Sustainable Energy

Wind turbines

1- open and exposed areas with high chance of strong regular winds 

2- Wind turns blades, converts wind energy to mechanical energy to electrical energy

3- Large scale wind power = wind farms. Goes to an electrical grid to transport energy. Can be onshore or offshore 

4- Small scale can be connected to a grid but only supply one building 

EG- DENMARK 

Since 1970s. Families offered tax exemptions for generating own electricity. By 2004 over 150000 households had joined this scheme. 19.7% of energy produced by wind. 

DISADVANTAGES 

• wind is unpredictable = unreliable
• kill and injure birds 
• mostly sites of natural beauty 
• make lots of noise 

1- Biomass is material that is or was recently living (wood, plants, animals) and it burnt to release energy.

2- Can be processed to produce biofuels -> burnt to release energy

3- Eg - Producing biofuel by fermenting sugar cane to produce alcohol -> burn.

        - Methane and biogas are also types of biofuel produced by fermentation. 

4- Dont need a lot of technology so can be used in many different countries 

EG - BRAZIL - ETHANOL FUEL PROGRAME - SINCE 1970s

Ethanol is created by fermenting sugar cane. Supplies 18% of transport fuel. Decreased Brazil's oil dependance 

DISADVANTAGES 

• Fossil fuels used to transport and process biomass 
• Need land to create it -> lack of farm land -> food shortages 
• Its only renewable if carefully managed 

1- Solar water heaters use solar energy to heat water

2- Solar cookers work by concentrating sunlight -> heat energy -> trap for cooking 

3- PV cells convert light energy into electrical energy (home or exported to a grid) 

4- Materials that absorb the sun's heat during the day and release it at night to keep houses warm 

EG- RIZHAO, CHINA

99% of buildings have solar water heaters, over 6000 households use solar cookers and most traffic lights/street lights are powered by PV cells 

DISADVANTAGES 

• CO2 released in equipment production 
• PV cells are expensive 
• Large areas of solar panels and sunny climates are needed to produce a lot.

1- Movement of tides. Less variable than wind etc as they are regular, unchangeable events. Harnessed by tidal barrages and tidal stream systems 

2- Tidal barrages are built across estuaries. As the tide moves in and out the turbine is turned = generates electricity 

3- Tidal streams are fast flowing currents caused by the tide -> generators are put the their way to produce electricity 

EG- RANCE ESTURY, FRANCE, 1967

Largest one in the world, produces 19 000 hommes of electricity 

DISADVANTAGES 

• very expensive 
• disrupt wildlife and aquatic ecosystems 

1- Harnessed by using a wave generator - a chamber with a hole at the top that contains a turbine 

2- Wave flows into bottom of the chamber -> increased mass of water forces air in the chamber upwards -> turns turbine 

3- Turbine connected to generator that produces electricity 

EG-LIMPET, SCOTLAND, 2000

World's first device that used wave energy on a commercial scale. Generates electricity to the national grid.  

DISADVANTAGES 

• Wave energy is changeable -> unreliable 
• Generators are expensive
• Production released CO2 

Supplies 20% of world's energy + 60% of all electricity from renewables. 

Once built -> RELEASE NO GREENHOUSE GASES 

1- Dams built to trap large volumes of water - tunnels have turbines in them 

2- Pressure of water above drives water through turbines 

3- Generators then convert this energy into electricity 

EG- THE NUREK DAM, TAJIKISTAN

Tallest dam in the world + has nine hydroelectric turbines. In 1994 it generated 98% of the countries electricity 

DISADVANTAGES 

• reservoirs -> destruction to communities and habitats 
• if dam fails = catastrophic flooding 
• fish migratory paths are disrupted