Chapter 17: Energy Efficiency
BIOMASS SOURCES AND TRADEOFFS
- wood -plant and animal waste -ethanol from plant material -ethanol from algae -biodiesel from plant material -biodiesel from waste oil -methane from animal waste TRADEOFFS •Rapid expansion of biofuels may (or may already) reduce the food available for consumption resulting in higher prices. •Extensive use of biofuels could have dramatic impacts on the use of agricultural land
What are some easy, cheap ways to conserve energy for the average homeowner
-Drive less, walk and bike more -Buy a hybrid car. -Use mass transit -Super insulate your home -Turn of lights, TV sets, computers, and other electronics when not in use -Wash laundry in warm or cold water -Use passive solar heating -To cool, open windows and use ceiling fans -Turn thermostats down in winter and up in summer -Buy energy efficient home lights, cars and appliances available -Turn down thermostat on water heater and insulate hot water heaters and pipes.
What effects does high energy use have on the environment?
-air pollution -water pollution -greenhouse gas emissions -deforestation -waste generation -species extinction -soil degradation -human health and safety hazards -unsustainable resource use
As a society, how did we become so reliant on nonrenewable fossil fuels?
-industrial revolution created need for cheap, efficient and plentiful fuels -led to the development of coal, oil, and natural gas as fuel sources from 1800s into 1900s -today more than 80% of our energy needs come from fossil fuels
What percent of the energy bill for an American home goes for heating water?
18%
What percentage of US oil consumption is directly related to transportaion
60%
Advantages and Disadvantages of Photovoltaic cells
ADVANTAGES fairly high net energy yield work on cloudy days quick installation easily expanded or moved no CO2 emissions low environmental impact last 20-40 years low land use (if on roof or built into walls or windows) reduces dependence on fossil fuels. DISADVANTAGES Need access to sun Low efficiency Need electricity storage system or backup Environmental costs not included in market price, High costs (but should be competitive in 5-15 years) High land use (solar-cell power plants) could disrupt desert areas DC current must be converted to AC
METHANOL
ADVANTAGES *High Octane *Some reduction in CO2 emissions *Lower total air pollution (30-40%) *Can be made from natural gas, agricultural waste, sewage, sludge, garbage, and CO2 *Can be used to produce H2 for fuel cells DISADVANTAGES *Large fuel tank needed *Half the driving range *Corrodes metal, rubber, plastic *Higher CO2 emissions if made from coal *Expensive to produce *Hard to start cars in cold weather
HYDROGEN
ADVANTAGES Can be produced from plentiful water Low environmental impact Renewable if produced from renewable energy resources. No CO2 emissions 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 (45-65%) in fuel cells. DISADVANTAGES Requires a large amount of energy to produce Not found as H2 in nature Negative net energy. Excessive H2 leaks may deplete ozone in the atmosphere. CO2 emissions if produced from carbon-containing compounds. Environmental costs not included in market price Nonrenewable if generated by fossil fuels or nuclear power. High costs (that may eventually come down). Will take 25 to 50 years to phase in. Short driving range for current fuel-cell cars. No fuel distribution system in place.
ETHANOL
ADVANTAGES OF ETHANOL *High Octane *Some reduction in CO2 emissions *High net energy (bagasse and switchgrass) *Reduced CO emissions *Can be sold as gaschol *Potentially renewable DISADVANTAGES OF ETHONAL *Large fuel tank needed *Low driving range *Much higher cost *Corn supply limited *May compete with growing food on cropland *Higher NO emissions *Corrosive *Hard to start in cold weather.
4. ______ ______ is the name for a system that produces two useful forms of energy from one fuel source. a. Regeneration b. Cogeneration c. Degeneration d. Post-generation
Cogeneration
DOWNSIDE OF GEOTHERMAL POWER AND WHAT SCOTLAND IS DOING
Downside Digging into the earth's crust is costly, and may trigger small earthquakes. Iceland and Geothermal power: 25% of electricity and 90% of hot water produced in Iceland is from geothermal power. Geothermal power is used in Iceland to heat pools, heat greenhouses, support fish farming, heating homes, used to keep pavements snow free, create electricity, and produce aluminum.
What is the first law of thermodynamics
Energy is conserved during any transfer process
13. ______ ______ is the most energy-efficient, cost-effective, and environmentally clean way to heat or cool a building. a. Passive solar b. Geothermal exchange c. Photovoltaic power d. Hydrogen power
Hydrogen fuel cell power
9. ______ What form of energy has high cost of construction, high environmental impact, and the potential to force the displacement of people and wildlife? a. nuclear power b. wind power c. solar power d. hydropower
Hydropower
benefits of CFL and LED lights
LED's use about one-seventh of the electricity required by an incandescent light bulb, and the total amount of mercury in all of the country's CFL's is a tiny fraction of the amount of mercury released every year by coal-fired power plants that produce the electricity that lights many energy-wasting incandescent bulbs.
5. ______ Which of the following is not a method for saving significant amounts of energy? a. Use cogeneration b. Replace electric motors with adjustable-speed drive motors c. Lower CAFE standards d. Replace incandescent bulbs with fluorescent bulbs
Lower CAFE standards
PROS AND CONS OF TIDAL POWER
PROS Renewable Non-polluting Reliable Predictable CONS High Cost Few suitable locations Possible negative effect on plants and animals in estuaries of the tidal basin
PROS AND CONS OF WIND POWER
PROS - moderate to high net energy yield, - high efficiency, - moderate capital cost, - low electricity cost, - very low environmental impact, - no CO2 emissions - quick construction, - easily expanded, - can be located at sea, and - land below turbines can be used to grow crops or graze livestock. CONS - steady winds needed, - backup systems needed when winds are low, - plastic components produced from oil, - environmental costs not included in market price, - high land use for wind farm, - visual pollution, noise when located near populated areas, - can kill birds and interfere with flights of migratory birds if not sited properly.
2. ______ Which of the following would not be a result of reducing energy waste? a. Prolonging fossil fuel supplies b. Keeping more money in local economies c. Higher net energy d. Prolonging development of technological advancements in renewable energy
Prolonging development of technological advancements in renewable energy
NET ZERO HOME
Reduce energy loads 2. Optimize design for passive strategies 3. Optimize design of active systems 4. Recover energy 5. Generate energy on-site 6. Buy energy/carbon offsets
What is Scotland doing
Scotland, a nation of 5.3 million could eliminate fossil fuels and nuclear energy in just 15 years. How? By combining annual reductions in energy use by 1 percent a year while adding more wind and hydropower and improving the efficiency of the electrical grid.
Can the United States use more Wind Power
The United States has some of the best wind resources in the world, with enough potential energy to produce nearly 10 times the country's existing power needs. Wind energy is now one of the most cost-effective sources of new generation, competing with new installations of coal, gas and nuclear power. Its cost has dropped steadily over the past few years, as wind turbine technology has improved. Wind farms in the Great Plains states have the potential to generate more than enough power for the lower 48 states, and have been dubbed the Saudi Arabia of wind energy
With moderate winds, a modern large wind turbine can generate about 250 kW of electricity, whereas a large nuclear power plant can generate 1,000 MW. a. How many wind turbines would be required to give the same output as one nuclear power plant?
Wind: 250kW = 0.250MW Nuclear: 1000MW 1000/0.250 = 4,000 wind turbines would be required to equal output of one nuclear power pant.
3. ______ Which of the following space heating energy systems has the highest net energy ratio over its estimated lifetime? a. a passive solar system b. an oil system c. a natural gas system d. electric resistance heating
a passive solar system
Is there simply a way to conserve more energy and increase the efficiency of the products and processes we use?
conserving and increasing energy efficiency
What is energy efficiency
how much usable energy remains after an energy transfer process is complete
6. ______ A fuel cell combines ______ and ______ to produce electricity. a. carbon dioxide, hydrogen b. a battery, gasoline c. water, ethanol d. hydrogen, oxygen
hydrogen and oxygen
8. ______ Which of the following is a disadvantage of using solar energy to generate high-temperature heat and electricity? a. may disturb desert areas b. high carbon dioxide emissions c. low net energy d. takes 10-20 years to construct
may disturb desert areas low net energy
7. ______ A(n) ______ absorbs and stores heat from the sun directly within a structure. a. active solar heating system b. passive solar heating system
passive solar heating system
11. ______ What is the world's fastest growing source of energy? a. solar power b. wind power c. hydroelectric power d. fuel cell power
possibly nonrenewable
1. ______ Which of the following is a by-product of burning hydrogen, taken from water, as a fuel? a. water vapor b. carbon dioxide c. methane d. deuterium
water vapor
10. ______ Which form of power has more advantages and fewer disadvantages than any other energy source? a. wind power b. solar power c. fuel cell power d. hydrolectric power
wind power
What is the difference between passive and active solar heating? What is the "payback time" for passive solar?
• A passive solar heating system absorbs and stores heat from the sun directly within a well-insulated structure without the need for pumps or fans to distribute the heat. An active solar heating system uses energy from the sun by pumping a heat-absorbing fluid through special collectors usually mounted on a roof or on special racks to face the sun. • Payback time for passive solar homes is 3-7 years
