Ch. 18 Renewable resources!!

Renewable energy – energy from sources that are constantly being formed Solar - sun Hydroelectric – moving water Wind Biomass – organic material Geothermal – Earth’s heat Tidal - waves

Solar Energy - energy from the sun Nuclear Fusion creates energy on the sun Only a fraction of this reached the Earth But, this is enough to power: The wind (wind power) Plant growth (biomass) The water cycle (hydroelectricity) Nearly all renewable energy sources come from the sun!!!

Passive Solar – using the sun to heat something directly (ex: through windows)

Active Solar – collecting the suns energy to heat buildings or water (ex: solar cells or panels) Energy production from solar has doubled every 4 years since 1985!! http://solarsc.net/video/examples/how-solar-panels-work.html http://videos.howstuffworks.com/science-channel/5015-invention-nation-solar-panels-video.htm

Costs of Solar Energy All costs are up front costs, then savings follow Solar pool heater - $3000 - $4000 Home solar water heater $1000 - $3500 (includes installation) 1 kW power system $10,000 – $15,000 2 kW power system $16,000 - $20,000 5 kW power system $35,000 - $45,000 (will power most homes) You can get federal tax credits up to $2000 and some state tax credits as well

Wind Power Heat from the sun does not warm the earth evenly, causing the flow of air masses = wind Fastest growing energy source Cost is decreasing

Wind Farms Farmers can sell excess energy back to their local utility!! The windiest places on Earth could generate 10 times more energy needed on earth!! Problem: Transporting the energy from rural areas to where it is needed

Biomass Power - any organic matter that is used as an energy source Plants material, manure, methane, alcohol Major source of energy in developing countries! Problems: cutting too many trees can cause severe environmental problems Burning can release large amounts of air pollution

Methane – a byproduct of decomposition Britain’s first Dung-Fired Power plant using the methane released from cow manure for energy US uses some energy from methane produced from landfills!

Ethanol Produced from biomass! Benefits: Cons: Renewable Less emissions Cons: Takes lots of land Rise in produce prices

Hydroelectricity – energy produced by moving water 20% of the worlds electricity Leading Countries Canada US Brazil China Russia Norway

Hydroelectric Energy Benefits Disadvantages Inexpensive to operate No air pollution Last longer than fossil fuel plants Flood control recreation Disadvantages Changes a rivers flow Reservoir floods the area Displaces people Reduces water flow Destroys salmon fisheries Dam failure Sedimentation Today: the era of large dam construction is most likely over We are now using micro-hydropower

Geothermal Energy – energy from heat in the earth’s crust US is the worlds largest producer of geothermal energy

Costs of Geothermal Heat Pumps Drilling/installation = $10,000 - $25,000 You can get federal tax credits up to $2000 and some state tax credits

Alternative Energy – energy sources that are still in development How to get off the alternative list? Prove it is cost effective Environmental effects must be acceptable Current Alternative energy sources Tidal Power Ocean Ocean Thermal Energy Conversion (OTEC) Hydrogen

Tidal Power Tides – the movement of water caused by gravitational attractions between the sun, Earth and the moon. Currently used in France Russia Canada Cost is high and not many places suitable enough

Ocean Thermal Energy Conversion Warm ocean surface temperatures and cold subsurface temperatures are used to create electricity Surface temps boil water making steam…. Cold subsurface water cools the steam Problems Pumping water costs too much Pumping cold water to the surface could cause problems

Hydrogen?? The most abundant element in the universe! Burning it produces water vapor – not pollution Electricity is used to split water molecules to get hydrogen gas Challenges: Takes a lot of energy to make Not safe to store

Fuel Cells Combining Hydrogen and Oxygen produces electricity and its byproduct is water! No Emissions!!

Energy Efficiency - % of energy put into a system that does useful work Ex: a light bulbs light output not its heat energy More than 40% of energy produced in the US is wasted!! How to improve Public transport More efficient engines, i.e. fuel cells

Hybrid Cars Less emissions Small efficient gas engine Electric motor Convert breaking energy into electricity Aerodynamic Lightweight material

Cogeneration Using the same fuel source for two forms of energy Ex: wasted heat from a furnace can be used to produce electricity

Energy Conservation – saving energy by reducing use and waste How can we do this in our lives???

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