Water Power
Hydro-electric power
How it works:
a reservoir is built with a dam in it, a mass of water is held back by the damp and then suddenly released all at once, sending the water through a turbine at great force.
Advantages:
pollution free and safe when up and running
Disadvantages:
creating it there can he tremendous disruption and upset to the environment, animals and nearby residents.
finding sites large enough forthis is quite hard.
Tidal power
How it works:
by using the gravitational pull of the moon, which creates tidal rises and falls, to produce energy.
Advantages:
using natural forces (no additional fuel sources are needed)
in the long-term it could enable cheaper electricity.
once up and running, quite safe to the environment
a large-scale tidal power scheme on the River Ranee near St Maio in France helps produce a considerable amount of electricity; others in Russia, Canada and China have also been very productive and economical.
Disadvantages:
tidal power generators can be quite expensive to set-up -- the costs involved in building such a scheme would be quite high initially
the disruption to the area
the risk of pollution to the river
Wave power
How it works:
by capturing mass of kinetic energy created by waves
building dams or pipes for the water to go up
Advantages:
with waves which are around 400m long 700 kilowatts of electricity per metre could be captured
if a suitable site could be found, cheaper and environmentally friendly energy could be created
Disadvantages:
disruptive to other industry, such as fishing
Costs:
building dams or pipes can be quite expensive
cheaper energy
6. It is evident that every alternative to the traditional source of power and energy has its pros and contras. Read about the contradictions of another environmental project. Answer the questions using the information from the text as well as your background knowledge.
The Big Green Fuel Lie
George Bush says that ethanol will save the world. But there is evidence that biofuels may bring new problems for the planet
By Daniel Howden in Sao Paolo The issue
The ethanol boom is coming. The twin threats of climate change and energy security are creating an unprecedented thirst for alternative energy with ethanol leading the way.
That process is set to reach a landmark on Thursday when the US President, George Bush, arrives in Brazil to kick-start the creation of an international market for ethanol that could one day rival oil as a global commodity. But a growing number of economists, scientists and environmentalists are calling for a "time out" and warning that the headlong rush into massive ethanol production is creating more problems than it is solving.
Pros of ethanol
To its advocates, ethanol, which can be made from corn, barley, wheat, sugar cane or beet is a green panacea – clean-burning, renewable energy source that will see us switch from dwindling oil wells to boundless fields of crops to satisfy our energy needs.