What is run-of-river
It is a design scheme for hydropower generation that is least disruptive to the environment. The scheme works by redirecting river water through a weir into conveyance pipes towards a penstock and feeding it downhill to the power station.
How it works:
A portion of the water from the upper reaches of a river is diverted into a pipeline through an intake weir. This pipeline brings water to a forebay tank where the water flow is slowed down allowing sand and other particles to settle. From the forebay, clear water passes through a pressure pipe or penstock to the turbine. The natural force of gravity generates energy used to spin the turbine which is enclosed in a powerhouse together with the generator and control equipment. The spinning turbine enables the generator to produce electricity. From the turbine, the water is discharged down a tailrace or canal back into the river.
Do run-of-river hydroelectric projects use dams?
Instead of dams, run-0f-river projects use a diversion weir to move the water towards the intake. There are no large dams constructed to store water.
What is a weir?
A weir allows water to continue flowing and is subject to flow changes from the natural behavior of the river from rains. It therefore maintains a more seasonal pattern of flows than a dam and reservoir system. The amount of electricity produced by a run-of-river project depends on the amount of water available in a river.
What are the advantages of run-of-river of hydropower plants?
Compared to conventional power plants and other renewable energy resources, run-of-river hydro projects have the following advantages:
- ROR hydro is a time-tested and proven technology;
- ROR as decentralized power generation facility benefits rural electrification; built in small units near the load centers, ROR can reduce investment for transmission lines and the power losses associated with long transmission lines;
- ROR does not create social and environmental problems often associated with large-scale hydropower development.
- ROR saves on foreign exchange and reduces CO2 emissions associated with fossil fuels;
- ROR can be incorporated in other water use projects such as irrigation, water supply, flood control, recreation and tourism;
- ROR improves watershed management.
What is renewable energy?
Renewable energy comes from natural resources such as sunlight, wind, rain, tides or geothermal heat which are naturally replenished, unlike fossil fuels, which, once extracted are not replenished.
Why are run-of-river projects called clean energy?
Sometimes called clean energy, run-of-river projects are sustainable and clean. Unlike fossil fuels, river water is naturally replenished by rain. Further, run-of-river projects do not cause pollution or greenhouse gas emissions. Run-of-river projects have a lower environmental impact because water is allowed to flow naturally. Likewise, the construction of projects has low impact on the environment.
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Cleanergy is our response to the need to develop energy technologies that have little or no adverse effects on the environment, and to use sources that are locally available and constantly replenished like water. Water is our main input to generate energy as it is a renewable resource.
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