4/14/2015. Bill Nye Video. Nonrenewable Energy Resources

Transcription

1 Bill Nye Video Nonrenewable Energy Resources 1

2 April 22, 1970 Several events in the 60 s prompted the creation. Well explosion off the coast of Santa Barbara CA in January, million gallons of crudes oil dumped. Our reliance on oil and other fossil fuels has only increased. Spills can happen during any part of the process: leaks, explosions, extraction, transport. March, 1989: Exxon Valdez super tanker crash into Prince William Sound, Alaska. 53 million gallons. April, 2010: BP Deepwater Horizon oil well in the Gulf of Mexico. Killed 11 workers, injured 17, 206 million gallons of oil dumped. 2005: BP oil refinery in Texas. 15 workers killed. April, 2010: Coal mine explosion in West Virginia. 29 miners killed. Most of our energy comes fro nonrenewable sources (sources that once they are used up, they cannot be replenished). Two main categories: Fossil fuels and Nuclear fuels. What affects the rate at which energy is used? Availability Affordability More recently, environmental impacts. In 2005, U.S. used 355GJ per person per year (5x greater than the world average) Overall, 20% of the world uses 70% of the energy! 2

3 Nonrenewable Energy Nonrenewable energy resources- fossil fuels (coal, oil, natural gas) and nuclear fuels. Annual consumption worldwide by resource. Fossil Fuel Video Energy Use Commercial energy sources- those that are bought and sold, such as coal, oil and natural gas. Subsistence energy sources- those gathered by individuals for their own use such as wood, charcoal and animal waste. 3

4 Up to 1875: wood predominant energy source. 1875: Coal came into wider use. Early 1900 s: oil and natural gas join coal as primary sources of energy. 1950: Nuclear enters the mix and hydroelectricity becomes more prominent s: decline in oil and resurgence of coal. Today (U.S. and worldwide): in order of increasing importance oil, coal, natural gas. Major outputs of energy use are work and waste (heat, CO 2, and other pollutants). Produces 70% of the energy it needs. 30% from other countries. Energy use varies both seasonally and regionally. Air conditioning/heating needs. The type of energy used is a function of many factors: ease of transport, amount of energy per mass of fuel, etc. 4

5 Central Case: oil or wilderness on Alaska s North Slope? Alaska s remote North Slope represents a pristine wilderness to some and untapped oil riches to others The Arctic National Wildlife Refuge is the focus of intense debate over whether the 1002 Area should be opened to drilling Opponents fear that drilling will sacrifice the nation s national heritage for little gain Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Alaska s North Slope consists of three regions The National Petroleum Reserve Alaska (NPR-A) - Intended to remain untapped unless the nation faced an emergency - It has been opened recently for drilling Prudhoe Bay consists of state lands that are drilled for oil that is transported via the trans-alaska pipeline to the port of Valdez The Arctic National Wildlife Refuge (ANWR) is federal land set aside for wildlife and to preserve pristine ecosystems - It has been called the Serengeti of North America Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 5

6 Alaska s North Slope Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Certain types of energy are better suited for particular jobs: Transportation: gasoline or diesel is preferred because it is a liquid source which is relatively compact meaning it has a high energy-to-mass ratio, they also provide or cut off the energy with great speed. Down side, they are bigger pollutants, require a great deal of refining, etc. One of the best ways to determine the best source for the job is to consider the energy efficiency. Second law of thermodynamics: as a source of energy is transformed its ability to do work diminishes. 6

7 Overall Fuel Efficiency of U.S. Automobiles EROEI (Energy return on energy investment) EROEI= Energy obtained from the fuel Energy invested to obtain the fuel **The bigger the EROEI, the better. 7

8 Process of Energy Use Public transportation is much more efficient than traveling by car (because most people travel alone). Car efficiency goes up as more people are added. In the United States vehicle choice plays an important role. Most do not choose by fuel efficiency alone but also by comfort, convenience and style. Recent legislation says that by 2016, the overall fleet average MPG must be at 35. 8

9 Sources of energy: Primary: coal, oil, and gas (burning at the source). Secondary: Electricity (obtained from the conversion of a primary source). Electricity is clean at the point of use but there are many pollution tradeoffs before that point. Greatest efficiency comes with the fuel that entails the fewest conversions from the original source. Electricity Generation 9

10 Electricity Generation The burning fuel from coal transfers energy to water, which becomes steam. The kinetic energy contained within the steam is transferred to the blades of a turbine, a large device that resembles a fan. As the energy in the steam turns the turbine, the shaft in the center of the turbine turns the generator. This mechanical motion generates energy. Energy Efficiency Most coal burning power plants are about 35% efficient. 10

11 Cogeneration Cogeneration- using a fuel to generate electricity and to produce heat. Example- If steam is used for industrial purposes or to heat buildings it is diverted to turn a turbine first. This improves the efficiency to as high as 90%. 11

12 Coal Coal- a solid fuel formed primarily from the remains of trees, ferns, and other plant materials that were preserved million years ago. Four types of coal ranked from lesser to greater age, exposure to pressure, and energy content. These four types are: lignite, sub-bituminous, bituminous, and anthracite. The largest coal reserves are in the United States, Russia, China, and India. Coal 12

13 Advantages and Disadvantages of Coal Advantages Energy-dense Plentiful Easy to exploit by surface mining Technological demands are small Economic costs are low Easy to handle and transport Needs little refining Disadvantages Contains impurities Release impurities into air when burned Trace metals like mercury, lead, and arsenic are found in coal Combustion leads to increased levels of sulfur dioxide and other air pollutants into the atmosphere. Ash is left behind Carbon is released into the atmosphere which contributes to climate change Petroleum Petroleum- a mixture of hydrocarbons, water, and sulfur that occurs in underground deposits. Oil and gasoline make this ideal for mobile combustion, such as vehicles. Formed from the remains of ocean-dwelling phytoplankton that died million years ago. Countries with the most petroleum are Saudi Arabia, Russia, the United States, Iran, China, Canada, and Mexico. 13

14 Petroleum Advantages Convenient to transport and use Relatively energy-dense Cleaner-burning than coal Advantages and Disadvantages of Petroleum Disadvantages Releases carbon dioxide into atmosphere Possibility of leaks when extracted and transported Deliberate and accidental releases of waste oil Possible that it might melt permafrost and interfere with the calving of caribou along pipelines Releases sulfur, mercury, lead, and arsenic into the atmosphere when burned 14

15 Natural Gas Natural gas- exists as a component of petroleum in the ground as well as in gaseous deposits separate from petroleum. Contains 80 to 95 percent methane and 5 to 20 percent ethane, propane, and butane. Largest uses are for electricity generation and industrial processes in the U.S. Also used for residential heating, clothes dryers, stoves, water heaters. Advantages and Disadvantages Natural Gas Advantages Contains fewer impurities and therefore emits almost no sulfur dioxide or particulates Emits only 60% as much carbon dioxide as coal Disadvantages When unburned, methane escapes into the atmosphere (potent greenhouse gas) Exploration of natural gas has the potential of contaminating groundwater Large quantities of water used during extraction 15

16 Other Fossil Fuels Oil sands- slow-flowing, viscous deposits of bitumen mixed with sand, water, and clay. Bitumen (tar or pitch)- a degraded type of petroleum that forms when a petroleum migrates close to the surface, where bacteria metabolize some of the light hydrocarbons and others evaporate. The Hubbert Curve Hubbert curve- a graph that shows the point at which world oil production would reach a maximum and the point at which we would run out of oil. He predicted in 1969 that 80% of world reserves would be used up within 60 years. 16

17 The Future of Fossil Fuel Use If current global use continues, we will run out of conventional oil in less than 40 years. Coal supplies will last for at least 200 years, and probably much longer. Technological advances in renewable energy will someday make oil less desirable. Uranium also offers a desirable alternative to fossil fuels and their negative affects on the environment and their release of greenhouse gases. 17

18 Often rejected because of concerns over the dangers of nuclear accidents, radioactivity, and weapons. Fission- a nuclear reaction in which a neutron strikes a relatively large atomic nucleus, which then splits into two or more parts. Nuclear Energy Nuclear Reactors Uses the same basic principles to create electricity as the coal plant except that a fission reaction (of U-235) provides the heat. 18

19 1 neutron U 142 Ba + 91 Kr + 3 neutrons Nuclear Reactors Fuel rods- the cylindrical tubes that house the nuclear fuel used in a nuclear power plant. Nuclear power plants work by using heat from nuclear fission to heat water. This water produces the steam to turn the turbine, which turns a generator. Control rods- cylindrical devices that can be inserted between the fuel rods to absorb excess neutrons, thus slowing or stopping the fission reaction. 19

20 Large commercial uranium mining operations exist in Australia, Western U.S., and parts of Canada. 70% of the electricity generated in France comes from nuclear and it has wide use in Lithuania, Germany, Spain, the UK, Japan, China and South Korea. The U.S. gets 20% of their electricity from nuclear. Currently 104 plants in the U.S. Advantages and Disadvantages of Nuclear Energy Advantages No air pollution is produced Countries can limit their need for imported oil Disadvantages Possibility of accidents Disposal of the radioactive waste Chernobyl and 3 Mile Island 20

21 Radioactive Waste High-level radioactive waste- the form used in fuel rods. Low-level radioactive waste- the protective clothing, tools, rags, and other items used in routine plant maintenance. Uranium mine tailings- residue left after uranium is mined and enriched. Radioactive Waste Radioactive waste- once the nuclear fuel can not produce enough heat to be used in a power plant but it continues to emit radioactivity. This waste must be stored in special, highly secure locations because of the danger to living organisms. Cannot be incinerated, disposed of using chemicals, shot into space, dumped on the ocean floor. Remains a threat for 10 half-lives (the accepted number by scientists). 21

22 Current disposal of spent fuel rods is on location. In 1978 the U.S. department of Energy began examining the Yucca Mountain site in Nevada as a permanent storage area. In 2006 the DOE released a report confirming the soundness of the site. A few years later after a presidential changeover, the project was cancelled. (Obama administration) Fusion Nuclear fusion- the reaction that powers the Sun and other stars. This occurs when lighter nuclei are forced together to produce heavier nuclei and heat is released. Fusion is a promising, unlimited source of energy in the future, but so far scientists have had difficulty cotaining the heat that is produced. 22

23 Achieving Energy Sustainability Moon Power More commonly known as Tidal Energy Uses the moon s gravitational force which interacts with Earth s to create tides twice a day near coastlines and near mouths of rivers. Kinetic energy of the moving water can be captured and converted into a usable form as the water flows through turbines in a similar way to windmills or large dams. Tides move in and out, so you can harness the energy in both directions. 23

24 RITE Project Roosevelt Island Tidal Energy Located in the East River in New York. Typical fossil fuel plant produces 500 MW. At full capacity, with 30 turbines, the RITE project will produce 1 MW. Does this however with little environmental impact: no water diversion, no dams for water storage, mesh enclosures protect fish, invisible from the shore, operates silently. Even though it will contribute only a small portion of our energy needs, it could be a part of a sustainable energy plan. What is renewable energy? Renewable energy can be rapidly regenerated, and some can never be depleted, no matter how much of them we use. Two types: Potentially renewable: wood and biofuel Nondepletable (no matter how much we use today it won t affect our tomorrow): wind, solar, hydroelectric, geothermal There are also nonrenewable resources (because we use them faster than they can replenish): Fossil fuels (coal, natural gas, petroleum/oil) and nuclear fuel. 24

25 World Ave. U.S. Energy In the U.S. about 7% of our energy comes from renewable energy. U.S. Average 25

26 How can we use less energy? Energy conservation- finding ways to use less energy. For example, lowering your thermostat during the winter or driving fewer miles. Energy efficiency- getting the same result from using a smaller amount of energy. A truly sustainable approach to energy must incorporate both! Using both are the least expensive way to for maximizing our energy needs and are fairly simple ways rather than conversion to a new system. Government Involvement What are some top down approaches to achieving sustainability? Improve the availability of public transportation Higher taxes to discourage excess use. Rebates or tax credits. Tiered rate system 26

27 Reducing energy use: There are many ways individuals can reduce their energy consumption. Benefits of Conservation and Efficiency Many energy companies have an extra backup source of energy available to meet the peak demand, the greatest quantity of energy used at any one time. Variable price structure- utility customers can pay less to use energy when demand is lowest and more during peak demand. Second Law of Thermodynamics: as energy is converted, it loses some of that energy as unusable heat So for us to reduce our electricity use by 100 KWh we may actually be conserving 300 KWh of energy resource such as coal. 27

28 Sustainable Design Improving the efficiency of the buildings we live and work in. Passive Solar Energy Using passive solar energy can lower your electricity bill without the need for pumps or other mechanical devices. Building the house with windows along a south-facing wall which allows the Sun s rays to warm the house would be an example. As would Window shades, using materials with a high thermal inertia, building into a side of a hill or a green roof, better insulation. 28

29 California Academy of Sciences Incorporates a variety of passive solar techniques: radiant heating, solar panels, skylights. Saves 30% on the energy it is actually allowed via building code. 29

30 BIOMASS Biomass is energy from the Sun The Sun is the ultimate source of almost all types of energy Biomass is energy from the sun. Most types of renewable energy are also derived from the sun and cycles driven by the sun. Biomass accounts for 10% of the world s energy consumption. Can be refined or processed into liquid fuel (biodiesel and ethanol: known collectively as biofuels) 30

31 U.S. Energy Consumption 0ther sources 96.5% 2/3 wood 1/6 msw Biomass 3.5% 1/6 biofuels 31

32 Modern Carbon vs. Fossil Carbon Many people are confused how burning biomass such as wood is better then burning coal. The carbon found in biomass was in the atmosphere as carbon dioxide, taken in by the tree, and by burning it we put it back into the atmosphere (it was taken out more recently) No net increase in Carbon (known as carbon neutral). Burning coal is carbon that has been buried for millions of years and was out of circulation until we began to use it. This results in a rapid increase in the concentration of carbon dioxide in the atmosphere. Biomass Wood, Charcoal and Manure- used to heat homes throughout the world. Removing timber faster than it can grow is a nonsustainable process. Leads to deforestation, may release carbon from the soil (deep in the a and b horizons), erosion, increased water temperatures in nearby rivers and streams, fragmentation of the forest habitats, may harm species that are reliant on old-growth forest habitat. Charcoal is lighter than wood and contains approximately twice as much energy per unit weight. In areas where wood is scarce, people often rely on animal manure. 32

33 Biofuels: Ethanol and biodiesel Ethanol and Biodiesel (biofuels)- used as substitutes for gasoline and diesel fuel. Ethanol is the same alcohol used in alcoholic beverages. More than 90% of the ethanol created in the US comes from corn and corn by-products. Biodiesel is a substitute for regular petroleum diesel. US government is encouraging use of Ethanol and Biodiesel as a way to relieve our dependence on foreign oil while supporting US farmers 33

34 U.S The US is the leader in ethanol production, manufacturing approximately 34 billion liters in (9 bill gal.) 2008 May, 2009-Barack Obama issued a directive to accelerate US investment in and production of biofuels. Brazil- second largest producer of ethanol (from sugarcane). Replanted only every 6 years and harvested by hand. Implications for greenhouse gas emissions? Gasohol Ethanol is usually 10% of a gas/ethanol mixture. Higher oxygen content than gasoline, so less pollution, but also gets less MPG. E-85: 85% ethanol/15%gasoline Flex-fuel vehicles Other possible alternative: Switchgrass (less sugars, needs more refining) or woodchips 34

35 Biodiesel A direct substitute for petroleum diesel. Typically diluted to B-20, a mixture of 80% petroleum/20% biodiesel. SVO:Straight Vegetable oil: made from waste vegetable oil that is strained and recycled in an SVO facility. Works with commercially sold kits. Most biodiesel comes from soybean oil or processed vegetable oil. Alternatives may be algae. The kinetic energy of water can generate electricity Hydroelectricity- electricity generated by the kinetic energy of moving water. This is the second most common form of renewable energy in the world. 7% of the electricity in the US more than ½ of this is in the states of CA, WA, OR China is the world s leader in hydroelectricity followed by Brazil and the US. 35

36 Captures kinetic energy and uses it to turn a turbine. Amount of electricity depends on the distance it falls or the flow rate or both. Types of hydroelectric power systems Run-of-the-river systems- water is held behind a dam and runs through a channel before returning to the river. Water impoundment- water is stored behind a dam and the gates of the dam are opened and closed controlling the flow of water. Tidal systems- the movement of water is driven by the gravitational pull of the Moon. 36

37 Is hydroelectric sustainable? Dams are expensive to build, however Minimal amount of fossil fuels. Large quantities of electricity without air pollution, waste products, Co2 emissions. Less expensive for the consumer. Can provide recreational and economic opportunities in the reservoir behind the dam. Downstream flood control. (Three Gorges Dam) Downsides of Hydro Three Gorges Dam: Displaced 1.3 Million people, submerged ancient cultural and archaeological sites as well as large areas of farmland. Impounding water makes it unsuitable for organisms that depend on free flowing which is colder and more oxygen rich. Some human parasites become more abundant. Sandbars are created. Migration patterns/life cycles are disrupted. 37

38 Capturing the sun s Energy The Sun s energy can be captured directly Solar energy: dependent upon cloudiness, time of day, season and geographic location. Passive solar heating-no pumps or mechanics to move the heat. Active solar energy- capturing the energy of sunlight with the use of a pump or photovoltaic cell and generating electricity. Solar water heating systems, photovoltaic systems (PV), Concentrated Solar thermal electricity generation (CST). 38

39 Solar water heating A solar domestic hot water system. A nonfreezing liquid is circulated by an electric pump through a closed loop of pipes. This circulating liquid moves from a water storage tank to a solar collector on the roof, where it is heated, and back to the tank, where a heat exchanger transfers the heat to water. Photovoltaic solar energy In this domestic photovoltaic system, photovoltaic solar panels convert sunlight into direct current (DC). An inverter converts DC into alternating current (AC), which supplies electricity to the house. Any electricity not used in the house is exported to the electrical grid. 39

40 Benefits and Drawbacks No air pollution No water pollution No CO2 production Produce electricity when it is needed most: hot sunny days. Initial cost to set up PV panels are expensive Manufacturing PV requires a great deal of energy and water and involves a variety of toxic metals and industrial chemicals. End-of-life reclamation of PV solar cells is a source of environmental contamination Life span <20-30 years 40

41 Earth s internal heat produces geothermal energy Geothermal energy- using the heat from natural radioactive decay of elements deep within Earth as well as heat coming from Earth. Wherever magma comes close enough to ground water, the ground water is heated. Where it does not rise to the surface naturally (Yellowstone geysers, etc.) humans may be able to reach it by drilling. US, China, and Iceland have substantial geothermal resources and are the largest producers of geothermal energy. Iceland: 87% of their home heating, 20% of it s electricity. US 5% of its renewable energy. Can be installed anywhere regardless of whether there is geothermal energy 41

42 Wind energy is the most rapidly growing source of electricity Wind energy- using a wind turbine to convert kinetic energy into electrical energy. Wind is a result of the unequal heating of Earth. Widely used in some countries and making a comeback in others. Wind energy capacity: Us has the largest capacity, followed by Germany, China, India, and Italy. US only produces 1% of its energy via wind. Denmark: largest user at 21% of their electricity Under average wind conditions: Wind turbine on land may produce electricity 25% of the time, creating 2,000-3,000kW (enough to supply 400 homes a year. 42

43 Funny comic I found Pros and cons For political and regulatory reasons it is most practical to have wind farms (or parks). Fastest growing source of electricity worldwide. Fossil fuels mostly only used during construction. No pollution, greenhouse gases. Can share land with other uses (farm, cattle land). Rely on batteries to store electricity. Noisy. Ugly??? Some say yes, others say no. Bird/bat migration and flying paths (40,000 birds per year in US) 43

44 FUEL CELLS Hydrogen fuel cells have many potential applications Fuel cell- a device that operates like a common battery where electricity is generated by a reaction between two chemicals. Main difference: In a fuel cell the reactants are added continuously, so the cell continues to provide energy as long as the fuel is added. 2H 2 + O 2 energy + 2 H 2 O Supplying Hydrogen is a challenge because free hydrogen is rare in nature and explosive. 44

45 80% efficient H2O only byproduct 45

46 Electrical grid The US electricity distribution system is outdated and subject to overloads and outages, which cost the US economy over $100 Billion per year. Scientists in the US maintain that because we do not have a cost-effective, reliable means of storing energy, that depending on intermittent energy sources would cause the grid to br risky and unstable. Smart grid Efficient, self-regulating electricity generating distribution source. Coordinates energy use with availability. Some experts maintain that a better system would consist of a large number of small scale electricity generating parks that rely on a mix of fossil fuel and renewable energy. Would save money because it would transfer energy over shorter distances leading to less loss (2 nd law of thermodynamics) and they would be safer from breakdown and sabotage. They would also cause less large scale outages. 46