Ch 18 Renewable resources Renewable energy energy from

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/vid eo/examples/howsolar-panelswork. html http: //videos. howstuffworks. com/science-channel/5015 invention-nation-solarpanels-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 k. W power system $10, 000 – $15, 000 – 2 k. W power system $16, 000 - $20, 000 – 5 k. W 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: – 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 – 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 • Heat pump = $3, 500 - $7, 500 • 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