Presentation on theme: "Mrs. Paul Environmental Science Pgs 234 - 249. Many forms of energy to meet the needs of people on Earth. Heat, light, energy, mechanical energy, chemical."— Presentation transcript:
Many forms of energy to meet the needs of people on Earth. Heat, light, energy, mechanical energy, chemical energy, nuclear energy. Energy cannot be created or destroyed, only changed from one form to another.
Example: Energy from the sun converted to chemical energy stored in plants. When you eat, the stored energy is converted to heat, mechanical energy, and chemical energy used to carry out life processes. Food is a form of fuel that your body uses for energy.
Called organic fuels. Contain carbon-based molecules formed by living things as well as carbon. Hydrocarbon: compound made of only carbon and hydrogen. Example: methane, ethane, octane Many organic fuels contain other chemicals as well (considered to be impurities in fuel).
Fuel: any substance from which energy can be obtained. Fossil fuel: remains of ancient organisms that changed into coal, oil, or natural gas. Central to life in modern societies. 2 main problems: 1. supply of fossil fuel is limited. 2. obtaining and using them causes environmental problems.
5 main purposes of fuels: 1. cooking 2. transportation 3. manufacturing 4. heating and cooling buildings 5. generating electricity to run appliances. How suitable the fuel is depends on: Energy content, cost, availability, safety, and byproducts of use.
Energy in fuel often converted into electrical energy to power machines. More convenient to use than coal, etc. How is electricity generated? Electric Generator: machine that converts mechanical energy (motion) into electrical energy. Do this by moving electrically conductive material inside a magnetic field.
Most electric generators convert the movement of a turbine into electrical energy. Turbine: wheel that changes the force of a moving gas or liquid into energy that can do work. Usually, steam turns the turbine.
World Patterns People in developed societies use more energy than people in developing countries. Differences within developed countries too. Ex: Canada/US uses 2x that of Japan or Switzerland. Energy Use in the United States Uses more energy than all except Canada and United Arab Emirates. Uses more than 25% to transport goods and people by truck and personal vehicle. Lowest fuel cost = little incentive to conserve. Japan and Switzerland have minimal fossil fuel and supplement with other energy sources.
Coal Formation Forms from remains of plants that lived in swamps Much in US formed 320 to 300 million years ago (vast swampland covered eastern US). Coal in western US only 100 – 40 million years ago. Ocean levels rose and fell = swamps covered with sediment. First forms Peat: brittle, brown plant material containing a great deal of water and low percentage of carbon. Layers of sediment compress the peat into lignite: soft, brown coal composed of about 40% carbon; it burns quickly and gives off little smoke. Sediment compressed plant remains and heat and pressure within Earth’s crust caused coal to form.
Oil and Natural Gas Formation Result from decay of tiny marine organisms that accumulate on bottom of ocean millions of years ago. Remains buried by sediments and heated = became complex energy-rich carbon-based molecules. Molecules migrated into porous rocks.
Most of fossil fuel reserves made of coal. ½ of electricity in US comes from coal fired plants Advantages: Inexpensive Need little refining after mining.
Coal Mining and the Environment Underground = minimal effect at surface. Surface mining Remove top of entire mountain to reach coal. Toxic chemicals can leach into nearby water sources. Air Pollution High grade coal produces less pollution and more heat. Ex: bituminous coal: soft coal located deep in Earth’s crust Anthracite coal: metamorphic rock made when extreme pressure and heat act on bituminous coal. Clean-burning and almost smokeless; fewest impurities of all coal. Low grade coal produces more pollution and less heat Ex: lignate
Petroleum: oil that is pumped from the ground, aka crude oil. Petroleum product: anything made from crude oil. Ex: fuels, chemicals, plastics Accounts for 45% of world’s commercial energy use. Nonrenewable resource.
Locating Oil Deposits Found in and around geologic features (folds, faults, salt domes) that trap oil as it moves in Earth’s crust. Exploration wells drilled to determine volume and availability of deposit. Wells drilled and oil pumped or flows to surface. Oil transported to refinery to convert to fuel and other petroleum products.
Natural Gas 20% of nonrenewable energy comes from natural gas. Methane Recovered from many oil wells. Produces fewer pollutants than other fossil fuels.
Fossil fuels supply 90% of the energy used in developed countries. It is projected that by 2050, our energy needs will have DOUBLED. Predicting Oil Production Still increasing, but slowly. Factors considered in oil predictions: Oil Reserves: oil deposits that can be extracted profitably at current prices using current technology.
Some oil deposits have not been discovered or become commercial. Changes in technology to allow more oil to be extracted. Relative cost of obtaining oil. Future Oil Reserves Geologists predict that oil production from fields accessible from land will peak in 2010. Additional oil under ocean floor = more expensive.
The Environmental Effects of Using Oil Pollution released into the air. Contribute to formation of smog and cause health problems. Carbon Dioxide released may contribute to global warming. Oil spills
Biomass Fuels: a fuel formed from the products of living organims. Ex: wood, garbage, methane, alcohol. Renewable resources Garbage The materials you throw away; composed mostly of organic material. 2/3 of material in it can be burned; some cities burning garbage to generate electricity.
Methane Swamp gas produced in swamps from decaying plants. A naturally produced form of methane. Alcohol Bioconversion: conversion of organic materials into fuels. A hydrocarbon in which one of the hydrogens is replaced with an oxygen-hydrogen group.