Energy Efficiency and Renewable Energy. Chapter 16 G. Tyler Miller’s Living in the Environment 13th Edition. Key Concepts. Improving energy efficiency Solar energy Hydropower (flowing water) Wind Biomass Hydrogen fuel Geothermal Decentralized power systems. Doing more with less.
Energy Efficiency and Renewable Energy Chapter 16 G. Tyler Miller’s Living in the Environment 13th Edition
Key Concepts Improving energy efficiency Solar energy Hydropower (flowing water) Wind Biomass Hydrogen fuel Geothermal Decentralized power systems
Doing more with less Energy efficiency is the percentage of total energy input into an energy conversion device or system that does useful work and 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! Fig. 16-2 p. 381
The Importance of Improving Energy Efficiency Lower life cycle cost Initial cost plus lifetime operating cost Net energy efficiency Total amount of useful energy available minus the amount of energy used (First Law of Thermodynamics) automatically wasted (Second Law of Thermodynamics) unnecessarily wasted. Least Efficient Incandescent light bulb (5%) Internal combustion engine (10-15%) 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.
Uranium mining (95%) Uranium processing and transportation (57%) Power plant (31%) Transmission of electricity (85%) Resistance heating (100%) Uranium 100% 14% 14% 17% 95% 54% Waste heat Waste heat Waste heat Waste heat Electricity from Nuclear Power Plant Sunlight 100% 90% Waste heat Passive Solar Energy Efficiency
Could we save energy by recycling energy? No Second Law of Thermodynamics
Ways to Improve Energy Efficiency In Our Homes Insulation Eliminate air leaks Air-to-air heat exchangers Industry Cogeneration Two useful sources of energy are produced from the same fuel source Efficient electric motors High efficiency lighting 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 1975-2006. The governmentCorporate Average Fuel Economy (CAFE) has not increased after 1985. Figure 17-5
Increased Fuel Economy • Rechargeable battery systems • Hybrid electric-internal combustion engine • Fuel cells
Hybrid Car (Electric – Internal Combustion Engine) A C Electric motor Combustion engine D B Fuel tank Battery bank E Regulator F Transmission B A E F C D Fuel Electricity
Fuel cell stack Fuel tank A C D B Turbo compressor E Traction inverter Electric motor / transaxle B A E C D Fuel Cell Cars Fuel Electricity
1 2 3 4 H2 Cell splits H2 into protons and electrons. Protons flow across catalyst membrane. Hydrogen gas 3 1 O2 React with oxygen (O2). 2 Produce electrical energy (flow of electrons) to power car. 4 H2O Emits water (H2O) vapor.
The Solar-Hydrogen Revolution • Extracting hydrogen efficiently • Storing hydrogen • Fuel cells
Fuel Cells Advantages Energy efficiencies of 65-90% No moving parts Quiet Emit only water and heat More reliable Disadvantage Cost
Using Solar Energy to Provide Heat and Electricity • Active solar heating • Passive 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
Producing Electricity from Moving Water • Large-scale hydropower • Small-scale hydropower • Pumped-storage hydropower
Producing Electricity from Moving Water • 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. 16-28 p. 402 Fig. 16-29 p. 402
Producing Energy from Biomass • Biofuels • Biomass plantations • Crop residues • Animal manure • Biogas • Ethanol • Methanol
Geothermal Energy Fig. 16-36p. 409 • Geothermal reservoirs • Dry steam • Wet steam • Hot water • Molten rock • Hot dry-rock zones
Geothermal Reservoirs Fig. 16-37 p. 410
Entering the Age of Decentralized Micropower Fig. 16-40 p. 411 Fig. 16-39 p. 411 • Current Centralized power systems • Future Decentralized power systems • Micropower systems