Renewable Energy Chapters16 Living in the Environment , 11 th Edition, Miller

Renewable EnergyChapters16Living in the Environment, 11th Edition, Miller Advanced Placement Environmental Science La Canada High School Dr. E

Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Energy Efficiency • Increasing energy efficiency of common devices has economic and environmental advantages • Reducing oil imports • Prolonging fossil fuel supplies • Reducing pollution and environmental degradation • Saving money • Buys time to develop new technology • Creating jobs

Efficiency of Some Common Devices Device Efficiency (%) • Dry-cell flashlight battery 90 • Home gas furnace 85 • Storage battery 70 • Home oil furnace 65 • Small electric motor 62 • Steam power plant 38 • Diesel engine 38 • High-intensity lamp 32 • Automobile engine 25 • Fluorescent lamp 22 • Incandescent lamp 4

Energy Efficiency percentage of energy input that does useful work in an energy conversion system www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Ways to Improve Energy Efficiency • Between 1985 and 2001, the average fuel efficiency for new motor vehicles sold in the United States leveled off or declined • Fuel-efficient models account for only a tiny fraction of car sales • Hybrid-electric cars are now available and sales are expected to increase • Fuel-cell cars that burn hydrogen fuel will be available within a few years • Electric scooters and electric bicycles are short-range transportation alternatives

Energy use of various types of transportation www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Ways to Improve Energy Efficiency • Superinsulated house is more expensive than a conventional house, but energy savings pay back the extra cost • Strawbale houses have the additional advantage of using an annually renewable agricultural residue, thus slowing deforestation

Ways to Improve Energy Efficiency • Existing homes can be made more energy efficient • adding insulation • plugging leaks • installing energy-saving windows • wrapping water heaters • installing tankless models • buying energy-efficient appliances and lights

Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability

Solar Energy • Buildings can be heated • passive solar heating system • active solar heating system • Solar thermal systems are new technologies that collect and transform solar energy into heat that can be used directly or converted to electricity • Photovoltaic cells convert solar energy directly into electricity

Suitability of Solar Usage best when more than 60% of daylight hours sunny www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Solar Heating Passive system: Absorbs & stores heat from the sun directly within a structure Active system: Collectors absorb solar energy, a pump supplies part of abuildings heating or water heating needs. www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Solar Energy Passive solar • Large south-facing windows, heavy drapes to trap heat at night, interior bricks to trap heat • Shade windows in summer • Even though back up systems are required, and solar heating may only lessen the need for heating oil a few %, it will help us adapt to diminishing oil supplies. Active solar • Photovoltaic (PV) panels can be used to convert the energy from the sun into electricity. • Electrons from the silicon in the PV panel are “pushed” through a wire by photons from the sun creating an electric current.

www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Solar Domestic Hot Water (SDHW) • An open circuit hot water system heats the domestic water directly on the roof of the building • The water flows from the heat collector into the hot water tank to be used in the house • Integration of solar energy conservation in homes can reduce energy consumption by 75-90%. • www.iea-shc.org www.earlham.edu/~parkero/Seminar/ SOLAR%20AMERICA%5B1%5D.ppt

Photovoltaic (Solar) Cells Provides electricity for buildings www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

A typical photovoltaic cell

Inside the PV cell • PV cells are made from silicon alloys • PV module • 1cm by 10cm cells • 36 cells connected www.earlham.edu/~parkero/Seminar/ SOLAR%20AMERICA%5B1%5D.ppt

Solar - Advantages • No greenhouse gas emissions • Unlimited resource in certain areas • Land disturbance is minimal (in passive solar heating) • Solar cells are reliable and quiet with no moving parts

Solar - Disadvantages • Only reliable in certain areas • Expensive to install (active solar power) • Solar thermal plants require a lot of space (habitat destruction) • Manufacture of solar cells produces water pollution • Electricity must be stored in batteries (expensive)

Solar Thermal Techniques SolarTwo www.earlham.edu/~parkero/Seminar/ SOLAR%20AMERICA%5B1%5D.ppt

Heliostats • Heliostats provide concentrated sunlight to the power tower • The reflecting mirrors follow the sun along its daily trajectory www.earlham.edu/~parkero/Seminar/ SOLAR%20AMERICA%5B1%5D.ppt

Power Tower • Sunlight from mirrors are reflected to fixed receiver in power tower • Fluid transfers the absorbed solar heat into the power block • Used to heat a steam generator Solar One www.earlham.edu/~parkero/Seminar/ SOLAR%20AMERICA%5B1%5D.ppt

Solar-Hydrogen Revolution • Splitting water can produce H2 gas • If scientists and engineers can learn how to use forms of solar energy to decompose water cheaply, they will set in motion a solar-hydrogen revolution • Hydrogen-powered fuel cells could power vehicles and appliances

History of Hydroelectric • B.C. - Used by the Greeks to turn water wheels for grinding wheat into flour, more than 2,000 years ago • 1775 - U.S. Army Corps of Engineers founded, with establishment of Chief Engineer for the Continental Army • 1880 - Michigan's Grand Rapids Electric Light and Power Company, generating electricity by dynamo, belted to a water turbine at the Wolverine Chair Factory, lit up 16 brush-arc lamps. www.usd.edu/phys/courses/scst601/ hydroelectric/hydro.ppt

History of Hydroelectric • By 1940 - 40% of electrical generation was hydropower • Between 1921 and 1940 - conventional capacity in the U.S. tripled; almost tripled again between 1940 and 1980 • Currently - about 10% of U.S. electricity comes from hydropower. www.usd.edu/phys/courses/scst601/ hydroelectric/hydro.ppt

www.usd.edu/phys/courses/scst601/ hydroelectric/hydro.ppt

Turbine Technologies • Reaction • fully immersed in fluid • shape of blades produces rotation www.usd.edu/phys/courses/scst601/ hydroelectric/hydro.ppt

Hydroelectric - Disadvantages • Destroys habitats • Decreases fish populations below the dam • Changes wildlife populations above the dam • Displaces people (Three Gorges dam in China) • Creates earthquakes • May cause flooding if the dam breaks • Inhibits fish migration (salmon)

Tidal Power Plant www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Wave energy • The motion of wind-driven waves at the ocean’s surface is converted into electricity.

Rotary Windmill www.usd.edu/phys/courses/scst601/wind_energy.ppt

Vertical Blades www.usd.edu/phys/courses/scst601/wind_energy.ppt

Modern wind turbines convert kinetic energy • Wind turbines: devices that turn wind energy into electricity • Towers are 40–100 m (131–328 ft) tall. • Wind Energy

Wind is the fastest-growing energy sector • Wind farms: turbines erected in groups of up to hundreds of turbines • California and Texas produce the most wind power in the U.S.

Energy from Wind • Production of electricity and hydrogen gas by wind farms is expected to increase • Western Europe currently leads in the development of wind power • Land used for wind farms also can be used for ranching or crops and most profits stay in local communities • North Dakota

Optimization • Low Torque – Rapid Speed • good for electrical generation • High Torque – Slow Speed • good for pumping water • Small generator • low wind speeds • captures small amount of energy • Large generator • high wind speeds • may not turn at low speeds www.usd.edu/phys/courses/scst601/wind_energy.ppt

Source: American Wind Energy Association www.usd.edu/phys/courses/scst601/wind_energy.ppt

Energy from Biomass • In the developing world, most people heat homes and cook by burning wood or charcoal • Plant materials and animal wastes also can be converted into biofuels, • Biogas • Liquid ethanol • Liquid methanol • Urban wastes can be burned in incinerators to produce electricity and heat www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Renewable Energy Chapters16 Living in the Environment , 11 th Edition, Miller