Tuesday, September 29, 2009

Hydroelectricity Dam or Hydroelectricity Power Station

Dam Hydroelectricity Description


Area of Dam Hydroelectricity Station


Align Center
Dam Hydroelectricity Major Components


Dam Hydroelectricity Picture

How the Dam hydroelectric works? The water is held in a reservoir as per picture above (Dam Hydroelectricity), behind the dam, the water close to the control gates is where the intake is, and when the control gates open, the water rushes through the penstock and turns the turbine. After the water does so, it goes through the outflow into the river. The turbine spins the generator, and the electricity goes to the transformer in the powerhouse. Then the transformer transforms the electricity into a usable form, and the electricity travels through the power lines and goes to homes and businesses.

One more thing that is needed is location. To build a dam there has to be valleys and rivers. This will help with the building of the dam. There has to be great location or it won’t work. The land cannot be flat, or there is no way to build a dam. Canada, USA, the former USSR, Brazil, China, Norway, Japan, Sweden, India, and France all use hydroelectric energy. These countries are in order from the largest number of kilowatts in billions that are used each year.

There are advantages and disadvantages of using hydroelectricity energy. Here are some of the advantages. It is renewable, clean, non-polluting, and it prevents floods. Not all dams produce electricity, but they prevent flooding, and others do both.

As said, there are advantages of using hydroelectricity energy. There are disadvantages too. Here are some of the disadvantages. Hydroelectricity dams can harm many species that live on the area, the land around the dam can be destroyed, and the furious turbines will kill the fish.

As said before, dam hydroelectricity energy is one of many sources of electricity in the world. The future of hydroelectricity power is looking like it will still be used in the next century or more, because the world will still have plenty of running water and the need for lots of non-polluting energy.

Source: Hydroelectric Energy



Monday, September 21, 2009

How a Coal-fired Power Plant works

Coal Fired Power Plant Process

1. Coal Supply

  • Coal from the mine is delivered to the coal hopper, where it is crushed to five centimetres (2 inches) in size.
  • The coal is processed and delivered by a conveyor belt to the generating plant.

2. Pulverizer

  • The coal is then pulverized, or crushed, to a fine powder, mixed with air and blown into the boiler, or furnace for combustion.

3. Boiler

  • The coal / air mixture ignites instantly in the boiler.
  • Millions of litres of purified water are pumped through tubes inside the boiler.
  • Intense heat from the burning coal turns the purified water in the boiler tubes into steam, which spins the turbine (see number four) to create electricity.

4. Precipitator, stack

  • Burning coal produces carbon dioxide (CO2), sulphur dioxide (SO2) and nitrogen oxides (NOx).
  • These gases are vented from the boiler.
  • Bottom ash, which is made of coarse fragments that fall to the bottom of the boiler, is removed.
  • Fly ash, which is very light, exits the boiler along with the hot gases.
  • An electrostatic precipitator (a huge air filter) removes 99.4 per cent of fly ash before the flue gases are dispersed into the atmosphere.

5. Turbine, generator

  • Water in the boiler tubes picks up heat from the boiler and turns into steam.
  • The high-pressure steam from the boiler passes into the turbine (a massive drum with thousands of propeller blades).
  • Once the steam hits the turbine blades, it causes the turbine to spin rapidly.
  • The spinning turbine causes a shaft to turn inside the generator, creating an electric current.

6. Condensers and the cooling water system

  • Cooling water is drawn into the plant and circulated through condensers, which cools steam discharged from the turbine.
  • Steam from the turbine also passes through the condensers in separate pipes from cooling water.
  • The cold water is warmed by the steam, which condenses back into pure water and circulates back to the boiler to begin the process of generating electricity again.
  • Cooling water, now warm from the heat exchange in the condensers, is released from the plant.

7. Water treatment plant: water purification

  • To reduce corrosion, water must be purified for use in the boiler tubes.
  • Other wastewater systems within the plant collect water used to clean pipes and other equipment, and sludge from the water purification process and other processes.
  • Waste water is pumped out of the plant and into the holding ponds.

8. Precipitator, Ash systems

  • Ash that builds up on the precipitator's plates is vibrated off and collected in large hoppers or bins.
  • Fly ash and bottom ash are removed from the plants and hauled to disposal sites or ash lagoons.
  • Depending on the market demand, fly ash produced from TransAlta's three plants is sold to the cement industry for construction.

9. Substation, transformer, transmission lines

  • Once the electricity is generated, transformers increase the voltage so it can be carried across the transmission lines.
  • Once electricity is delivered to substations in cities and towns, the voltage flowing into the distribution lines is reduced, and then reduced again to distribute electricity to customers.
Source: canadiancleanpowercoalition
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