Hydro Electricity – Renewable Energy Basics

Hydro electricity (which is sometimes spelt hydroelectricity) is a widely used form of renewable and environmentally friendly electricity generation that is low in emissions, uses no fossil fuels and creates little or no pollution.

Hydro electricity works on the same basic principle as the old water wheels and water mills used to use. Water flows over a flanged wheel and turns the wheel. The wheel is hitched to a generator and the rotation of the wheel induces a current in a magnetic coil. It sounds simple and it is. However, to be able to generate enough electricity, the water current has to flow fairly fast to make the turbine spin at sufficient speed.
What has been found to be the best way to produce hydro electricity on a large scale is to build a large dam on a suitable river and have strategically placed sluice gates that can be opened to allow the water to flow through – forced on by the weight of the water in the dam above it – at high speed, turning turbines on the way.

Disadvantages of Hydro electricity

Constructing a hydro electric dam does have some environmental and social costs:

• A river must be dammed, which means that a valley must be flooded. This may have an effect on erosion and may cause loss of habitat to local wildlife. Farmland may also be lost.
• Hydro electric dams need to have special slipways to prevent fish from being swept into the works and killed or injured (and damaging the turbines).
• Hydro dams can be large and unsightly. However, a creative solution to this was found when the Manapouri power station in New Zealand’s South Island was constructed in Fiordland National Park (this includes the famous Milford Sound and was the location for several scenes in the Lord of the Rings films). This hydro electricity station was constructed underground and mostly out of sight.
• Hydro electricity may not be a suitable solution for low-emission generation in areas with unreliable rainfall for obvious reasons.
• A lot of energy needs to go into the construction of the dam and turbines.
• The construction of Dams are expensive and take many years to complete.

Advantages of Hydro Electricity

Once they have been constructed, hydroelectricity dams are “clean” with no emissions or use of unsustainable resources. They also have some benefits for the environment and for people”:

• The water is a safe habitat for aquatic life and for wading birds
• The dam also provides a source of water for wildlife and farm animals in the surrounding area.
• The artificial lake created by the dam has some tourism spin-offs for the local community – boating and fishing in particular (sometimes, the outflow waters from the dam are warmer and fish thrive in them – Lake Tekapo (again in the South Island of New Zealand) produces some massive salmon near the dam outlet!) The lakes can also be used for fish farms.
• The power generated by this means is very clean and it produces no carbon emissions.

Overall, this is an effective medium for producing renewable energy but due to the reasons discussed above, such as the social, economic and environmental costs, it may be unfeasible for use in your town.

This hydro electricty dam generates renewable energy for neighbouring towns