Warm up How do you think renewable energy is different than nonrenewable energy?

Renewable Energy SEV4 Resource allocation and use

Renewable Energy ● Sources that are constantly being formed o Solar o Wind o Moving water o Earth’s heat

Solar Energy ● Already used o Water cycle o Photosynthesis o Wind o Sunshine warming a room o Solar cells

Passive Solar Heating (no moving parts) ● Use sun to heat something directly ● Northern hemisphere homes o Large, south facing windows absorb heat in winter o Overhangs block sunlight in the summer o Insulation and air flow are important

Active Solar Heating (moving parts) ●Sun’s energy is gathered to heat a building or water o Solar water heaters  Water heated on roof  Hot water used to heat water supply

Solar Panels ●Photovoltaic cells o No moving parts, no pollution (PRO) o Need many cells to produce decent yields (CON)

Wind Power ● Air is heated unevenly --> wind ● Wind power --> Electrical energy ● Fast growing resource ● 3 months to build a windmill

Wind Farms ● 280,000 homes in CA powered by wind ● Take up little space o Farmers add windmills to farm o Sell power to cities

Currently Underused ● Windiest areas on earth could generate 10x energy used worldwide. ● Transportation of energy is challenging ● Wind farms may make hydrogen from water in the future. Hydrogen used as fuel.

Biomass ● Plant material, manure, other organic matter used as fuel ● Challenges o Trees – renewable, but must be managed o Burning wood or manure – air pollution

Methane ● Decomposition --> methane (CH 4 ) ● Can be burned for heat or electricity o China – 6 million homes use methane for heating/cooking o England – Methane from cow manure as fuel for electricity o USA – electricity from methane generated by landfills

Alcohol ● Ethanol – fermenting fruit or agricultural waste ● Gasohol o mix of gasoline and ethanol o Produces less pollution when burned ● Requires more fossil fuel input than it yields

Hydroelectricity ● Produced from moving water ● 20% of world’s electricity ● How it works o Reservoir holds water o Water turns turbines/generator o Generator turns movement into electricity

Benefits of Hydroelectricity ● Expensive to build but cheap to operate ● No air pollution ● Last longer ● Flood control ● Water for drinking, agriculture, industry, and recreation

Disadvantages of Hydroelectricity ● Disrupts river flow o Ecosystems flooded behind dam o River flow diminished below dam ● Displaces people ● Farmland downstream less productive ● Decay in reservoir --> greenhouse gases

Modern Hydroelectricity ● No new dams in the USA ● Brazil, India, and China still building large dams ● Micro-hydropower

Geothermal Energy ● From the heat in earth’s crust ● Use water or steam to turn turbines ● The Geysers in CA powers 1.7 million homes ● Philippines, Iceland, New Zealand, Japan, Mexico, and Italy ● Renewable, but must be managed

Geothermal Heat Pumps ● Heat and cool homes ● Temp underground is constant ● Loop of fluid in a pipe underground and into house

Warm up ● What is the difference between renewable energy and alternative energy?

Alternative energy ● Still in development ● Some renewable energy was once alternative energy. ● Gov’t investments are vital to development.

Tidal power ● Benefits o Tides happen 2x a day o Generates electricity like hydroelectric dams ● Drawbacks o Expensive o Few suitable locations

Ocean Thermal Energy Conversion (OTEC) ● Benefits o Cold and warm ocean water are available at different depths o Cold water boils at low temp in vacuum chamber o Steam can turn a turbine ● Drawbacks o Not cost effective o Uses 1/3 of the energy it produces o Environmental effects unknown

Hydrogen ● Benefits o Abundant o No air pollutants when burned o (plants may produce it) ● Drawbacks o Generating it uses energy, money, and makes pollution o Explosive and dangerous

Fuel Cells ● Produce electricity chemically ● Combine H 2 and O 2 and electricity is produced. ● Water is only byproduct

Energy Efficiency ● What you get out vs. what you put in ● %Energy efficiency = ● Much energy is wasted Useful energy out Energy in x 100

Efficient Transportation ● Public transportation ● Hybrid cars o Efficient gasoline engine o Electric engine o Aerodynamic

Cogeneration ● Production of 2 useful forms of energy from 1 fuel source ● Use waste heat from a furnace to turn a turbine

Energy Conservation ● Saving energy o Use energy efficient devices o Wasting less energy

Energy Conservation Poster Create a poster that includes… an energy conservation method around the home a slogan to convey that message a picture that supports your message an explanation of why this method saves energy This will count as a formative grade

Cities and Towns ● Osage, IA o 3,600 people saved $1 million/year  Sealed doors and windows  New efficient furnaces  Insulated water heaters o Businesses moved to the area o Unemployment is down

Around the Home ● Spend $1,500/year on energy costs ● Much is wasted o Insulation o Efficient windows o Weather stripping o Wash clothes in cold water