Presentation on theme: "Fossil Fuels Many power plant use steam to turn generators. Water is heated by burning fossil fuels or through nuclear reaction, and when the water boils,"— Presentation transcript:
Many power plant use steam to turn generators. Water is heated by burning fossil fuels or through nuclear reaction, and when the water boils, steam is produced. The steam is then fed through the turbines, forcing them to rotate. Energy Production using Steam
Fossil Fuels… … include coal, oil (from petroleum/crude oil), natural gas, tar sands, and oil shale. … formed over a period of time from compressed vegetation and other organisms. … are considered nonrenewable resources. Why?
Coal Coal is the most abundant and least expensive of the fossil fuels. It is also the most popular, accounting for almost 40 per cent of the total worldwide power generation.
Coal is a rock consisting almost entirely of organic material
The great coal forests Todays coal formed from prehistoric vegetation that accumulated thousands of years ago when much of the Earth's surface was covered in swamps. As the plants and trees in these swampy areas began to die, their remains sank into the swamp land, which eventually formed a dense material called peat. During this time there were huge forests of mosses, horsetails, and tree ferns
Peat – an early step in coal formation photo by: dModer101
A good place to look for peat formation … Peat only forms where there are low oxygen conditions, such as in this damp low spot on a swamp or bog. Bodies dont decay in bogs very well – as you can tell! Bog Man by: saamiblog by: LonePine
The Coal Formation Process … The organic matter accumulates and forms a bed of peat. The peat bed gets buried by other sediments and under heat and pressure begins to transform to a low grade coal known as lignite. More heat and pressure further change the lignite into bituminous coal. Even more heat and pressure change the bituminous coal into a nice hard shiny anthracite coal.
The Steps of Coal Formation…
U.S. Coal Deposits …
Is coal being made now? Coal formation is a continuing process, however large deposits of sediment are no longer covering swamp lands as in the past! Today, in areas such as the Great Dismal Swamp of North Carolina and Virginia, the Okefenokee Swamp of Georgia, and the Everglades in Florida, plant life decays and subsides, eventually to be covered by silts and sands, and other matter. Perhaps many years from now, those areas will contain large coal beds. The Florida Everglades by: Surrealplaces
Coal Mining … 2 main methods of coal mining: Underground Surface –strip mining –mountaintop removal (a new type of mining)
Coal mining has always been a dirty, dangerous job.
A coal seam exposed by mining
Strip mining coal
Mountaintop Removal – a large scale type of coal mining What effect does this type of mining have on the environment? by : Mr. Stabile
Health and environmental impacts of using coal as an energy source Surface mining requires the removal of massive amounts of top soil, leading to erosion, loss of habitat and pollution. Underground mining causes acid mine drainage, which causes heavy metals to dissolve and seep into ground and surface water. Coal mine workers also face serious health problems, including black lung, a lung disease from prolonged exposure to coal dust in mines. On the job hazards include: the mines may cave in, accumulate poison gases, or suddenly flood – all of which can injure or kill the miners
More Environmental Impacts of Using Coal … Burning coal creates ground level ozone, smog and acid rain. Coal (and fuel oil) combustion emit fly ash particles into the atmosphere, which contribute to air pollution problems. Burning coal produces carbon dioxide, nitrogen oxide, sulfur dioxide and methane gas, all of which could contribute to global climate change. Burning Coal is also the greatest producer of airborne Mercury pollution. hvo.wr.usgs.gov
Natural Gas… A natural gas well by: United States Government Work
Natural gas … Formed from the remains of tiny sea animals and plants that died thousands of years ago. (Same process that formed petroleum.) The gas became trapped in the rock layers much like a wet household sponge traps water. Raw natural gas is a mixture of different gases. Its main ingredient is methane. By itself, methane is odorless, colorless, and tasteless. As a safety measure, natural gas companies add a chemical odorant (it smells like rotten eggs) so escaping gas can be detected.
Processing natural gas … After natural gas comes out of the ground, it goes to a processing plant where it is cleaned of impurities (water, sulfur, dust) and separated into its various components Then its compressed and forced through pipelines under high pressure. Its often cooled to a liquid state before being transported. LNG – liquified natural gas A natural-gas processing plant by: A guy with A camera
Benefits of using natural gas … Cleaner fuel than petroleum or coal Has the highest energy content of the hydrocarbons used for fuel Our country has large reserves, mostly in the Gulf of Mexico, Texas, Louisiana, Oklahoma, New Mexico, Wyoming, Kansas, and Alaska. Used for making plastics, detergents, drugs But, if we continue to use natural gas at the same rate as we use it today, the United States will run out in about 50 years (more can be recovered for higher cost).
Other sources of natural gas Landfills - Landfill gas is considered a renewable source of natural gas since it comes from decaying garbage. –Landfill gas is 50 percent methane Biomass - a fuel source derived from plant and animal wastes which generates natural gas There are more than 350 commercial landfill gas recovery operations in the U.S. which generate electricity on-site, supply industrial gas-fired boilers, or produce substitute natural gas fuels such as CNG. by: Wisconsin Department of Natural Resources
Some landfills are currently capturing the gas produced by decaying garbage. A well is drilled into the waste mass in order to install a well. The landfill gas is then pumped to a gas treatment and processing facility to separate out the methane from carbon dioxide and other non-methane compounds. by: Wisconsin Department of Natural Resources
Study Reveals Huge U.S. Oil Shale Field … WASHINGTON The United States has an oil reserve at least three times that of Saudi Arabia locked in oil-shale deposits beneath federal land in Colorado, Utah and Wyoming, according to a study released yesterday. Headline from The Seattle Times, September 1, 2005 As the head of Shell's Unconventional Resources unit, Steve Mutt, explained that as far back as the native Americans, people have been trying to exploit this resource, which is essentially immature petroleum. The Indians called it fire rock and inexperienced homesteaders tried to use it for their fireplaces with disastrous consequences.
An oil-shale rock burns on its own once it has been lit by a blowtorch. by: asia blues
Oil shale doesnt contain oil or (usually) shale The organic material is kerogen (not oil), and the "shale" is usually a relatively hard rock, called marl. Properly processed, kerogen can be converted into a substance somewhat similar to petroleum. The kerogen must be heated to a high temperature. This causes the organic material to be converted into a liquid. The liquid is then further processed to produce an medium grade oil which is said to be better than the lowest grade of oil.
Heres the down side……. The report also says oil-shale mining, above-ground processing and disposing of spent shale cause significant adverse environmental impacts. Shell Oil is working on a process that would heat the oil shale in place, which could have less effect on the environment.
A new oil shale method uses in-ground heaters to preheat the oil shale so it is easier to remove the oil. Instead of strip- mining the rock and then processing it, this new method superheats huge underground areas for several years, This method gradually forces the oil out of the stone and then pumps it to the surface by: SkyTruth
Tar sands (also called oil sands or bituminous sands) These sands contain clay, water, sand, and bitumen Bitumen contains 83.2% carbon This can be processed to make synthetic crude oil or be refined into petroleum products. This may prove to be a viable alternative to oil imported from the Middle East. by: The Co-operative
Environmental impacts of using shale or tar sands Takes lots of energy to remove and process. Uses large amounts of water which is then polluted by the process. Generate huge amounts of waste that must be put back somewhere (unless the in-ground heating method is used). by: coopfs
Environmental Impact of Tar Sands Alberta Tar Sands The term tar sands refers to thick oil called bitumen that is mixed in with sand, clay, and water. Intensive energy is required to process the sands into crude oil. Tar Sands oil is the worlds most harmful type of oil for the atmosphere, emitting high volumes of greenhouse gases during development, which contribute to global warming, as well as other pollutants. Tar Sands projects are the largest contributor to greenhouse gas emissions growth in Canada. By 2015, the Tar Sands are expected to emit more greenhouse gases than the nation of Denmark (pop. 5.4 million).
Summary of Fossil Fuels … Petroleum Coal Natural Gas Oil Shale Tar Sands How much longer will we have access to these fuels? How expensive will they get as demand exceeds supply? What are some alternative energy sources?
Nuclear Energy Produces Electricity…
Two ways that nuclear energy can be produced are fusion and fission. Fusion – the combining of atomic nuclei – such as in the stars (and sun!) – generates energy Nuclear Energy
Fission – the breaking apart of atomic nuclei hyperphysics.phy-astr.gsu.edu/hbase/nucene/im... Nuclear Energy
Two advantages of nuclear energy: It produces huge amounts of energy from small amounts of nuclear fuel (uranium and plutonium). Earth contains enough nuclear fuel to meet all present and future needs. Nuclear energy
Nuclear Energy Nuclear energy produces wastes in the form of heat and spent (used) fuel – which can remain radioactive for thousands of years. Disposing of this radioactive spent fuel is a major problem. One proposed disposal site is Yucca Mountain in Nevada.
Nuclear Energy Four reasons why nuclear power is not as widely used as it could be… –High cost –Peoples fear of exposure to radiation –The threat of a meltdown (nuclear explosion) –The fear that nuclear weapons could be developed using this technology Stable, highly centralized governmental control is necessary for the safe operation of nuclear power.