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, no sun means a need for a “battery”

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: Cons: 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 Pros: Important for places that can use it, predictable, 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 developed

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