Renewable Energies

fossil fuels and renewable energies

depends on

• power of wind
• amount of wind towers
• size of propellers

best areas

• coastal areas
• on top of rounded hills
• open plains
• gaps in mountains

advantages:

• wind is free
• they don’t produce waste or greenhouse gases
• the land beneath can be used for farming

disadvantages:

• wind isn’t predictable
• the land where the best circumstances are, is often quite expensive (near the coast)
• it is unsightly
• it may be close to a migratory route, so birds can die
• the television reception nearby can be affected
• noisy

disadvantages:

• very expensive
• the dam causes flooded areas, animals get problems
• great and negative impacts for animals and residents
• water quality and quantity downstream can be affected, which can have an impact on the plant life

wave power

advantages:

• potential to generate a huge amount of energy
• not very expensive
• clean energy

disadvantages:

• not precisely calculable
• the units need to be very durable

advantages

• clean and free energy
• calculable
• not very expensive
• no large impact on the environment

pumped storage reservoirs

unerenewable energies: gained from finite resources

renewable energies: gained from infinite resources

fossil fuels

oceanic energy and storage

origins

tidal power

swanturbines

tidal reef

barrages

methods of harnessing waves:

Fossil Fuels are formed by natural processes such as decomposition of buried dead organisms.

the waves make the tubes bob up and down

disadvantages

• barrages are very expensive and have a big effect on the environment
• the tide provides energy only 10 hours a day

the bending hinges pump hydraulic fluid which drives generators

wind power

environmental effects

Burning of fossil fuels produces air pollutants such as carbon dioxide and heavy metals.

These emissions cause acid rain and boost the global warming.

Also the harvesting process creates environmental concerns

• one of the most common ways to store energy
• needed to provide constant energy supply

advantages

• no pollution is caused
• can be integrated in the landscape

disadvantages

• very expensive

reserves

As it takes fossil fuels million of years to form, their amount on eart is limited.

At a constant consumption they would last:

Coal: 148 years

Oil: 43 years

Natural gas: 61 years

biofuels

hydroelectric power

biomass

ganing energy from organic material

Solar energy

it is made use of the gravity force

solid waste

sugar cane

Solar Cells - photovoltaic

Convert solar radiation into direct current electricity

bioconversion

biofuels

Concentrated solar power

A system of lenses and mirrors focus a large area of sunlight into a small beam.

gravitational potential energy

electricity

Solar towers

A big greenhouse with a tall tower in the middle. The hot air rises up the tower and drives turbines.

disadvantages:

• large quantities needed
• greenhouse gases
• seasonal

advantages:

• it makes sense to use waste materials where we can
• cheap
• less fossil fuels

Disadvantages

• Doesn't work at night.

• Very expensive to build solar power stations, although the cost is coming down as technology improves.

• Can be unreliable unless you're in a very sunny climate.

biogas

biodiesel & bioethanol

Advantages

•Solar energy is free

•In sunny countries, solar power can be used where there is no easy way to get electricity to a remote place.

•Handy for low-power uses such as solar powered garden lights and battery chargers, or for helping your home energy bills.

mixture of methane & hydrogen

main sources:

• crops and palm oil -> biodiesel
• algae -> bioethanol

advantages:

• the water/energy is free
• no wast or pollution
• very reliable
• can increase to full power quite quickly
• constantly generation of electricity is possible

manure, sewage "green waste" -> methane and carbon dioxide

wood or other biomass -> "wood gas"

potentially carbon-neutral

usable for vehicles / at home

advantage:

• preventing methane from escaping into the atmosphere

advantage:

• closer to being carbon neutral

disadvantage:

• space needed