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7.4 Renewable Energy- Alternative Energy Sources (Geothermal…
7.4 Renewable Energy- Alternative Energy Sources
solar energy
solar thermal systems also known as concentrated solar power, use different methods to collect and concentrate solar energy to boil water and produce steam.
photovoltaic cells
advantages
no greenhouse or pollutants
no toxic materials
easy to use, low maintenance
disadvantages
low energy efficiency
wind power
wind power that the potential to produce 40 times the world's current use for electricity.
advantages
abundant, widely distributed, and inexhaustible
carbon and pollution free
fast and relatively cheap
increasing energy efficiency and reducing costs
disadvantages
needs backup or storage system when winds die down unless connected to a national electric grid
visual pollution for some people
low-level noise bothers some people
can kill birds if not properly designed and located
Geothermal
is heat stored in soil, underground rocks and fluids in the earth's mantle
the most energy efficient, reliable, environmentally clean, and cost-effective way to heat or cool space
advantages
medium net energy
low CO2 emissions
disadvantages
drilling geothermal wells is expensive and risky
can be nonrenewable if heat is extracted faster than can be restored
not many hydrothermal sites with concentrations of heat high enough to make it affordable
biomass
energy can be produced by solid biomass or organic matter or converting it to gaseous or liquid biofuels
the two most common liquid biofuels are: ethanol and biodiesel
solid biomass
advantages
widely available in some areas
moderate costs
medium net energy
disadvantages
contributes to deforestation
can open ecosystems to invasive species
increases C02 emissions
liquid biofuels
advantages
reduced C02 emissions
medium net energy for biodiesel
medium net energy for ethanol
disadvantages
fuel crops can be invasive species
low net energy for corn ethanol and biodiesel from soybean
higher CO2 emissions for corn ethanol
biodigesters- biogas
fed by organic material, broken down by bacteria to produce biogas and other solids used as fertilizers
advantages
reduces amount of waste going to landfields
helps to get rid of and make use of food waste, plant waste
creates less C02
creates jobs
disadvantages
too low net energy for mass scale
impurities can damage if used in combustion energy
hydropower
any technology that uses the kinetic energy of flowing and falling water to produce electricity.
advantages
least expensive renewable energy resource
disadvantages
reservoirs fill with silt and become useless
flood and destroy terrestrial habitat upstream.
hydrogen
advantages
no CO2 emissions or air pollutants
more efficient
little maintenence
disadvantages
expensive
dangerous to store and transport