Benefits and potential impacts of hydropower
This page gives examples of community benefits offered by the use of hydropower.There is also a list of the environmental benefits and impacts.
Benefits to the community of a hydropower plant
- It can reduce residents' energy costs and generate income through the Feed-in Tariffs.
- A hydropower installation can aid in the irrigation of nearby agricultural land.
- It can act as a flood management mechanism. It can reduce the risk of communities flooding downstream from the plant by controlling the flow of the river and suppressing river surges.
- It can be more predictable than other forms of renewable energy as outputs change gradually from day-to-day, as opposed to hour-by-hour.
- The power generated by hydropower broadly correlates with a community's energy demand. For example, the potential power output is greater in winter, when energy demands are greater, as levels of rainfall and river flows tend to be higher.
- It has a much longer lifespan than other renewable energy sources so it will continue to produce electricity without the need for substantial reinvestment.
- Small scale hydropower can contribute to a decentralised energy network.
- It could potentially offer additional leisure and recreational benefits, for example, an area for sailing on a reservoir behind a dam.
Impacts on the community of using hydropower
- It could have an effect on certain users of the watercourse, for example boat users, walkers and fisherman and so on.
- Visually, some residents may find hydropower plants objectionable.
- A large upfront investment is required to install hydropower.
- Small-scale hydropower, without a reservoir, is reliant on available river flow which can be unreliable.
- In the case of large scale hydropower, communities or individuals may have to be relocated to create a reservoir and the construction of a dam can result in a loss of cultural heritage.
Environmental benefits of using hydropower
- It does not directly produce CO2 emissions in the generation of electricity.
- It releases negligible quantities of sulphur and nitrogen oxides which are a component of acid rain.
- It does not produce any particles of chemical compounds such as dioxins which are harmful to human health.
- It does not deplete a natural resource in its operation.
There are some environmental impacts of using hydropower, particularly in the case of large-scale plants where dams are used. A dam could have the following effects:
- The reservoir behind a dam could reduce water supply downstream due to an increase in surface water evaporation.
- It could damage the surrounding environment during construction.
- It may prevent silt from being transported downstream which could potentially starve agricultural land of soil and nutrients during flooding events, calling for the costly use of fertilisers and irrigation systems.
- The construction of a dam will cause the valley upstream to permanently flood. Any vegetation that is submerged due to the rise in water level can decay anaerobically, producing methane, which has a higher global warming potential than CO2. In this case, the carbon dioxide savings achieved from moving away from fossil fuelled power plants would be offset.
- It could prevent fish from migrating past the dam, although in such instances a 'fish ladder' can be installed to enable fish to swim past the dam.
- The construction and operation of a dam will significantly alter landscape character, result in loss of habitats and create a new feature that may be out of character with the rest of the landscape.
- The dam could fail and cause devastating flooding downstream, regular maintenance and monitoring of the dam is necessary to minimise this risk.
1 May 2012