Physics. Energy Lecture 2
TYPES OF ENERGY SOURCES
•When you use electricity in your home, depending on where you live, the electrical power was probably generated by burning coal, by a nuclear reaction, or by a hydroelectric plant at a dam. Therefore, coal, nuclear and hydro are called energy sources.•When we fill up a gas tank, the source might be petroleum or ethanol made by growing and processing corn.
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•An energy source is a raw material that is taken from the natural world and is used to produce one or more forms of energy.•These energy sources can be classified in two ways.
•One way of doing so is by grouping them into the traditional and non traditional sources. We call these the conventional and non-conventional sources.
•The other way of classification is— renewable (an energy source that can be easily replenished) and nonrenewable (an energy source that we are using up and cannot recreate).
•Renewable and nonrenewable energy sources can be used to produce secondary energy sources including electricity and hydrogen.
•We will use the second classification of Renewable and Non-renewable energy sources to look at some of the various energy sources we have.
TYPES OF ENERGY SOURCES
RENEWABLE
•Sun
•Wind
•Heat inside the Earth
•Biomass from plants
•Water behind a dam
NON RENEWABLE
•Fossil fuels
•Uranium
•We use renewable and nonrenewable energy sources to generate the electricity we need.
•We get most of our energy from nonrenewable energy sources:
–fossil fuels
•oil, natural gas, and coal.
–Uranium
(The nonrenewable energy sources are mostly the conventional sources of energy)
•Fossil fuels were formed many hundreds of millions of years ago before the time of the dinosaurs - hence the name fossil fuels. The age they were formed is called the Carboniferous Period.
•At the time, the land was covered with swamps filled with huge trees, ferns and other large leafy plants. The water and seas were filled with algae and diatoms.
•As the trees and plants died, they sank to the bottom of the swamps of oceans. They formed layers of a spongy material called peat.
•Over many hundreds of years, the peat was covered by sand and clay and other minerals, which turned into sedimentary rock.
•More rock piled on top of more rock, it began to press down on the peat. The peat was squeezed until the water came out of it and it eventually, over millions of years, it turned into coal, oil or petroleum, and natural gas.
•Coal is a hard, black colored
rock-like substance.
It is made up of carbon,
hydrogen, oxygen, nitrogen
and varying amounts of sulphur.
•There are three main types of coal:
–anthracite, (hardest, high in carbon giving it a higher energy)
–bituminous
–lignite (softest, low in carbon but high in hydrogen and oxygen)
•Coal is mined out of the ground using various methods.
–Some coal mines are dug by sinking vertical or horizontal shafts deep under ground, and coal miners travel by elevators or trains deep under ground to dig the coal.
–Other coal is mined in strip mines where huge steam shovels strip away the top layers above the coal. The layers are then restored after the coal is taken away.
•Coal is used to fuel power plants and other factories.
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•Oil is found under groundbetween folds of rock and
in areas of rock that are
porous and contain the oils
within the rock itself.
•To find oil, companies drill through the earth to the deposits deep below the surface. The oil is then pumped from below the ground by oil rigs.
•At oil refineries, crude oil is split into various types of products by heating the thick black oil.
•The products include gasoline, diesel fuel, aviation or jet fuel, home heating oil, oil for ships and oil to burn in power plants to make electricity.
•Natural gas is lighter than
air and is mostly made up
of a gas called methane CH4.
This gas is highly flammable.
•Natural gas is usually found
near petroleum underground. It is pumped from below ground and travels in pipelines to storage areas.
•Natural gas usually has no odor and you can't see it. Before it is sent to the pipelines and storage tanks, it is mixed with a chemical that gives a strong odor.
RENEWABLE - biomass
•Biomass:
–dead trees, tree branches
–yard clippings
–left-over crops
–wood chips and sawdust from lumber mills.
–Livestock manure.
•Waste is brought to a biomass power plant. Here the biomass is dumped into huge hoppers. This is then fed into a furnace where it is burned. The heat is used to boil water in the boiler, and the energy in the steam is used to turn turbines and generators
•Biomass can also be tapped right
at the landfill. When garbage or
animal waste products
decompose, it gives off
methane gas.
•Pipelines are put into the landfills
and the methane gas can be
collected. It is then used in power
plants to make electricity.
•It is then used in power plants to make electricity.
•This type of biomass is called landfill gas.
•Today, new ways of using biomass are still being discovered. One way is to produce ethanol, a liquid alcohol fuel. Ethanol can be used in special types of cars that are made for using alcohol fuel instead of gasoline. The alcohol can also be combined with gasoline.
RENEWABLE - Hydro
•The kinetic energy of
moving water can be
used to make electricity.
•Hydro means water.
Hydro-electric means
making electricity from
water power.
•Dams can be built to stop the flow of a river. Water behind a dam often forms a reservoir.
•Dams are also built across larger rivers but no reservoir is made. The river is simply sent through a hydroelectric power plant or powerhouse.
•The water behind the dam flows through the intake and into a pipe called a penstock. The water pushes against blades in a turbine, causing them to turn.
•The turbine spins a generator to produce electricity.
•solar
GREENHOUSE EFFECT, GLOBAL WARMING, AND ENVIRONMENTAL POLLUTION
•What is the Greenhouse effect?
•What is Global warming?
•Causes of these effects
•What is environmental pollution?
•What are the causes?
•What are the effects?
ENVIRONMENTAL POLLUTION
•What is environmental pollution?
–the contamination of the physical and biological components of the earth/atmosphere system to such an extent that normal environmental processes are adversely affected
–Pollution is the introduction of contaminants into the environment that cause harm or discomfort to humans or other living organisms, or that damage the environment” which can come “in the form of chemical substances, or energy such as noise, heat or light”. “Pollutants can be naturally occurring substances or energies, but are considered contaminants when in excess of natural levels.
–“Pollution is habitat contamination”
•In one word, environmental pollution takes place when the environment cannot process and neutralize harmful by-products of human activities (for example, poisonous gas emissions) in due course without any structural or functional damage to its system.
•Saving Fossil Fuels
•Fossil fuels take millions of years to make. We are using up the fuels that were made more than 300 million years ago before the time of the dinosaurs. Once they are gone they are gone.
•So, it's best to not waste fossil fuels. They are not renewable; they can't really be made again. We can save fossil fuels by conserving energy.
•Using biomass can help reduce global warming compared to a fossil fuel-powered plant. Plants use and store carbon dioxide (CO2) when they grow. CO2 stored in the plant is released when the plant material is burned or decays. By replanting the crops, the new plants can use the CO2 produced by the burned plants. So using biomass and replanting helps close the carbon dioxide cycle. However, if the crops are not replanted, then biomass can emit carbon dioxide that will contribute toward global warming.
•So, the use of biomass can be environmentally friendly because the biomass is reduced, recycled and then reused. It is also a renewable resource because plants to make biomass can be grown over and over.