Unit VII Energy What is energy? Energy is the ability to do work and transfer heat. It comes in many forms: Energy Terms Kinetic Energy Matter that has energy because of its mass and speed. Electromagnetic Spectrum Heat Temperature Energy Terms Potential Energy Stored energy that has the potential to do work. High quality energy Low quality energy Energy Terms Entropy Measurement of the disorder of energy. Higher entropy = less useful Physical Change Chemical Change Energy Terms Nuclear Change Nuclei of certain isotopes change into one or more different isotopes. Radioactive Decay Radiocarbon dating Energy Laws 1 st Law of Thermodynamics (AKA: Law of Conservation of Energy) So why worry about the loss of resources? 2 nd Law of Thermodynamics Developed vs. Developing Usage Energy Resources Where do we get our energy from? World Nonrenewable resources Renewable resources US (the largest user of energy) Nonrenewable resources Renewable resources US Energy Usage (2011) US Energy Efficiency & Sustainability 1.Increase Energy Efficiency and Conservation a. Requires many unpopular decisions i.Decrease speed limits ii. Eliminate government subsidies 2.Secure Future Fossil Fuel Energy Supplies a.Oppositions: i.environmental and economic 3.Develop Alternative Energy Sources a.Who pays for this? b.Gas taxes? 4.Meet the First Three Objectives Without Further Damage to the Environment Energy Cost Comparison Energy Resources Basic Power Production How do we make electricity??? Most power plants, no matter what type of fuel source utilized, create electricity in the same basic manner. Basic Coal-Fired Power Plant Non-Renewable Energy Fossil Fuels Most widely used source of energy in developed countries. Derived from decomposition of buried plant and animal matter trapped under high temperature & pressure for millions of years. Oil & Natural Gas Coal Coal Worlds most abundant fuel Composed primarily of carbon Coal Formed in several stages Coal Coal Reserves Coal Production Coal How do we extract coal? Subsurface Mining Used for coal reserves deep underground Traditional mines Very expensive and dangerous but less environmental damage Surface Mining used for coal nearer the surface causes the most environmental damage Area strip mining Contour strip mining Open Pit Mining Mountain Top Mining Coal Surface Mining Control and Reclamation Act (1977) Requires filling (reclaiming) of surface mines after mining Reduces Acid Mine Drainage Requires permits and inspections of active coal mining sights Prohibits coal mining in sensitive areas Coal Coal Burning: Releases large quantities of CO 2 into atmosphere Greenhouse gas Releases other pollutants into atmosphere Can cause acid precipitation Coal Can reduce air pollutants using: electrostatic precipitators scrubbers fluidized bed boilers Coal Pros Cons Crude Oil/Petroleum Primary Oil Recovery Secondary Oil Recovery Primary + Secondary Recovery Tertiary Oil Recovery Crude Oil/Petroleum Various Derivatives Refining process separates various hydrocarbons based on boiling points. Common derivatives Crude Oil/Petroleum Petrochemicals By-products of distillation process include components used in: Crude Oil/Petroleum Oil Reserves & OPEC Top Proven Oil Reserves Crude Oil/Petroleum Top Oil Producing Countries 1989 Alaskan Oil Spill Exxon Valdez hit a reef and spilled 260,000 barrels of crude oil into sound Largest oil tanker spill in US history Keystone Pipeline Crude Oil/Petroleum Pros Cons Natural Gas What is it? Primarily Methane (CH 4 ) Can also include other heavy gaseous hydrocarbons Conventional Natural Gas Unconventional Natural Gas Natural Gas LPG vs. LNG Liquefied Petroleum Gas Liquefied Natural Gas Natural Gas Top Proven Natural Gas Reserves Top Natural Gas Producers Natural Gas Pros Cons Synfuel Include: Length of Supplies??? Difficult to determine and estimates vary Depends on: Experts indicate there may be shortages in 21 st century Fracking Process of extracting Natural Gas and/or Oil from shale rock deep underground. Involves injecting a mixture of water and chemicals underground to break up the rock Global fracking projects have dramatically increased in the last decade (especially in US) Can be devestating to the surrounding environment Nuclear Energy Very expensive and complicated technology. Nuclear Fission Reactors atoms of Uranium-235 or Plutonium-239 are split by neutrons which releases energy (heat) entire reaction occurs in a moderator controlled by using neutron absorbing control rods Nuclear Energy Nuclear Fuel Cycle Processes involved in producing the fuel used in nuclear reactors and in disposing of radioactive (nuclear) wastes Nuclear Energy 441 commercial reactors in 32 countries producing 15% of the worlds electricity. 60 new reactors currently under construction 104 reactors in the US producing ~20% of our electricity. Moratorium on new plants began in1979. New ones have been approved and construction has begun however, including one in FL France heavily relies on nuclear energy ~77% of Frances power generation Heavily subsidized by the government Nuclear Energy Meltdown 3 Mile Island most serious reactor accident in US 50% meltdown of reactor core Elevated public apprehension of nuclear energy Chernobyl worst accident in history 1 or 2 explosions destroyed the nuclear reactor Spread across large portions of Europe Nuclear Energy Low-level radioactive waste High-level radioactive waste Mill Tailings Radiation in Perspective Nuclear Energy Long term storage of nuclear waste is an ongoing, global problem Nuclear Energy US currently stores wastes at temporary facilities Nuclear Energy Long term storage was planned for Yucca Mountain. Project has been canceled environmental concerns $$$ Nuclear Energy Licensed to operate for 40 years Power plants cannot be abandoned when they are shut down Three solutions Nuclear Energy Nuclear Fusion Fuses two atoms of hydrogen isotopes Havent been able to efficiently fuse atoms Nuclear Energy Pros Cons Renewable Energy What are they and where do they come from? Sources of energy that are potentially sustainable because it can last indefinitely without reducing the original supply. Solar Power The sun is the ultimate source of energy for the earth. Photovoltaic Cells Solar Power Active Solar Heating Traditional Electricity Production Solar Power Passive Solar Heating Solar Power Pros Cons Biomass Can be any organic material burned Heavily used in developing nations Also used to create electricity Can be converted into biofuels Biomass Pros Cons Wind Worlds fastest growing energy resource Winds are harnessed by building turbine farms in suitable locations. Best available sites to harness wind in US are the Great Plains states. Largest users of wind power is Northern Europe and the US Wind Pros Cons Hydropower 3 methods of electricity production: Large-scale Small-scale Pumped-storage hydropower Hydropower Chinas 3 Gorges Dam Hydropower Supplies ~20% of the worlds electricity Can be high or low quality depending on the situation. Pros Cons Hydropower Wave Energy Converts wave energy into electricity Pros Cons Geothermal Enormous potential energy source From Hydrothermal Reservoirs Geothermal From hot, dry rock Geothermal heat pumps Geothermal Currently used by 24 countries Pros Cons Tidal Energy Converts tidal energy into electricity Pros Cons Fuel Cell Device that directly converts chemical energy into electricity Fuel Cells Hydrogen and oxygen gases combine to produce electricity. H combines with O 2 in the air and produces water vapor Pros Cons Micropower Proponents argue the future will be decentralized small-scale micropower systems. Produce smaller amounts of electricity on site and disperse any excess to the traditional electrical grid.
