NaimExplain

Describe three negative environmental effects of dams on wild rivers. Answer: Damming a river destroys habitat for wildlife and disrupts natural flooding cycles that provide nutrient-rich sediment to floodplains. The changes in water depth due to damming creates temperature changes in the water that can destroy may fish populations - populations that are unable to handle the rapid and severe thermal shock when cold water is released from the dams.

Distinguish between the storage technique and the run-of-river techniques of hydropower. Answer: Storage technique. In this technique, river water is blocked behind dams, which store or impound the water. Water is then released through the dam and as it moves through, it turns blades of turbines, which in turn, generate electricity. Electricity from the dam is sent to an electric grid through transmission lines. By storing and controlling the water in this fashion, a steady supply of electricity can be maintained. Alternatively, a run-of-river approach, can be used which does not disrupt the flow of river water.

Tell how electricity is generated using hydropower. Answer: Kinetic energy of moving water is used to turn turbines and produce electricity. Two approaches are employed to harness the power of water.

Compare and contrast the use of ethanol and biodiesel. Answer: Ethanol is used in automobiles that burn gasoline and is produced by fermenting crops that are rich in carbohydrates. In fermentation, the carbohydrates are converted to sugars and then ethanol. Biodiesel is used in diesel engines and is produced from vegetable oils, primarily soybean oil in the U.S. In comparison with oil, biodiesel emissions are less, the fuel economy is almost as good, and it costs only slightly more than oil.

Tell the main characteristics of using biomass energy. Answer: Biomass is the organic matter that makes up living organisms. When this material is harvested and used to produce energy, it is called biomass energy. Biomass energy has many sources including wood, charcoal, and combustible animal waste

Define the term meltdown and contrast events at Three Mile Island and Chernobyl. Answer: Three Mile Island in Pennsylvania. In 1979, a combination of mechanical failure and human error resulted in leakage of coolant water from the reactor. This caused the reactor core temperature to elevate and the metal around the uranium fuel rods started to melt. This meltdown caused the release of radiation, most of which was trapped in the containment building.

Tell how electricity is generated using nuclear energy. Answer: Energy that holds protons and neutrons in the atom of a nucleus. Energy from atoms is collected by converting energy from an atom's nucleus into thermal energy by transforming isotopes of an element into isotopes of other elements. Splitting the nuclei of an atom and resultant conversion from nuclear to thermal energy is called nuclear fission.

Describe the need for energy conservation. Answer: Because the number of renewable energy sources is limited, it is essential to begin to minimize fossil fuel use by employing energy conservation strategies.

Define the term cogeneration. Answer: One way to improve power plant efficiency is to make use of cogeneration (a practice where heat that is generated through the production of electricity is captured and then used to heat workplaces and homes and provide other kinds of power).

Describe the environmental hazards associated with drilling for oil. Answer: In order to drill in an area, an infrastructure must first be created, including roads, housing, pipeline, and waste piles, to name a few. Because many oil reserves are located in areas where slow plant growth occurs, destruction of these plants can have a negative long-term impact on the ecosystem.

Discuss the controversy relating to drilling in ANWR. Answer: Much of the debate over whether to drill in the 1002 area of ANWR rests on the amount of economically recoverable oil, as it relates to world oil markets, weighed against the potential harm oil exploration might have upon the natural wildlife, in particular the calving ground of the Porcupine caribou.

Define the term acid drainage. Answer: Refers to the outflow of acidic water from (usually abandoned) metal mines or coal mines.

List and describe two negative effects of coal mining. Answer: Strip mining for coal destroys extensive areas of land and habitat and causes soil erosion and chemical runoff in a process called acid drainage.

Tell the energy recovery potential and environmental dangers of the following: Methane hydrates Answer: The ice-core methane clathrate record is a primary source of data for global warming research, along with oxygen and carbon dioxide.

Tell the energy recovery potential and environmental dangers of the following: Oil shale Answer: Shale oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly than the production of conventional crude oil both financially and in terms of its environmental impact

Tell the energy recovery potential and environmental dangers of the following: Oil sands Answer: Making liquid fuels from oil sands requires energy for steam injection and refining. This process generates 12 percent more greenhouse gases per barrel of final product than extraction of conventional oil

Define the term Hubbert's peak. Answer: Says that for any given geographical area, from an individual oil-producing region to the planet as a whole, the rate of petroleum production tends to follow a bell-shaped curve. It is one of the primary theories on peak oil.

Name five uses of petroleum products. Answer: Transportation fuels, fuel oils for heating and electricity generation, asphalt and road oil, and the feedstocks used to make chemicals, plastics, and synthetic materials

Distinguish between primary and secondary extraction of oil. Answer: Once oil deposits have been identified, exploratory drilling is conducted to determine the quantity of oil that may be available. Initial drilling and pumping of the oil (called primary extraction) is not very efficient, leaving as much as two-thirds of the oil in the ground and so secondary extraction is required which uses solvents or water to flush out the remaining oil.

List two ways that natural gas is formed. Answer: Natural gas is produced as a by-product when bacteria decomposes organic material under anaerobic conditions, producing primarily methane (CH4). Production of methane gas from decomposition of organic matter by bacteria in anaerobic conditions is called biogenic gas. Alternatively, natural gas can also be formed as the result of compression and heat deep underground. This is referred to as thermogenic gas.