Environmental Science 101 Energy 1 Web-Based Course Lecture Outline: 5. RENEWABLE ENERGY RESOURCES MODULE 5.1 Improving Energy Efficiency A. Improving Energy Efficiency MODULE 5.2 Geothermal, Hydro and Solar Energy B. Geothermal Energy C. Hydroelectric Energy D. Solar Energy MODULE 5.3 Wind, Tidal and Biomass Energy E. Wind Energy F. Tidal Energy G. Bioconversion Energy Terms You Should Know: Hydroelectric energy Wind energy Tidal energy Solar energy Biomass energy Conservation Geothermal energy Cogeneration Gasohol Photovoltaic cell Passive solar system Energy efficiency Active solar system Wind farms Turbines Penstocks Solar cooker Parabolic mirror Biofuel Learning Objectives: When you are finished with this section you should be able to: 1. Describe what can be done to improve energy efficiency in the USA. 2. List ways that you as an individual can save energy. 3. Describe the pros and cons of hydroelectric energy production. 4. List the pros and cons of solar, wind, tidal, geothermal and biomass energy. 5. Rank renewable energy sources from greatest to least potential looking 50 years into the future. Justify your ranking. Reading Assignment: Brennan and Withgott: Chapter 20; pages 588601. Chapter 21; pages 602628.
UNIT 5: ENERGY 2 5. RENEWABLE ENERGY RESOURCES MODULE 5.1 Improving Energy Efficiency A. IMPROVING ENERGY EFFICIENCY 1. Doing More with Less 84% of all commercial energy used in the USA is wasted Energy efficiency ENERGY EFFICIENCY the percentage of total energy input that does useful work Increasing energy efficiency cars cars MPG 1975 1988 1992 1994 1997 2001 1 mpg on US cars =
3 2. CASE STUDY 1 Compact fluorescents (CFLs) vs Incandescent Light Bulbs Efficiency: incandescent lighting fluorescent lighting CFL Sales: 1988 1992 1996 2000 (est) CFLs last 10X as long as incandescents In 1999 incandescents out sold CFLs by 25:1 CFL technology continues to improve
4 3. CASE STUDY 2 THE CAR OPTIONS: Internal Combustion Engine 10% Efficiency OPTION A: Internal Combustion Engine DO NOTHING! keep internal combustion engine fading oil reserves OPTION B: Hybrid Car Consists of: small battery to provide energy for acceleration and hill climbing Hybrid Cars Toyota and Honda sell hybrids
5 OPTION C: Hydrogen Fuel Cells lower CO 2 emissions 4. Benefits of reducing energy waste: Making non-renewable fuels last longer Decreasing dependence on oil imports Lessening need for military intervention in the Middle East (oil interests) USA Japan 5. Saving Energy CONSERVATION (1) using only what we need, and (2) using it efficiently Roadblocks to energy conservation:
6 federal programs subsidize fossil fuels oil cost = $36 per barrel real oil cost = a. Using Waste Heat insulates house, eliminates air leaks store heat in summer months à b. Transportation consumes 63% of oil used in USA (up from 50% in 1973) improve fuel efficiency of planes and ships
7 6.a A Look at USA in 2003 Use of renewable energy in the USA today (2003): % of our energy needs; split as follows: % Hydropower % Biomass energy % Geothermal % Solar % Wind 6.b A Look at USA in 2050
MODULE 5.2 Geothermal, Hydro and Solar Energy 8 B. GEOTHERMAL ENERGY GEOTHERMAL ENERGY heat from the Earth s mantle transferred to underground concentrations of dry steam, wet steam or hot water 20 countries now use some geothermal energy USA produces 44% of the world s geothermal power Iceland heats capital city PROS: can be used to turn turbines use all the time CONS: can degrade local environment: minerals, salts, toxic metals, hydrogen sulfide gas
9 C. HYDROELECTRIC ENERGY Rely on dams; environmental costs Stored reservoir water flows through Penstocks (pipes) at controlled rates and turn turbines to produce electricity In 1925 hydropower generated 40% of the world s electricity Today World Today USA In USA most of potential hydroelectric energy is already developed few new large dams will be built Hydropower is renewable, but adversely impacts:
10 PROS: takes fertile land out of production well developed technology CONS: environmental impacts D. SOLAR ENERGY Vast potential as a renewable and sustainable energy source Current power costs: solar 12 per kw hydropower coal utility nuclear utility Types of systems: PASSIVE SOLAR SYSTEM captures sunlight directly within a structure and converts into low temperature heat for space heating ACTIVE SOLAR SYSTEM specially designed collectors absorb solar energy and a fan or a pump is used to supply part of building s space heating or water heating needs
11 PHOTOVOLTAIC CELLS (SOLAR CELLS) solar energy is directly converted into electrical energy Parabolic mirrors are mirrors that focus light from a large area onto a simple, central point focus intense heat on central tube; Solar cookers Solar box cooker smaller, insulated box; cooks at 120 C POTENTIAL: with an aggressive effort starting now solar could provide: 2010 2050 PROS: fuel is free only costs are for devices to capture and store energy
12 CONS: source is intermittent nights and cloudy days unsightliness on houses MODULE 5.3 Wind, Tidal and Biomass Energy E. WIND ENERGY 2% of sun s energy striking the Earth is converted into wind Use wind turbines Wind power is the world's fastest growing energy source Germany is the world leader, followed by Denmark In the USA most wind turbines are in California; however, many have been installed on the Great Plains in the past 3 years
13 Unlimited resource of energy on favorable sites Economical only in areas with steady winds With massive adaptation, wind power could provide: R&D: PROS: only cost is for devices to capture and store it clean, renewable, small land requirement technology is well developed CONS: wind does not blow all the time storage of energy is a weakness
14 F. TIDAL ENERGY taking advantage of tides ocean water flows in and out of coastal bays and estuaries twice a day water flow could be used to spin turbines pilot plants in Canada and France G. BIOCONVERSION ENERGY (Burning) burning organic materials Types of bioenergy: burning wood
15 burning trash methane production alcohol production oil seed crops burning animal and crop residues
16 all bioenergy sources have environmental costs: currently supplies 50% of energy used in LDC s PROS: CONS: burning wastes gets rid of problem, generates power high net energy efficiency