines are placed in pipes to harness the motion of water passing by. Each turbine is able to produce 80V, which is enough to power about four fluorescent light bulbs.
The system features a small hydroelectric generator which dips into the flowing water and features a central rotating shaft to minimize energy loss. To increase output, the team placed a block at the opening of the pipe to accelerate flow and hence produce more energy. The turbine too has been designed in a fashion that it doesn’t need any lubrication, which could adversely affect the quality of water. When fully installed, the array of turbines could save about 700kWh of electricity and reduce CO2 emissions by 560kg each year.