7. Enviromental impact

Power stations have an important impact on local ecosystems. Power stations also generate waste products taht can affect the environment.

7.1. Environmental impact assessment.

TIPE OF POWER STATION       ENVIROMENTAL IMPACT        ENERGY USED  
        Wind                                          It is non-polluting, but it has                   Renewable
                                                          visual and acoustic impacts.


    Hydroelectric                                It has a major impact because                  Renewable
                                                          it changes the flow of rivers
                                                          and floods large areas.

   
     Solar                                             It is non-polluting, but large                    Renewable
                                                          power stations take up a lot
                                                          of land.


    Marine                                         The construction of marine                        Renewable
                                                         stations affects the local enviroment.


    Biomass                                       The technology is beneficial when it         Renewable
                                                         used properly.


    Fossil fuels                                   Ir pollution contributes to climate              Non-renewable
                                                         change. Water is also polluted when
                                                         it is used for cooling.            


    Nuclear                                        Radiation is very dangerous if there are      Non-renewable
                                                        accidents. The waste products are not
                                                        recyclable.




7.2. Effects on the enviroment.
Energy production includes many steps, from the extraction of natural resources to the transportation and final distribution of energy to consumers. Each of these steps can have an impact on the enviroment.

Extracting natural resources.
Fossil fuels and radioactive elements, such us uranium, must be extracted from underground deposits. When those deposits are exhausted, we must find new ones to replace them.

Transporting fuel.
Most oil transported over land through gas pipelines and by sea in large ships called oil tankers. Natural gas in transported over land through gas pipelines or by sea in tankers as liquid natural gas (LNG). These tankers are called LNG carries. Natural disasters and accidents can also affect gas pipelines and LNG carries.

Generating electricity.
Hydroelectric power stations require large amounts of water which must be stored behind dams in reservoirs. These reservoirs flood large areas of land and change the natural flow of the river. These changes have enormous effects on ecosystems along the entire length of the river.

Waste treatment.
Power stations that use non-renewable sources of energy produce large amounts of waste. However, some steps can be taken to reduce waste and its effects.

• Filters can reduce pollutants, such us nitrous oxide and sulphur.
• Low-sulphur coal can also be used to reduce sulphur emissions.
• Large forests should be protected because they remove CO2 from the air.

Near waste is kept in special conntainers with tick walls that block radiation. These containers are stored in nuclear graveyards, which are usually located underground or in deep ocean trenches.

7.3 Climate change.

Most of our electricity comes from power stations that use non-renewable energy sources. The situation has negative effects on the enviroment, and the most serious is climate change -a problem that is associated specifically with fossil fuels.

• When we burn fossil fuels, gases and methane are released into the air. The gases contribute to the greenhouse effect which increases the Earth's average temperature.
• Already we can observe some of the effects of global warning.
• Power stations that burn fossil fuels also release other pollution into the air. These pollutants combine with water vapour in the air to produce acid rain, which damges our forests.
• These power stations affect plant and animal life because they use refrigeration systems that pump hot water into our rivers and ocean. This increases the local water temperature and also reduces the amount of oxygen in the water.

7.4. Energy consumption.

The fossil fuels that consumers use in their cars on home heating systems also have an affect on the enviroment. In fact, they generate  the same types of air pollution a conventional thermal power stations: CO2, methane, nitrous oxide, sulphur oxide and heavy metals.