Renewable Energy Chapters16 Living in the Environment, 11 th Edition, Miller Advanced Placement Environmental Science La Canada High School Dr. E

Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability

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 (%) ß ßDry-cell flashlight battery90 ß ßHome gas furnace85 ß ßStorage battery70 ß ßHome oil furnace65 ß ßSmall electric motor62 ß ßSteam power plant38 ß ßDiesel engine38 ß ßHigh-intensity lamp32 ß ßAutomobile engine 25 ß ßFluorescent lamp22 ß ßIncandescent lamp 4

Energy Efficiency percentage of energy input that does useful work in an energy conversion system

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

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

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.

Solar Energy Passive solar ßLarge south-facing windows, heavy drapes to trap heat at night, interior bricks to trap heat ßShade windows in summer ßEven 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 ßPhotovoltaic (PV) panels can be used to convert the energy from the sun into electricity. ßElectrons from the silicon in the PV panel are “pushed” through a wire by photons from the sun creating an electric current.

Solar Domestic Hot Water (SDHW) ßAn open circuit hot water system heats the domestic water directly on the roof of the building ßThe water flows from the heat collector into the hot water tank to be used in the house ßIntegration of solar energy conservation in homes can reduce energy consumption by 75-90%. ß SOLAR%20AMERICA%5B1%5D.ppt

Photovoltaic (Solar) Cells Provides electricity for buildings

A typical photovoltaic cell

Inside the PV cell ßPV cells are made from silicon alloys ßPV module ß1cm by 10cm cells ß36 cells connected SOLAR%20AMERICA%5B1%5D.ppt

Solar - Advantages ßNo greenhouse gas emissions ßUnlimited resource in certain areas ßLand disturbance is minimal (in passive solar heating) ßSolar cells are reliable and quiet with no moving parts

Solar - Disadvantages ßOnly reliable in certain areas ßExpensive to install (active solar power) ßSolar thermal plants require a lot of space (habitat destruction) ßManufacture of solar cells produces water pollution ßElectricity must be stored in batteries (expensive)

Solar Thermal Techniques Solar Two SOLAR%20AMERICA%5B1%5D.ppt

Heliostats ßHeliostats provide concentrated sunlight to the power tower ßThe reflecting mirrors follow the sun along its daily trajectory SOLAR%20AMERICA%5B1%5D.ppt

Power Tower ßSunlight from mirrors are reflected to fixed receiver in power tower ßFluid transfers the absorbed solar heat into the power block ßUsed to heat a steam generator Solar One SOLAR%20AMERICA%5B1%5D.ppt

Solar-Hydrogen Revolution  Splitting water can produce H 2 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

Energy Efficiency Solar EnergyHydropower Wind Power Biomass Geothermal Sustainability

History of Hydroelectric ßB.C. - Used by the Greeks to turn water wheels for grinding wheat into flour, more than 2,000 years ago ß U.S. Army Corps of Engineers founded, with establishment of Chief Engineer for the Continental Army ß 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. hydroelectric/hydro.ppt

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

hydroelectric/hydro.ppt

Turbine Technologies ßReaction ßfully immersed in fluid ßshape of blades produces rotation hydroelectric/hydro.ppt

Hydroelectric - Disadvantages ßDestroys habitats ßDecreases fish populations below the dam ßChanges wildlife populations above the dam ßDisplaces people (Three Gorges dam in China) ßCreates earthquakes ßMay cause flooding if the dam breaks ßInhibits fish migration (salmon)

Tidal Power Plant

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

Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability

Rotary Windmill

Vertical Blades

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

Wind is the fastest-growing energy sector ßWind farms: turbines erected in groups of up to hundreds of turbines ßCalifornia 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 ßNorth Dakota

Optimization ßLow Torque – Rapid Speed ßgood for electrical generation ßHigh Torque – Slow Speed ßgood for pumping water ßSmall generator ßlow wind speeds ßcaptures small amount of energy ßLarge generator ßhigh wind speeds ßmay not turn at low speeds

Source: American Wind Energy Association

Energy Efficiency Solar Energy Hydropower Wind PowerBiomass Geothermal Sustainability

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 ßUrban wastes can be burned in incinerators to produce electricity and heat

Types of Biomass Fuel

Conversion Processes Biomass Feedstock – – Trees – – Forest Residues – – Grasses – – Agricultural Crops – – Agricultural Residues – – Animal Wastes – – Municipal Solid Waste Fuels: Ethanol Renewable Diesel Methanol Hydrogen Electricity Heat Products – – Plastics – – Foams – – Solvents – – Coatings – – Chemical Intermediates – – Phenolics – – Adhesives – – Fatty acids – – Acetic Acid – – Carbon black – – Paints – – Dyes, Pigments, and Ink – – Detergents – – Etc. Biorefinery - - Acid Hydrolysis/Fermentation - - Enzymatic Fermentation - Gas/liquid Fermentation - Thermochemical Processes - Gasification/Pyrolysis - Combustion - Co-firing

Biomass - Advantages ßPotentially renewable if properly managed ßPlants can be converted to biofuels (gasohol, biodesiel) and burned in vehicle engines ßNo net increase in greenhouse gases as long as rate of removal of plants equals rate of burning ßModerate to high energy yield

Biomass - Disadvantages ßPresently most biomass sources are being used unsustainably ßWood smoke produces air pollution (particulates)

Energy Efficiency Solar Energy Hydropower Wind Power BiomassGeothermal Sustainability

Geothermal Energy  Geothermal energy can be used to heat buildings and to produce electricity  Geothermal reservoirs can be depleted if heat is removed faster than natural processes renew it, but the potential supply is vast

The origins of geothermal energy

Technology ßGeothermal Heat Pumps ßshallow ground energy ßDirect-Use ßhot water can be piped to facilities ßPower Plants ßsteam and hot water drive turbines ßdry steam plants ßflash steam plants ßbinary cycle plants geothermal/GeothermalEnergy.ppt

Dry Steam Power Plants ßHydrothermal fluids are primarily steam ßSteam goes directly to turbine ßNo fossil fuels geothermal/GeothermalEnergy.ppt

Flash Steam Power Plant ßFluids above 200 degrees Celsius ßFluid is sprayed into tank at lower pressure ßFluid rapidly vaporizes ßSteam drives turbine geothermal/GeothermalEnergy.ppt

Binary Cycle Power Plant ßCooler water (below 200 degrees Celsius) ßHot thermal fluid and a second fluid pass through heat exchanger geothermal/GeothermalEnergy.ppt

Geothermal - Advantages ßModerate energy yields ßReliable ßCompetitive Cost for producing electricity in certain areas close to geologic activity ßFewer greenhouse gases produced

Geothermal - Disadvantages ßHabitat/Ecosystem Destruction ßOdor and noise ßCost – not practical to transport it ßOnly available near areas of geologic activity

Benefits ßClean Energy ßone sixth of carbon dioxide vs. natural gas ßvery little if any nitrous oxide or sulfur compounds ßAvailability ß24 hours a day, 365 days a year ßHomegrown ßRenewable geothermal/GeothermalEnergy.ppt

Environmental Effects ßOnly emission is steam ßSalts and dissolved minerals reinjected ßSome sludge produced ßMineral extraction ßLittle Visual Impact ßSmall acreage, no fuel storage facilities geothermal/GeothermalEnergy.ppt

Location ßHot geothermal fluid ßLow mineral and gas content ßShallow aquifers ßProducing and reinjecting the fluid ßPrivate land ßSimplifies permit process ßProximity to transmission lines geothermal/GeothermalEnergy.ppt

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Future ßOnly tiny fraction is currently used ßDry hot rock heated by molten magma ßDrill into rock and circulate water geothermal/GeothermalEnergy.ppt

A typical hydrogen fuel cell

Energy Efficiency Solar Energy Hydropower Wind Power Biomass GeothermalSustainability

Suggestions to make the transition to a more sustainable energy future.