1. Why is energy efficiency an important energy resource ?
1.1. Energy efficiency
1.1.1. a measure of how much useful work we can get from each unit of energy we use. Roughly 84% of all commercial energy used in the United States is wasted.
1.1.2. Improving energy efficiency: quickest, cleanest, and usually the cheapest way to provide more energy.
1.2. Cogeneration
1.2.1. use a combined heat and power system to recycle steam as heat.
1.2.2. Three ways to save energy and money
1.2.2.1. Electric car motors
1.2.2.2. Recycle materials
1.2.2.3. Improve designs of data centers
1.3. Energyefficient smart electrical grid
1.3.1. an energy-efficient, digitally controlled, ultra-high-voltage (UHV) system with superefficient transmission lines. Connect solar and wind power to grids.
1.3.2. Three ways to save energy and money in transportation
1.3.2.1. higher gasoline taxes
1.3.2.2. building or expanding mass transit systems
1.3.2.3. encourage bicycle
1.4. Distinguish
1.4.1. Hybrid car: small, traditional gasoline-powered engine and a battery-powered electric motor.
1.4.2. Plug-in hybrid electric vehicle:travel 48–97 kilometers (30–60 miles) on electricity alone.
1.4.3. All-electric: cars are high because of the high cost of their batteries.
1.4.4. Fuel cell—a device: uses hydrogen gas (H2) as a fuel to produce electricity.
1.5. Four ways to save energy
1.5.1. In new buildings: Build facing sun to use solar power, Green architecture, Green roofs, Superinsulation.
1.5.2. In existing buildings: Insulate buildings/plug leaks, Use superinsulation, Heat water by tankless hot water systems.
1.6. Why we are still wasting so much energy and money ?
1.6.1. Lack of public education about energy use
1.6.2. Few, if any, economic incentives for encouraging energy efficiency
2. What are the advantages and disadvantages of using renewable energy resources ?
2.1. Rely on renewable solar and geothermal energy – why are we not using more ?
2.1.1. Government financial subsidies for research much less than those for fossil fuels
2.1.1.1. Subsidies must be renewed more often – resulting in political pressure possibilities
2.1.1.2. Free-market competition with fossil fuels does not include full-cost pricing
2.1.1.3. Transitioning from one type of fuel to another takes about 60 years
2.1.2. Passive solar heating system is without the use of mechanical devices, captures sunlight directly
2.1.3. Active solar heating system that uses solar collectors to capture energy from the sun and store it as heat for space heating and water heating.
2.1.4. Advantages
2.1.4.1. Medium net energy yield Very low land disturbance Moderate cost (passive)
2.1.4.2. Very low emissions of CO2 and other air pollutants
2.1.4.3. Moderate cost (passive)
2.1.4.4. Very low land disturbance
2.1.5. Disadvantages
2.1.5.1. Need access of sun 60% of time during daylight Need backup system for cloudy days
2.1.5.2. Sun can be blocked by trees and other structures
2.1.5.3. High installation and maintenance costs for active systems
2.1.5.4. Need backup system for cloudy days
2.2. Three ways to cool houses naturally
2.2.1. Block the high summer sun with shade trees, broad overhanging eaves, window awnings, or shades
2.2.2. In warm climates, use a light-colored roof to reflect as much as 90% of the sun's heat (compared to only 10-15% for a dark-colored roof), or use a green roof.
2.2.3. Use geothermal heat pumps for cooling (and for heating in winter)
2.3. Solar thermal systems that use any of various methods to collect and concentrate solar energy.
2.4. Photovoltaic (PV) cells: device that converts radiant (solar) energy directly into electrical energy. Also called a solar cell.
2.4.1. Advantages
2.4.1.1. Medium Net energy yield
2.4.1.2. Competitive cost for newer cells
2.4.1.3. Easy to install, move around, and expand as needed
2.4.1.4. Little or no direct emissions of CO2 or other air pollutants
2.4.2. Disadvantages
2.4.2.1. Need access to sun Solar-cell power plants could disrupt desert ecosystems
2.4.2.2. Some designs have low net energy yields
2.4.2.3. Need electricity storage system or backup
2.4.2.4. High costs for older systems but dropping rapidly
2.4.2.5. Solar-cell power plants could disrupt desert ecosystems
2.5. Hydropower is any technology that uses the kinetic energy of flowing and falling water to produce electricity. It is an indirect form of solar energy because it depends on heat from the sun. Besides that, the leading renewable energy source, produces about 16% of the world's electricity in 150 countries. According to the United Nations, only about 13% of the world's potential for hydropower has been developed.
2.5.1. Advantages
2.5.1.1. High net energy yield Large untapped potential Low-cost electricity Low emissions of CO2 and other air pollutants in temperate areas
2.5.2. Disadvantages
2.5.2.1. Large land disturbance and displacement of people High CH4 emissions from rapid biomass decay in shallow tropical reservoirs Disrupts downstream aquatic ecosystems
2.6. Wind power
2.6.1. in globally
2.6.1.1. Have been built on land in parts of Europe, China, and the United States. Wind power has been the world's second fastest-growing source of energy after solar cells. Around the world, more than 400,000 people are employed in the production, installation, and maintenance of wind turbines.
2.6.2. in the US
2.6.2.1. Texas is the nation's leading producer of electricity from wind power, followed by California. Wind power has more advantages and fewer serious disadvantages than all other energy resources except for energy efficiency
2.6.3. Advantages
2.6.3.1. Medium net energy yield Little or no direct emissions of CO2 or other air pollutants Easy to install, move around, and expand as needed Competitive costs for newer cells
2.6.4. Disadvantages
2.6.4.1. Need access to sun Some designs have low net energy yield Need electricity storage system or backup High costs for older systems but dropping rapidly Solar-cell power plants could disrupt desert ecosystems
2.7. Biomass
2.7.1. consists of plant materials that we can burn directly as a solid fuel or convert into gaseous or liquid biofuels, and it is another indirect form of solar energy.
2.7.2. Advantages
2.7.2.1. Widely available in some areas Moderate costs Medium net energy yield No net CO2 increase if harvested, burned, and replanted sustainably Plantations can help restore degraded lands
2.7.3. Disadvantages
2.7.3.1. Contributes to deforestation Clear-cutting can cause soil erosion, water pollution, and loss of wildlife habitat Can open ecosystems to invasive species Increases CO2 emissions if harvested and burned unsustainably
2.8. biodiesel and ethanol to power motor vehicles
2.8.1. Advantages
2.8.1.1. Reduced CO2 emissions for some crops Medium net energy yield for biodiesel from oil palms Medium net energy yield for ethanol from sugarcane
2.8.2. Disadvantages
2.8.2.1. Fuel crops can compete with food crops for land and raise food prices Fuel crops can be invasive species Low net energy yield for corn ethanol and for biodiesel from soybeans Higher CO2 emissions from corn ethanol
2.9. Geothermal energy
2.9.1. is heat stored in soil, underground rocks, and fluids in the earth's mantle. We can tap into this stored energy to heat and cool buildings and to produce electricity.
2.9.2. Advantages
2.9.2.1. Medium net energy yield and high efficiency at accessible sights Lower CO2 emissions than fossil fuels Low cost at favorable sights
2.9.3. Disadvantages
2.9.3.1. High cost except at concentrated and accessible sources Scarcity at suitable sights Noise and some CO2 emissions
2.10. Using hydrogen as a fuel to use in producing electricity and powering vehicles
2.10.1. Advantages
2.10.1.1. Can be produced from plentiful water at some sights No CO2 emissions if produced with use of renewables Good substitute for oil High efficiency in fuel cells
2.10.2. Disadvantages
2.10.2.1. Negative net energy yield CO2 emissions if produced from carbon-containing compounds High costs create needs for subsidies Needs H2 storage and distribution system
3. How can we make the transition to a more sustainable energy future?
3.1. Choosing Energy Paths
3.1.1. Choosing Energy Paths In considering possible energy futures, scientists and energy experts who have evaluated energy alternatives have come to three general conclusions.
3.1.2. First, during this century, there will likely be a gradual shift from dependence on nonrenewable fossil fuels to a mix of renewable energy from the sun, wind, flowing water hydropower, and the earths interior geothermal energy.
3.1.3. The use of renewable resources is already enabling many people to depend less on large centralized power systems and more on decentralized systems such as rooftop water heaters, single wind turbines, and solar cell panels.
3.1.4. Experts also project a shift from gasoline-powered motor vehicles to hybrid and plugin electric cars and perhaps to all-electric cars, if there are major improvements in battery technology.
3.1.5. The second general conclusion of experts about the future of energy use is that a combination of improved energy efficiency and carefully regulated use of natural gas will be the best way to make the transition to using mostly renewable energy resources during this century .
3.1.6. However, this will have to include much tighter controls on emissions of methane and other greenhouse gases throughout the entire natural gas production and distribution system
3.1.7. The third general conclusion is that because fossil fuels are still abundant and artificially cheap, we will continue to use them in large quantities.
3.2. Q&A
3.2.1. What is the key concept for this section? List three of the general conclusions of energy experts with regard to possible energy futures. List five major strategies recommended by such experts for making the transition to a more sustainable energy future
3.2.1.1. We can make the transition to a more sustainable energy future by greatly improving energy efficiency, using a mix of renewable energy resources, and including the environmental and health costs of energy resources in their market prices.
3.2.1.2. LIST 3 : -First, during this century, there will likely be a gradual shift from large, centralized macropower systems to smaller, decentralized micropower systems such as wind turbines, household solar-cell panels, rooftop solar water heaters, and small natural gas turbines. -The second general conclusion of experts about the future of energy use is that a combination of improved energy efficiency and carefully regulated use of natural gas will be the best way to make the transition to using mostly renewable energy resources during this century -The third general conclusion is that because fossil fuels are still abundant and artificially cheap, we will continue to use them in large quantities
3.2.1.3. LIST 5 : -increase fuel efficiency standards for vehicles, buildings, and appliances -reward utilities for reducing demand for electricity -greatly increase use of renewable energy -greatly increase renewable energy research and development -phase out coal subsidies and tax breaks
3.2.2. What are this chapter’s three big ideas? Explain how we can apply each of the six principles of sustainability in working to make a transition to a more sustainable energy future.
3.2.2.1. -We should evaluate energy resources on the basis of their potential supplies, their net energy yields, and the environmental and health impacts of using them. -By using a mix of renewable energy sources—especially solar, wind, flowing water, sustainable biofuels, and geothermal energy—we could drastically reduce pollution, greenhouse gas emissions, and biodiversity losses. -Making the transition to a more sustainable energy future will require sharply increasing energy efficiency, using a mix of environmentally friendly renewable energy resources, and including the harmful environmental and health costs of energy resources in their market prices
3.2.2.2. -relying much more on direct and indirect forms of solar energy for our electricity, heating and cooling, and other needs; -recycling and reusing more materials and thus reducing wasteful and excessive consumption of energy and matter -mimicking nature's reliance on biodiversity by using a diverse mix of locally and regionally available renewable energy resources.
4. WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF USING FOSSIL FUELS ?
4.1. Fossil Fuels Supply Most of Our Commercial Energy
4.1.1. Crude oil, or petroleum, is a black, gooey liquid contain- ing a mixture of combustible hydrocarbons (containing hydrogen and carbon atoms) along with small amounts of sulfur, oxygen, and nitrogen impurities It is also known as conventional or light crude oil
4.1.2. About 91% of the world’s commercial energy comes from nonrenewable resources—87% from carbon- containing fossil fuels (oil, natural gas, and coal) and 4% from nuclear power
4.2. Is the World Running Out of Crude Oil?
4.2.1. How much crude oil is there? No one knows, although geologists have estimated the amounts existing in identi- fied oil deposits. Available deposits are called proven oil reserves—deposits from which the oil can be extracted profitably at current prices using current technology. Proven oil reserves are not fixed
4.2.2. Advantages
4.2.2.1. Ample supply for several decades
4.2.2.2. Net energy yield is medium but decreasing
4.2.2.3. Low land disruption
4.2.2.4. Efficient distribution system
4.2.3. Disadvantages
4.2.3.1. Water pollution from oil spills and leaks
4.2.3.2. Environmental costs not included in market price
4.2.3.3. Releases CO2 and other air pollutants when burned
4.2.3.4. Vulnerable to international supply interruptions
4.3. Heavy Oils from Oil Shale and Tar Sand
4.3.1. A potential supply of heavy oil is shale oil—oil that is in- tegrated within bodies of shale rock
4.3.2. A growing source of heavy oil is tar sands, or oil sands, which are a mixture of clay, sand, water, and a combustible organic material called bitumen—a thick, sticky, tar-like heavy oil with a high sulfur content
4.3.3. Advantages
4.3.3.1. Large potential supplies Efficient distribution system in place
4.3.3.2. Easily transported within and between countries
4.3.3.3. Efficient distribution system in place
4.3.4. Disadvantages
4.3.4.1. Low net energy yield Severe land disruption and high water use
4.3.4.2. Releases CO2 and other air pollutants when produced and burned
4.3.4.3. Severe land disruption and high water use
4.4. Natural Gas
4.4.1. is a mixture of gases of which 50–90% is methane (CH4)
4.4.2. liquefied petroleum gas (LPG) : When a natural gas deposit is tapped, propane and butane gases can be liquefied under high pressure and removed
4.4.3. liquefied natural gas (LNG) : Natural gas can also be transported across oceans, by converting it to a high pressure and at a very low temperature
4.4.4. Advantages
4.4.4.1. Ample supplies Emits less CO2 and other air pollutants than other fossil fuels when burned
4.4.4.2. Versatile fuel
4.4.4.3. Medium net energy yield
4.4.4.4. Emits less CO2 and other air pollutants than other fossil fuels when burned
4.4.5. Disadvantages
4.4.5.1. Low net energy yield for LNG Production and delivery may emit more CO2 and CH4 per unit of energy produced than coal Fracking uses and pollutes large volumes of water
4.4.5.2. Potential groundwater pollution from fracking
4.4.5.3. Fracking uses and pollutes large volumes of water
4.4.5.4. Production and delivery may emit more CO2 and CH4 per unit of energy produced than coal
4.5. Coal
4.5.1. is a solid fossil fuel formed from the remains of land plants that were buried and exposed to intense heat and pressure for 300–400 million years
4.5.2. Advantages
4.5.2.1. Ample supplies in many countries
4.5.2.2. Low cost when environmental cost are not included
4.5.2.3. Medium to high net energy yield
4.5.3. Disadvantages
4.5.3.1. Severe land disturbance and water pollution
4.5.3.2. Emits large amounts of CO2 and other air pollutants when produced and burned
4.5.3.3. Fine particle and toxic mercury emissions threaten human health
5. What are the advantages and disadvantages of using nuclear power ?
5.1. How does a nuclear fission reactor work ?
5.1.1. To regulate the amount of power generated, plant operators use control rods, which move them in and out of the reactor core to absorb neutrons, thereby slowing or speeding up the nuclear reaction. lymph nodes
5.1.2. Coolant, usually water, circulates through the reactor core to remove heat and keep the fuel rods and other reactor components from melting and releasing large amounts of radiation into the environment school.
5.1.3. The LWR includes an emergency core cooling system as a backup to help prevent such crises.
5.2. What is the nuclear fuel cycle ?
5.2.1. Building and operating a nuclear power plant is only one part of the nuclear fuel cycle and If a reactor operates safely, the power plant itself has a fairly low environmental impact and the risk of an incident is very low. Considering the entire nuclear fuel cycle, the potential environmental impact will increase.
5.2.2. When assessing the safety, economic feasibility, net energy efficiency and overall environmental impact of nuclear power, energy experts and economists warn we should consider the whole nuclear fuel cycle, not just power plants.
5.3. Radioactive nuclear waste disposal is a difficult scientific and political issue
5.3.1. After a few years of cooling and some radioactive decay, they can be transferred to dry barrels made of heat-resistant metal alloys and concrete and filled with inert helium gas.
5.3.2. These bins are licensed for 20 years and can last for 100 years or more—a tiny fraction of the thousands of years that radioactive waste must be stored safely.
5.3.3. This reprocessing reduces the storage time for the remaining waste from 240,000 years (longer than the current human version) to about 10,000 years.
5.3.4. three ways
5.3.4.1. remove and store highly radioactive parts in a secure, long-term storage facility.
5.3.4.2. install a physical barrier around the plant and establish full-time security for 30–100 years, until the plant can be dismantled after its radiation levels reach a safer level.
5.3.4.3. The third alternative is to enclose the entire plant in a concrete and reinforced tomb, known as a containment structure.
5.4. Can nuclear power help slow the predicted climate change ?
5.4.1. Proponents of nuclear energy argue that by increasing the use of nuclear energy, we can significantly reduce CO2 emissions that are contributing to climate change.
5.4.2. While nuclear plants are operating, they do not emit CO2. However, in the 10 years it usually takes to build a plant, especially during the production of large quantities of construction cement, a large amount of CO2 is emitted
5.4.3. Every other step in the nuclear power fuel cycle also involves CO2 emissions. Such emissions are much lower than those from coal-fired power plants, but they still contribute to the warming of the atmosphere and projected climate change
5.5. Experts disagree on the future of nuclear energy
5.5.1. After nearly 60 years of development, huge financial investment and huge government subsidies, some 430 commercial nuclear reactors in 31 countries produce only 4% of commercial energy and 15% of electricity. world in 2012
5.5.2. In the United States, 100 licensed commercial nuclear power reactors generated approximately 8% of the nation's total energy and 19% of its electricity in 2012
5.5.3. This helps explain why nuclear power generation has essentially leveled off since 1985 and is now the world's slowest-growing commercial form of energy.
5.5.4. Critics argue that the most serious problem with the nuclear power fuel cycle is that it is uneconomical. They argue that the nuclear power industry cannot exist without a high degree of financial support from governments and taxpayers, due to the extremely high safety costs and low net energy efficiency of the cycle. nuclear fuel process
5.5.5. In the international market, the United States and 14 other countries have been selling commercial and experimental nuclear reactors and uranium fuel enrichment and refining technology for decades. The nuclear industry claims that hundreds of new advanced light water reactors (ALWRs) could be built in just a few years. ALWR has built-in safety features designed to make melting and release of radioactive emissions virtually impossible. The industry is also evaluating the development of smaller modular light water reactors—about the size of a school shuttle bus—that can be built in a factory, transported to one site and installed underground.