559 Testing Your Comprehension
1.Fossil fuels are abundant on our planet today and can be used to create many sources of energy which is why they are so prevalent. They are considered nonrenewable sources of energy because they take millions of years to form and because humans are rapidly depleting our fossil fuels faster then they can be created, which makes these fuels nonrenewable. 2.Fossil fuels were formed from the tissues of organisms that lived 100-500 million years ago. The energy these fuels contain came originally from the sun and was converted to chemical-bond energy as a result of photosynthesis. Environmental conditions determine what type of fossil fuel is formed because of the chemical composition of the starting material, the temperatures and pressures to which the material is subjects, the presence or absence of anaerobic decomposers, and the passage of time. Fossil fuels are often concentrated in localized deposits because some regions have substantial reserves of fossil fuels whereas others have very few. 3.Net energy expresses the difference between energy returned and energy invested.
EROI is the ratio determined by dividing the quantity of energy returned from a process by the quantity pf energy invested in the process. These are important when evaluating energy sources because these ratios are always changing. 4.Coal is combusted and converted to water which turns to steam, this starts a turbine; this is how coal generates electricity. 5.Geologists have estimated the total amount of oil beneath the Arctic National Wildlife Refuge 1002 Area by drilling cores and conducting ground, air, and seismic surveys to map underground rock formations. This amount differs from the “technically recoverable” and “economically recoverable” because the “technically recoverable” ranges from 4.3-11.8 billion barrels, while the estimated amount ranges from 11.6-31.5 billion barrels. 6.We create petroleum products by refining hydrocarbon molecules that are separated into different size classes and are chemically transformed to create specialized fuels for heating, cooking and transportation, and to create lubricating oils, asphalts, and the production of plastics and other petroleum products. 7.Peak oil is when the rate of production of oil comes to its peak and begins to decline. Many experts believe we will soon pass the global production peak for oil because we are using it at a faster pace and are not finding new concentrations of oil.
If we do not shift to renewable energy sources, our society will meet its demise because we will run out of fossil fuels. 8.Fossil fuel production and consumption drive climate change, they pollute water as well as air, and they devastate natural systems. Drilling for oil in the Arctic National Wildlife Refuge would impact life in that area tremendously because that area would be quickly polluted and the wildlife would pay the price. Scientists are not even sure if this area has enough oil worth drilling for which is why it should not be touched. 9.An example of clean coal technology would be to use dry coal with high water contents. This approach would make is a cleaner-burning. Carbon capture technologies intend to remove carbon dioxide from power plants or other emissions, while carbon storage technologies try to sequester, or store, carbon dioxide from industrial emissions (underground under pressure in locations where it will not seep out). Both carbon capture and storage are in an effort to mitigate global climate change. 10.10. Two main approaches to energy conservation: as individuals, we can make conscious choices to reduce our own energy consumption by driving less, turning off lights when rooms are not being used, dialing down thermostats and cutting back on the use of energy-intensive machines and appliances. As a society we can conserve energy by making our energy consuming devices and processes more efficient. Consumers need to purchase energy efficiency appliances.
Pg 587 Testing your comprehension
1. Of our global energy they contribute: Nuclear 20.9 %; Hydro 2.2%; Bio 9.8%. Of our global electricity they generate: Nuclear 13.8%; Hydro 15.6%; Bio 2.6%. 2. Nuclear fission occurs when the nuclei of large, heavy atoms, such as uranium or plutonium, are bombarded with neutrons. Neutrons tend to move too quickly for their nuclei to split when they collide, so the neutrons need to be slowed down. Each split nucleus emits energy in the form of heat, light and radiation. It also releases multiple neutrons. These neutrons, bombard other nearby uranium-235 atoms, which result in a self sustaining chain reaction. Engineers control fission in nuclear reactors by using control rods, which absorb neutrons. They are placed into the reactor among the water-bathed fuel rods. The engineers move these rods into and out of the water to maintain the fission reaction at the desired rate.
3. In terms of greenhouse gas emission, nuclear, compared to coal, oil and natural gas, has less to none greenhouse emission. Hydropower and bioenergy compare 4. The incident at the Three Mile Island differed from that at Chernobyl because the Three Mile Island emergency was brought under control within days and the reactor was shut down quickly. This was due to a combination of mechanical failure and human error. The residents of the area were not as affected by the meltdown as those in Chernobyl. Chernobyl occurred because engineers had turned off safety systems to conduct tests, human error, and the unsafe reactor design caused an explosion. Many people were exposed to radiation; residents of the area were highly affected and till this day are still severely ill due to exposure. The accident killed 31 people. Radioactive fallout reached most of the Northern Hemisphere. 5. Some concerns about the disposal of radioactive waste are that if it’s dumped in the ocean it poses threat to fisheries, people and marine systems.
If it’s kept in the power plants, the power plants are running out of space to hold the waste. If it is sent to Yucca Mountain, while being transported there can be an accident that exposes people to the radioactive waste. As of now the waste is being kept in storage areas within the nuclear power plant. The United States chose Yucca Mountain as a place to dump the nuclear waste but so far the project has not taken place. The waste will remain in their current locations. 6. Sources for bioenergy include the waste products of existing industries or processes, residue from agricultural crops, animal waste and organic waste. Bioenergy use differs between developed and developing nations because 7. The two primary biofules are ethanol and biodiesel. Ethanol is the alcohol in beer, wine and liquor. It is produced by fermenting biomass. In fermentation, carbohydrates are converted to sugar and then to ethanol. Gasoline engines run with gasoline blended with 10% of ethanol. Biodiesel, a fuel produced from vegetable oil, used cooking grease or animal fat. It is also used in vehicles and can be mixed with conventional petrodiesel. In North America and in Europe, cars are being filled with biodiesel and some buses and recycling trucks as well.
8. Bioenergy is from carbon neutral which releases no net carbon into the atmosphereif bioenergy replaced the use of fossilfuels we could help mitigate the problems of climate change. Burning bioenergy is not carbon neutral for the fact that plants need to be cut down in order to plant bioenergy plants. 9. Storage type of hydroelectricity this type is the most widely used. It holds water back behind concrete dams that block the flow of water and just letting it flow out in smaller amounts through pipes that feed into a turbine. B. The other type of hydroelectricity generating plant is by implementing run-of-river approach.it generates electricity without greatly disrupting the flow of the river. Although it is not as damaging as damming the river, it doesn’t guarantee the same amount of water flow as by damming does. 10. two advantages with hydroelectric power are that the energy source is renewable and no carbon is emitted in the production of energy from this source. B. Two negative impacts of hydroelectricity is that the area behind dams are flooded destroying habitat and the areas below dams are usually starved of water. The other negative is the thermal pollution. Areas behind the dam gat colder that natural and the areas in front of the dam become warmer than natural.
Pg 614 Testing your comprehension
1.About 13% of our world’s energy is renewable and new renewable counts for 1%. The most prevalent form of renewable energy we use is biomass which accounts for 50% and hydroelectric which accounts for 35%. The form of energy most used to generate electricity is hydro power. 2.The diminishing amounts of fossil fuels have people concerned about our energy future. This is causing people to look for new renewable resources of energy. Solar and wind power are the new renewables that are experiencing the most rapid growth. 3.Passive solar heating is in the design of a building. It involves the installation of low south facing windows to capture sun, over hangs to shade windows in the summer, and the use of construction materials that capture the suns heat and release it throughout the day. Active solar heating is the use of technologies to heat water and air in structures.
It involves installing flat-plate solar collectors on rooftops. Water, air or antifreeze passes through the panel and gets heated by the sun which in-turns transfers its heat to the building or to water tanks. 4.The photoelectric effect is when light reaches the PV cell and strikes one of a pair which is made of the semiconductor silicone. The light causes one plate to release electrons which are attracted by electrostatic forces to the opposing plate. Photovoltaic cells work when you attach wires to the plates and allow the electrons to pass from one plate to the other freely. This causes an electric current or DC current which then can be converted to AC currents used in home and businesses. 5.Environmental and economic advantages of solar power are that the PV cells use no fuel, are quiet and safe, contain no moving parts, require little maintenance, and do not require a