Energy Efficiency and Renewable Energy Chapter 16 G. Tyler Miller’s Living in the Environment 13th Edition Chapter 16 G. Tyler Miller’s Living in the Environment 13th Edition

Key Concepts Improving energy efficiencyImproving energy efficiency Solar energySolar energy Hydropower (flowing water)Hydropower (flowing water) WindWind BiomassBiomass Hydrogen fuelHydrogen fuel GeothermalGeothermal Decentralized power systemsDecentralized power systems

Doing more with less Energy efficiencyEnergy efficiency –is the percentage of total energy input into an energy conversion device or system that 1)does useful work and 2)is not converted to low-quality heat.

The Importance of Improving Energy Efficiency 84% of all commercial energy produced in the U.S. is wasted!84% of all commercial energy produced in the U.S. is wasted! Fig p. 381

The Importance of Improving Energy Efficiency Lower life cycle costLower life cycle cost –Initial cost plus lifetime operating cost Net energy efficiencyNet energy efficiency –Total amount of useful energy available minus the amount of energy used (First Law of Thermodynamics)used (First Law of Thermodynamics) automatically wasted (Second Law of Thermodynamics)automatically wasted (Second Law of Thermodynamics) unnecessarily wasted.unnecessarily wasted. Least Efficient Incandescent light bulb (5%)Incandescent light bulb (5%) Internal combustion engine (10-15%)Internal combustion engine (10-15%) Nuclear power plants (8-14%)Nuclear power plants (8-14%) Least Efficient Incandescent light bulb (5%)Incandescent light bulb (5%) Internal combustion engine (10-15%)Internal combustion engine (10-15%) Nuclear power plants (8-14%)Nuclear power plants (8-14%)

REDUCING ENERGY WASTE AND IMPROVING ENERGY EFFICIENCY Four widely used devices waste large amounts of energy: –Incandescent light bulb: 95% is lost as heat. –Internal combustion engine: 94% of the energy in its fuel is wasted. –Nuclear power plant: 92% of energy is wasted through nuclear fuel and energy needed for waste management. –Coal-burning power plant: 66% of the energy released by burning coal is lost.

Efficiencies (fig p. 382)

Uranium 100% Electricity from Nuclear Power Plant 14% Resistance heating (100%) 90% Waste heat Passive Solar Sunlight 100% Waste heat 14% Transmission of electricity (85%) 17% Waste heat Power plant (31%) 54% Waste heat Uranium processing and transportation (57%) 95% Waste heat Uranium mining (95%) Energy Efficiency

Could we save energy by recycling energy? NoNo Second Law of ThermodynamicsSecond Law of Thermodynamics

Ways to Improve Energy Efficiency In Our Homes Insulation Insulation Eliminate air leaks Eliminate air leaks Air-to-air heat exchangers Air-to-air heat exchangers Industry Cogeneration Cogeneration –Two useful sources of energy are produced from the same fuel source Efficient electric motors Efficient electric motors High efficiency lighting High efficiency lighting Increased fuel economy Increased fuel economyIndustry Cogeneration Cogeneration –Two useful sources of energy are produced from the same fuel source Efficient electric motors Efficient electric motors High efficiency lighting High efficiency lighting Increased fuel economy Increased fuel economy

Saving Energy in Existing Buildings About one-third of the heated air in typical U.S. homes and buildings escapes through closed windows and holes and cracks. Figure 17-11

WAYS TO IMPROVE ENERGY EFFICIENCY Average fuel economy of new vehicles sold in the U.S. between The government Corporate Average Fuel Economy (CAFE) has not increased after Figure 17-5

Increased Fuel Economy  Rechargeable battery systems  Hybrid electric-internal combustion engine  Fuel cells

Electricity Fuel Combustion engine A Fuel tank B Electric motor C Battery bank D RegulatorE TransmissionF A B C D E F Hybrid Car (Electric – Internal Combustion Engine)

A C E D B Electricity FuelA Fuel cell stack B Fuel tank C Turbo compressor D Traction inverter E Electric motor / transaxle Fuel Cell Cars

H2H2 O2O2 H2OH2O Hydrogen gas Emits water (H 2 O) vapor. Produce electrical energy (flow of electrons) to power car. React with oxygen (O 2 ). Cell splits H 2 into protons and electrons. Protons flow across catalyst membrane.

The Solar-Hydrogen Revolution  Extracting hydrogen efficiently  Storing hydrogen  Fuel cells

Fuel Cells Advantages Energy efficiencies of 65-90%Energy efficiencies of 65-90% No moving partsNo moving parts QuietQuiet Emit only water and heatEmit only water and heat More reliableMore reliableDisadvantage CostCost

Using Solar Energy to Provide Heat and Electricity  Passive solar heating  Active solar heating

Using Solar Energy to Provide High- Temperature Heat and Electricity  Solar thermal systems

Using Solar Energy to Provide High- Temperature Heat and Electricity  Photovoltaic (PV) cells

Using Solar Energy to Provide High- Temperature Heat and Electricity

Producing Electricity from Moving Water  Large-scale hydropower  Small-scale hydropower  Pumped-storage hydropower  Large-scale hydropower  Small-scale hydropower  Pumped-storage hydropower

Producing Electricity from Moving Water  Tidal power plant  Wave power  Tidal power plant  Wave power

Producing Electricity from Heat Stored in Water  Ocean thermal energy conversion (OTEC)  Saline solar ponds  Freshwater solar ponds

Producing Electricity from Wind Fig p. 402 Fig p. 402

Producing Energy from Biomass Biofuels Biomass plantations Crop residues Animal manure Biogas Ethanol Methanol Biofuels Biomass plantations Crop residues Animal manure Biogas Ethanol Methanol

Geothermal Energy  Geothermal reservoirs  Dry steam  Wet steam  Hot water  Molten rock  Hot dry-rock zones Fig p. 409

Geothermal Reservoirs Fig p. 410

Entering the Age of Decentralized Micropower  Current Centralized power systems  Future Decentralized power systems  Micropower systems Fig p. 411 Fig p. 411

Solutions: A Sustainable Energy Strategy