POWER STATIONS THAT USE RENEWABLE ENERGY SOURCES

Some power stations use clean, renewable energy sources to produce electricity. These alternatives help to reduce our dependence on non-renewable sources of energy, such as fossil fuels, which also cause environement problems.

- Wind farms.
Use the kinetic energy of the wind to generate electricity. The wind turns the blades of a turbine, at the top of a tower. The blades are cennected to a gearbox which increases the rotational speed of the generator.
The output and efficiency depend on two factors:
· The location of the farm, which determines the speed and strength of the winds.
· The numbers of turbines that can be installed there.

- Hydroelectric power stations.

There are two types of hydroelectric power station.

· In conventional hydroelectric stations,the wáter flows from the reservoir to the turbines throungh a high-pressure conduit.Then it flows out,usually into a river.

·In pumped-storage hydroelectric stations,the water flows from the turbines to a second reservoir. Then it is pumped back up to the higher reservoir and stored for later.

-Solar power stations.

Use energy from sunlight to generate electricity.There are two main types of solar power stations:

· Solar thermal stations: with solar collectors that absorb sunlight in order to produce heat. With mirrors called heliostats that reflect and concéntrate sunlight in one place.

· Photovoltaic stations: solar panels convert sunlight directly into electricity. Small solar power installations can provide energy for homes and rural areas. Excess power can be stored in batteries or accumulators and used at night.

- Biomass power stations.

Biomass is an organic material that is produral processes.

In a biomass power station,the fuel used to produce energy comes from biomass. The steam produced from burning the biomass moves a turbine that is connected to a generator.

Biomass stations are efficient because they use waste materials that would normally end up in landfill sites.

- Marine power stations.

Use the movement of ocean water to generate electricity. There are three general types of marine power stations:

· Tidal power stations, which use the energy of tides.

· Wave power stations, which use the energy of waves.

· Ocean thermal conversion stations, which use the difference in water temperature between the surface of the ocean and deeper areas to produce energy.

- Geothermal power stations.

Use natural heat from the deepest underground layers of our planet. Can be used in two ways:

· It can be used directly to provide hot water for heating and industrial uses.

· It can be used indirectly to drive generators and produce electricity.