Centaalternative energy

• Solar energy is a renewable resource.

• No carbon dioxide emissions to add to the Greenhouse Effect

• No sulphur dioxide emissions to cause acid rain.

Solar powered station, California

• Solar panels can be quickly set up in remote areas

• Local communities can benefit from small scale use of solar power.

• Can be used to charge batteries to provide electricity when needed.

Solar cells used to charge batteries

to charge = caricare

• The initial cost of solar cells can be very high.

• The output is dependent on weather conditions and the time of day.

• Solar energy doesn’t work at night.

Solar reflector used for cooking

Output = resa, produzione

Wind in the pastWind in the past We have used wind We have used wind

power for thousands of power for thousands of years but during the years but during the past 250 years steam past 250 years steam engines, petrol engines engines, petrol engines and electricity took over and electricity took over from wind.from wind.

Wind ForeverWind Forever Wind is a renewable Wind is a renewable

energy resource. It is a energy resource. It is a regular part of our regular part of our weather, which is driven weather, which is driven by energy from the sun. by energy from the sun. So as long as the sun So as long as the sun keeps shining the wind keeps shining the wind will keep blowing.will keep blowing.

Advantages DisavantagesAdvantages Disavantages Renewable- as long Renewable- as long

as the sun shines the as the sun shines the wind will blowwind will blow

Clean source- no Clean source- no emissions of CO2, emissions of CO2, SO2 and N0x SO2 and N0x

Government Government initiatives to promote initiatives to promote wind powerwind power

The wind is not The wind is not always predictable – always predictable – some days have no some days have no wind.wind.

Suitable areas for Suitable areas for wind are often near wind are often near the coast, where the coast, where land is expensive.land is expensive.

How ?How ? The kinetic energy of the The kinetic energy of the

wind is converted into wind is converted into rotational kinetic energy rotational kinetic energy of the turbine.of the turbine.

The turbine drives the The turbine drives the generator. The generator generator. The generator converts the kinetic converts the kinetic energy into electrical energy into electrical energyenergy

In strong winds the In strong winds the blades of the turbine twist blades of the turbine twist slightly. This slows the slightly. This slows the turbine down and turbine down and prevents damage.prevents damage. slightly = lievementeslightly = lievemente

Wind Farm, Palm Springs, California

Wind Farm, Palm Springs , Canary Islands

Wind Farm, Tenerife, Canary Islands

• Water in a high reservoir has potential energy

• The water is allowed to fall under gravity• The water gains kinetic energy• The kinetic energy drives the turbines• The turbines drives the generators• The kinetic energy of the shafts of the

generators is converted into electrical energy

• There is no air pollution

• It is very reliable• Minimal running cost• No fuel needed.• There is an

immediate response

• You have to flood a valley to build a big dam

• there is a big impact on the environment

• possible loss of habitat for some species

• initial costs are high

• an eyesore (= un pugno nell’occhio).

• http://www.wikipedia.org/

• http://www.netpilot.ca/aes/index.html

• http://www.thegreenguide.com/

• http://science.nationalgeographic.com/science/environment.html