Renewable energy resources

Solar

Where is it from?

Energy from sunlight is captured in solar panels and converted into electricity.

Advantages

  • potentially infinite energy supply
  • single dwellings can have own electricity supply
  • maintenance and upkeep costs are low

Disadvantages

  • manufacture and implementation of solar panels can be costly
  • energy is only supplied during the daytime and when there is enough sun
  • energy can be stored but this is expensive
  • solar farms can take up large areas of land

Wind

Where is it from?

Wind turbines (modern windmills) turn wind energy into electricity.

Advantages

  • potentially infinite energy supply
  • versatile in terms of size and number of turbines
  • can supply energy to rural areas that are not connected to electricity grid

Disadvantages

  • manufacture and implementation of wind farms can be costly
  • some local people object to on-shore wind farms, arguing that it spoils the countryside
  • some argue windfarms are dangerous for birds and other wildlife
  • wind is an unreliable source of constant energy

Tidal

Where is it from?

Tidal energy comes from the movement of tides driving turbines. A tidal barrage (a kind of dam) is built across estuaries, forcing water through gaps.

In future underwater turbines may be possible out at sea and without dams.

Advantages

  • ideal for an island such as the UK
  • potential to generate a lot of energy
  • tidal barrage can double as a bridge, and help prevent flooding

Disadvantages

  • construction of barrage is very costly
  • only a few estuaries are suitable
  • opposed by some environmental groups as having a negative impact on wildlife
  • may reduce tidal flow and impede flow of sewage out to sea

Wave

Where is it from?

The movement of seawater in and out of a cavity on the shore compresses trapped air, driving a turbine.

Advantages

  • ideal for an island country
  • more likely to be small local operations, rather than done on a national scale

Disadvantages

  • construction can be costly
  • may be opposed by local or environmental groups.

Geothermal

Where is it from?

In volcanic regions it is possible to use the natural heat of the Earth.

Cold water is pumped under ground and comes out as steam. Steam can be used for heating or to power turbines creating electricity.

Advantages

  • potentially infinite energy supply
  • used successfully in some countries, such as New Zealand and Iceland

Disadvantages

  • can be expensive to set up and only works in areas of volcanic activity
  • geothermal and volcanic activity might calm down over time, leaving power stations redundant
  • dangerous elements found underground must be disposed of carefully

Hydroelectric Power (HEP)

Where is it from?

Energy harnessed from the movement of water through rivers, lakes and dams.

Advantages

  • creates water reserves as well as energy supplies
  • potentially a good option for countries with high rainfall
  • pumped storage can supply energy at peak times and then return water to storage using surplus energy when demand is low

Disadvantges

  • costly to build
  • can cause the flooding of surrounding communities and landscapes
  • dams have major ecological impacts on local hydrology
  • build up of plant and other material reduces storage over time

Biomass

Where is it from?

Biomass energy is generated from decaying plant or animal waste. It can also be an organic material which is burned to provide energy, eg heat, or electricity.

An example of biomass energy is oilseed rape (yellow flowers you see in the UK in summer), which produces oil. After treatment with chemicals it can be used as a fuel in diesel engines.

Advantages

  • a cheap and readily available source of energy
  • provides constant, reliable energy
  • if the crops are replaced, biomass can be a longterm, sustainable energy source

Disadvantages

  • when burned, it gives off atmospheric pollutants
  • contributes to build-up of greenhouse gases
  • if crops are not replanted, biomass is a non-renewable resource

Wood

Where is it from?

Wood is obtained from felling trees, burned to generate heat and light.

Advantages

  • a cheap and readily available source of energy
  • if the trees are replaced, wood burning can be a longterm, sustainable energy source

Disadvantges

  • when burned, it gives off atmospheric pollutants
  • contributes to build-up of greenhouse gases
  • if trees are not replanted, wood is a non-renewable resource

It is important to remember that biomass and wood are only renewable if the trees and crops are replanted. Some people fall into the trap of thinking that bio means renewable - it doesn't!

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