Sustainable energy supply.

Potential of biomass as sustainable energy supply
Biomass is a material that was recently living.(wood, plants animal waste)
Materials are burnt to release energy. It can be processes to produce biofuels
biofuels- to ferment sugarcane to produce alcohol.
It is a sustainable energy resource
Biomass is released by burning, which produces carbon dioxide. Biomass does not contribute to global warming as the amount of Co2 released equals the amount of co2 taken in. eg Brazils 18% transport fuel is from biomass.

Disadvantages- Large land is needed to produce sufficient amounts of bio fuels. Fossil fuels are often used to transport biomass.
Wood burning produces methane.

Solar power-Energy from the sun. It is a clean energy resource. Solar water heaters use the sun to heat water.
PV cells convert light energy into electrical energy. Which can be transported of used.

Disadvantages- Co2 released when equipment of produced.
PV cells are expensive.
Large areas of solar panels and sunny climate is needed.
It could generate 2.5% of the world energy by 2025.

Tidal energy- comes from the movement of tides. Tides can be harnessed by used tidal barrages which is dam built on a rivers estuary as the tide flows in water passes the gates of the barrage turning wind turbines that generate electricity. 

As the earth is covered i 71% water it would be ideal. Tidal energy has a high energy density.

Disadvantages- the cost for construction of a tidal power plant is very high. Creating dams is hard engineering method. These plants can only be build in coastal regions which means it is build far from where it is consumed so transportation is costly,

Wave energy- is harnessed using a wave generator.  Water enters the chamber the increased mass forces air in the chamber which turns the turbine.

Disadvantages- Waves are unreliable as there aren't always waves.
Generators are expensive.

HEP-
energy of falling. HEP supply about 20% of the worlds energy.
Once plants are build there release no green house gases.
At HEP large dams are build to trap large volumes of water. Tunnels containing turbines are built into the dams. The pressure of the water above drives water through the tunnels, turning the turbines.
Generators the covert the energy into electricity.

Disadvantages of HEP- Construction of dams means habitats and communities are destroyed.'
If dams fail then large areas of land will flood. Ecosystems ad fish migratory paths are disrupted  The plants are expensive to build making the release CO2.

The Nurek Dam in Tajikstan is the tallest dam in the world and has nine HEP turbines it supplies 98% of the countries electricity.

Wind energy- Harnessed by wind turbines. Wind turbines are built where there are regular winds. The energy turns the blades on the turbine converting wind energy into mechanical energy this is then converted into electrical energy by a generator.
Denmark produces 19.7% of its own wind energy.

Disadvantages- The amount of energy depends on wind strength.
Creates noise pollution. Turbines can kill birds.Large amount of land is needed to supply the demand. Less ascetically pleasing. Many turbines are needed for a sustainable amount of energy eg the largest turbine can only supply energy for 457 people.
You need 7000 wind turbines to create enough energy as a nuclear power plant.

Case study-Aberystwyth

›Cefn Crowyn in the hills above Aberystwyth – the coast – windy location

›Wales one of the windiest places in the World

›Wind farms can be onshore & offshore

›Wind is strongest in winter when energy is needed most

›Most powerful onshore wind farm in UK

›Cost £50 million – June 2005

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