FOSSIL FUELS VS RENEWABLE ENERGY SOLAR ENERGY Direct
FOSSIL FUELS VS. RENEWABLE ENERGY
SOLAR ENERGY � Direct use of the sun’s rays to supply heat or electricity � Solar collectors: Box that heats either air or water and that is used to heat (80% of Israel’s homes) � Focus mirrors on a central object to heat water to provide electricity � Solar panels or photovoltaic cells Convert suns energy directly into electricity � Pros: Fuel is “free”& its nonpolluting � Cons: Necessary equipment and installation can be costly,
WIND ENERGY � Turbines convert the kinetic energy in the wind into mechanical power while a generator converts it into electricity. � Winds in North and South Dakota could provide 80% of the electrical energy used in the US � Some experts estimate that in the next 50 to 60 years, wind power could meet between 5 and 10 percent of the country’s demand
� Pros: � Clean � Cost-effective � Creates jobs � Can be put on existing farms/ranches � Cons: � Need technical advances � Noise pollution � Cost of large tracts of land � NIMBY � Animal “danger”
HYDROELECTRIC POWER � Power that is generated by falling water that drives turbines to produce electricity � Hydroelectric power produces about 5% of the US’s power � The water held in a reservoir behind a dam is a form of stored energy that can be released through the dam to produce electric power. � Pros: Domestic, quick output, reservoirs can be used for recreational activities
� Cons: � Rivers deposit sediment behind the dam (50 to 300 years) once it’s filled it no longer generates power � Availability of suitable sites (height to drop and flow rate) � Destroys habitat � Thermal pollution and shallowness downstream
GEOTHERMAL ENERGY � Harnessed by tapping natural underground reservoirs of steam and hot water Hot water is used directly for heating and to turn turbines to generate electric power � Reservoirs of steam and hot water occur where subsurface temperatures are high due to relatively recent volcanic activity. � � Pros: Good for small houses, no cost fluctuations, not weather dependent, minimal land space
� Cons: � Earth shifts so areas with hot water may not always be there � Hot water may be laced with minerals and salts and can corrode pipes and pollute the air
TIDAL POWER � Tidal power is harnessed by constructing a dam across the mouth of a body of water in coastal areas with a large tidal range. � The strong in and out flow that results drives turbines and electric generators. � Pros: Important for places that can use it, predictable, � Cons: not economical if the tidal range is less than 8 meters or if it’s narrow, not
HOW DO WE MOVE TOWARDS RENEWABLES � Legislation Kyoto Protocol – set limits on carbon outputs � Subsidies and incentives � Carbon Tax � Make technology available and costly for everyone including third world countries � Many studies show that developed countries can increase energy efficiency by 30% with little to no net cost
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