Energy Chapter 13 Sections 5-8

Question of the Day Name three of the six types of Renewable Energy. Name three of the six types of Renewable Energy. Or all six for two monkey faces. Or all six for two monkey faces.

Answer of the Day The six types of Renewable Energy are. Solar Flowing water WindBiomassHydrogenGeothermal

Renewable Energy Sustainability (Fig. 6-18, p. 126) mostly depends on solar energy Sustainability (Fig. 6-18, p. 126) mostly depends on solar energy Why renewable energy is not more widely used Why renewable energy is not more widely used Passive and active solar heating Passive and active solar heating Cooling homes with less energy Cooling homes with less energy

PASSIVE Stone floor and wall for heat storage Superwindow Winter sun Summer sun Superwindow Heavy insulation Passive and Active Solar Heating Fig a, p. 313

Fig b, p. 313 Hot water tank Pump Heat exchanger Superwindow Heat to house (radiators or forced air duct) ACTIVE Heavy insulation Passive and Active Solar Heating

Fig a, p. 314 Direct Gain Ceiling and north wall heavily insulated Hot air Super insulated windows Cool air Warm air Summer sun Winter sun Earth tubes Passive Solar Designs

Fig b, p. 314 Greenhouse, Sunspace, or Attached Solarium Insulated windows Cool air Warm air Passive Solar Designs Summer cooling vent

Fig c, p. 314 Earth Sheltered Earth Triple-paned or superwindows Flagstone floor for heat storage Reinforced concrete, carefully waterproofed walls and roof Passive Solar Designs

Energy is free Net energy is moderate (active) to high (passive) Quick installation No CO 2 emissions Very low air and water pollution Very low land disturbance (built into roof or window) Moderate cost (passive) Need access to sun 60% of time Blockage of sun access by other structures Need heat storage system High cost (active) Active system needs maintenance and repair Active collectors unattractive AdvantagesDisadvantages Trade-offs Passive or Active Solar Heating Fig , p. 314 Tradeoffs of Passive and Active Solar Heating

Solar Energy for High- Temperature Heat and Electricity Solar thermal systems Solar thermal systems Central receiver system (power tower) Central receiver system (power tower) Heliostats Heliostats Solar thermal plant Solar thermal plant Solar cookers Solar cookers Photovoltaic (solar) cells Photovoltaic (solar) cells

Moderate net energy Moderate environmental Impact No CO 2 emissions Fast construction (1-2 years) Costs reduced with natural gas turbine backup Low efficiency High costs Needs backup or storage system Need access to sun most of the time High land use May disturb desert areas Advantages Disadvantages Trade-Offs Solar Energy for High-Temperature Heat and Electricity Fig , p. 315 Tradeoffs of Solar Energy for High- Temperature Heat and Electric

Fig , p. 315 Tradeoffs of Solar Energy for High- Temperature Heat and Electric

Fig a, p. 315 Single Solar Cell Boron- enriched silicon Junction Phosphorus- enriched silicon Tradeoffs of Solar Energy for High- Temperature Heat and Electric

Solar Cells Provide Electricity for a Village Fig , p. 316

Fairly high net energy Work on cloudy days Quick installation Easily expanded or moved No CO 2 emissions Low environmental impact Last years Low land use (if on roof or built into walls or windows) Reduce dependence on fossil fuels Need access to sun Low efficiency Need electricity storage system or backup High land use (solar cell power plants) could disrupt desert areas High costs (but should be competitive in 5-15 years) DC current must be converted to AC AdvantagesDisadvantages Trade-Offs Solar Cells Fig , p. 316 Tradeoffs of Solar Cells

Producing Electricity from Flowing Water Dams and reservoirs Dams and reservoirs Greenhouse emissions Greenhouse emissions Large- and small-scale hydropower Large- and small-scale hydropower Tidal and wave energy Tidal and wave energy

Moderate to high net energy High efficiency (80%) Large untapped potential Low-cost electricity Long life span No CO 2 emissions during operation May provide flood control below dam Provides water for year- round irrigation of crop land Reservoir is useful for fishing and recreation High construction costs High environmental impact from flooding land to form a reservoir High CO 2 emissions from biomass decay in shallow tropical reservoirs Floods natural areas behind dam Converts land habitat to lake habitat Danger of collapse Uproots people Decreases fish harvest below dam Decreases flow of natural fertilizer (silt) to land below dam AdvantagesDisadvantages Trade-Offs Large-Scale Hydropower Fig , p. 317 Tradeoffs of Large-Scale Hydropower

Question of the Day What is the difference between primary and secondary/tertiary oil recovery? What is the difference between primary and secondary/tertiary oil recovery?

Answer of the Day Primary recovery - natural pressure of the reservoir, combined with pumping equipment, brings oil to the surface. (10% of oil recovered) Primary recovery - natural pressure of the reservoir, combined with pumping equipment, brings oil to the surface. (10% of oil recovered) Secondary - water or gas is injected to displace oil. (20-40% of original oil) Secondary - water or gas is injected to displace oil. (20-40% of original oil) Tertiary - other gases, CO2, and chemicals, along with heat. Tertiary - other gases, CO2, and chemicals, along with heat.

Producing Electricity from Wind Becoming more popular, especially in Europe Becoming more popular, especially in Europe Indirect form of solar energy Indirect form of solar energy Great potential in the Great Plains states Great potential in the Great Plains states

Fig , p. 318 Wind Turbines

Fig a, p. 318 Wind Turbine Power cable Electrical generator Gearbox Wind Turbines

Fig b, p. 318 Wind Turbines Wind Farm

Moderate to high net energy High efficiency Moderate capital cost Low electricity cost (and falling) Very low environmental impact No CO 2 emissions Quick construction Easily expanded Land below turbines can be used to grow crops or graze livestock Steady winds needed Backup systems when needed winds are low High land use for wind farm Visual pollution Noise when located near populated areas May interfere in flights of migratory birds and kill birds of prey AdvantagesDisadvantages Trade-Offs Wind Power Fig , p. 318 Tradeoffs of Wind Power

Fig , p. 318 Biomass Fuel Stepped Art Solid Biomass Fuels Wood logs and pellets Charcoal Agricultural waste (stalks and other plant debris) Timbering wastes (branches, treetops, and wood chips) Animal wastes (dung) Aquatic plants (kelp and water hyacinths) Urban wastes (paper, cardboard), And other combustible materials Direct burning Conversion to gaseous and liquid biofuels Gaseous Biofuels Synthetic natural gas (biogas) Wood gas Liquid Biofuels Ethanol Methanol Gasonol

Producing Electricity from Biomass Wood, crop residues, and animal wastes Wood, crop residues, and animal wastes Liquid and gas biofuels Liquid and gas biofuels Biomass plantations Biomass plantations No net carbon dioxide emissions No net carbon dioxide emissions Biogas Biogas Ethanol, gasohol, and methanol fuels Ethanol, gasohol, and methanol fuels Methanol economy? Methanol economy?

Fuel from Animal Manure Fig , p. 319

Large potential supply in some areas Moderate costs No net CO 2 increase if harvested and burned sustainably Plantation can be located on semiarid land not needed for crops Plantation can help restore degraded lands Can make use of agricultural, timber, and urban wastes Nonrenewable if harvested unsustainably Moderate to high environmental impact CO 2 emissions if harvested and burned unsustainably Low photosynthetic efficiency Soil erosion, water pollution, and loss of wildlife habitat Plantations could compete with cropland Often burned in inefficient and polluting open fires and stoves AdvantagesDisadvantages Trade-Offs Solid Biomass Fig , p. 320 Tradeoffs of Solid Biomass Fuels

High octane Some reduction in CO 2 emission Reduced CO emissions Can be sold as gasohol Potentially renewable Large fuel tank needed Lower driving range Net energy loss Much higher cost Corn supply limited May compete with growing food on cropland Higher NO emission Corrosive Hard to start in colder weather AdvantagesDisadvantages Trade-Offs Ethanol Fuel Fig , p. 320 Tradeoffs of Ethanol Fuel

High octane Some reduction in CO 2 emissions Lower total air Pollution (30-40%) Can be made from natural gas, agricultural wastes, sewage sludge, and garbage Can be used to produce H 2 for fuel cells Large fuel tank needed Half the driving range Corrodes metal, rubber, plastic High CO 2 emissions if made from coal Expensive to produce Hard to start in cold weather AdvantagesDisadvantages Trade-Offs Methanol Fuel Fig , p. 321 Tradeoffs of Methanol Fuel

Geothermal Energy Earth’s internal heat Earth’s internal heat Geothermal heat pumps Geothermal heat pumps Geothermal exchange (geoexchange) Geothermal exchange (geoexchange) Dry and wet steam Dry and wet steam Hot water Hot water Molten rock (magma) Molten rock (magma) Hot dry-rock zones Hot dry-rock zones Warm-rock reservoir deposits Warm-rock reservoir deposits “The Geysers” “The Geysers”

Very high efficiency Moderate net energy at accessible sites Lower CO 2 emissions than fossil fuels Low cost at favorable sites Low land use Low land disturbance Moderate environmental impact Scarcity of suitable sites Depleted if used too rapidly CO 2 emissions Moderate to high local air pollution Noise and odor (H 2 S) Cost too high except at the most concentrated and accessible source AdvantagesDisadvantages Trade-Offs Geothermal Fuel Fig , p. 322 Tradeoffs of Geothermal Power

Hydrogen Power Realistic alternative to petroleum? Realistic alternative to petroleum? Hydrogen is environmentally friendly Hydrogen is environmentally friendly Hydrogen takes energy to produce Hydrogen takes energy to produce Fuel cells are expensive Fuel cells are expensive Science Spotlight, p. 323: Producing Hydrogen from Green Algae Found in Pond Scum Science Spotlight, p. 323: Producing Hydrogen from Green Algae Found in Pond Scum Iceland Iceland Storing hydrogen Storing hydrogen

Can be produced from plentiful water Low environmental impact Renewable if produced From renewable energy resources No CO 2 emissions if produced from water Good substitute for oil Competitive price if environmental and social costs are included in cost comparisons Easier to store than electricity Safer than gasoline and natural gas Nontoxic High efficiency (65-95%) in fuel cells Not found in nature Energy is needed to produce fuel Negative net energy CO 2 emissions if produced from carbon-containing compounds Nonrenewable if generated by fossil fuels or nuclear power High costs (but expected to come down) Will take 25 to 50 years to phase in Short driving range for current fuel cell cars No distribution system in place Excessive H 2 leaks may deplete ozone AdvantagesDisadvantages Trade-Offs Hydrogen Fig , p. 322 Tradeoffs of Hydrogen Power

A Sustainable Energy Strategy Improve energy efficiency Improve energy efficiency Rely more on renewable sources Rely more on renewable sources Shift to decentralized micropower systems Shift to decentralized micropower systems Natural gas and possibly nuclear fusion Natural gas and possibly nuclear fusion Reduce harmful environmental effects of fossil fuel use Reduce harmful environmental effects of fossil fuel use Role of government in developing sustainable energy Role of government in developing sustainable energy Political and economic issues Political and economic issues

© 2006 Brooks/Cole - Thomson Fig , p. 324 Bioenergy Power plants Wind farm Small solar cell power plants Fuel cells Solar cell rooftop systems Commercial Microturbines Industrial Transmission and distribution system Residential Small wind turbine Rooftop solar cell arrays Decentralized Power System

More Sustainable Energy Future More Renewable Energy Increase renewable energy to 20% by 2020 and 50% by 2050 Provide large subsidies and tax credits for renewable energy Use full-cost accounting and life cycle cost for comparing all energy alternatives Encourage government purchase of renewable energy devices Greatly increase renewable energy research and development Reduce Pollution and Health Risk Cut coal use 50% by 2020 Phase out coal subsidies Levy taxes on coal and oil use Phase out nuclear power or put it on hold until 2020 Phase out nuclear power subsidies Fig , p. 325 Improve Energy Efficiency Increase fuel-efficiency standards for vehicles, buildings, and appliances Mandate government purchases of efficient vehicles and other devices Provide large tax credits for buying efficient cars, houses, and appliances Offer large tax credits for investments in efficiency Reward utilities for reducing demand Encourage independent power producers Greatly increase efficiency research and development

What Can We Do? Drive a car that gets at least 15 kilometers per liter (35 miles per gallon) and join a carpool. Use mass transit, walking, and bicycling. Superinsulate your house and plug all air leaks. Turn off lights, TV sets, computers, and other electronic equipment when they are not in use. Wash laundry in warm or cold water. Use passive solar heating. For cooling, open windows and use ceiling fans or whole-house attic or window fans. Turn thermostats down in winter and up in summer. Buy the most energy-efficient homes, lights, cars, and appliances available. Turn down the thermostat on water heaters to 43-49ºC ( ºF) and insulate hot water heaters and pipes. What Can You Do? Energy Use ad Waste Fig , p. 326 © 2006 Brooks/Cole - Thomson