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