Hüdroenergia - ettekanne (1)

Hello
My name is JOHN SMITH and I am here to talk about Hydroelectricity.
Global energy use has risen by 70% since 1971 and continues to increase at the rate of 2% per year . There are many scenarios for future demand . One solution would be to use more hydropower . In 2005, renewable energy represented one-fifth of total power generation.  Hydropower is the most advanced of the renewable and represents 87% of this production . 160 countries all over the world are using hydropower. Five countries make up more than half of the world’s hydropower production. Those countries are: Brazil ,Canada, China , Russia and the USA.
(Production)
*Most of the energy comes from the potential energy of dammed water driving a water turbine and generator . In this case the energy extracted from the water depends on the volume and on the difference in height between the source and the water’s outflow.
*Pumped storage hydroelectricity produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the reservoir. And when there is a big demand, like in the evenings, then the water is released and flows through the turbines .
there are many Advantages for hydropower.
*The mayor advantage of hydroelectricity is eliminating the cost of fuel. You don’t have to fear about the increasing cost of fossil fuels like oil and natural gas.
*The second advantage is that hydroelectric plants last longer than fuel-fired plants. Some hydro plants have been operational about 100 years .
*Operating labor costs are low as well because the plants are automated.
*And Because the hydroelectric dams do not burn fossil fuels, they do not directly produce carbon dioxide.
*The reservoirs can also provide facilities for water sports, and become tourist attractions themselves. In many countries farming fish in the reservoir is common. Also large dams can control floods. The reservoirs can also improve transport.
on the other hand there are some Disadvantages
*Hydroelectric projects can be disruptive to surrounding ecosystems both upstream and downstream. For instance , studies have shown that dams along the Atlantic and Pacific coasts on North America have reduced salmon populations, even thou most dams have fish ladders installed.
* Another disadvantage of hydroelectric dams is the need to relocate the people living where the reservoirs are planned. Additionally, historically and culturally importants sites can be flooded and lost .
*Dams can be vulnerable to bombardment during wartime, sabotage and terrorism .
I would like to conclude by saying that the hydro energy is the simplest and most known renewable energy there is. It is perfect for balancing the energy system and for supplying power at peak times of the day. And it does not create greenhouse gasses.
Thank you for listening . If you have any questions then you may ask them .