Near the town of Price, Utah. Energy sources come in a variety of forms (barrels of oil, tons of coal, etc.) Quad: a unit of energy used to compare different.
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Energy sources come in a variety of forms (barrels of oil, tons of coal, etc.) Quad: a unit of energy used to compare different types of energy sources The quad is based on the BTU (British thermal unit). 1 BTU is the energy needed to increase the temperature of 1 pound of water by 1 o Fahrenheit. 1 quad = 10 15 BTUs (1,000,000,000,000,000 BTUs) The United States uses about 100 quads of energy per year. World consumption of energy is about 400 quads The United States uses a fourth of the world’s energy consumption
Estimate of the Earth’s non-renewable energy resources (not reserves) (360,000 quads total) Enough for 900 years? Most of our non-renewable energy resources are in the form of uranium!
Throughout industrial history, the types of fuel that we mainly use have changed Pre-industrial – wood and animals Early industrial – coal Present day – oil, natural gas, and coal
Fossil Fuels (coal, oil, gas) 85% of the world’s current energy usage comes from fossil fuels. Energy is conserved (its neither created or destroyed), so where does the energy released from coal, oil, and gas come from?
Fossil Fuels (coal, oil, gas) 1. Sunlight creates organic matter by photosynthesis. Essentially: Water + carbon dioxide + energy (sunlight) = sugar (organic matter) + oxygen The opposite is also true: When we burn organic matter by adding oxygen: water, carbon dioxide, and energy are released.
1. Sunlight creates organic matter by photosynthesis. 2. Organic matter (e.g. vegetation) eventually dies, and some of this matter is preserved and buried in sedimentary rocks. After living things die, most of the organic matter combines with oxygen and decays. However, if conditions are right, some of this organic matter may be preserved: Swamps and coastal regions where There is lots of organic matter being created (lots of vegetation and life) There is very little or no oxygen at the bottom where dead things settle.
1. Sunlight creates organic matter by photosynthesis. 2. Organic matter (e.g. vegetation) eventually dies, and some of this matter is preserved and buried in sedimentary rocks. 3. As organic matter is buried, high temperatures, high pressures, and chemical reactions transform the organic matter to coal, oil, and gas. Whether organic matter turns into coal, oil, or gas depends on the type of organic matter and the environmental conditions. Gas and oil are buoyant liquids – they rise to the surface unless they are blocked by a “trap” oil and gas can permeate through sandstones but not shales almost all traps involve oil and gas being blocked by shale
Anticlinal trap – oil and gas are trapped beneath shale in an anticline
Fault trap – a fault moves a shale layer such that it blocks oil and gas from rising
Stratigraphic trap – formed by a sedimentary sequence in which a dipping sandstone layer thins out against a shale.
Salt dome trap – buoyant salt layers rise up to form an anticline in a shale layer
Oil 65% of oil reserves are in the Middle East (you don’t need to know the numbers in this figure except for 65% in Middle East)
Oil The United States uses about 18 million barrels of oil a day We produce about 8 million barrels a day We import about 10 million barrels a day The United States oil reserves are currently 23 billion barrels At this current rate, we have enough reserves for 8 years, meaning that we will have to 1.Rely more upon importation of oil 2. Expand reserves by New technologies – making currently unprofitable deposits profitable Open up oil fields that are currently protected 3. Replace oil with alternative fuels (coal, natural gas, hydrogen, solar, …)
Natural Gas Natural gas is mostly methane ( CH 4 ) Natural gas burns cleaner than oil or coal but still releases carbon dioxide United States reserves of natural gas should last about 10 years, but these reserves are expected to increase because of expectation of new gas field discoveries.
Coal Coal is mainly made of organic material from wetland vegetation (swamps). This vegetation gets buried and cut off from oxygen. Peat: organic matter composed of twigs, roots, and other plant parts. As peat is buried, it is heated and compressed, and chemical reactions increase the carbon content. Grade of coal Peat (lowest grade, lowest carbon content) Lignite Bituminous coal Anthracite (highest grade, highest carbon content)
Coal Nations with the most coal reserves: Russia, China, and the United States United States reserves should last hundreds of years. Reasons why coal is not the ideal fossil fuel choice: Strip mining leads to unsightly landscape Underground mining is dangerous Coal produces ‘ash’ which contains abundant Sulfur. (Sulfur in the atmosphere leads to Acid Rain) Burning of coal increases CO 2 in the atmosphere We can reclaim landscapes, improve safety measures in mines, and reduce ash emissions, however, these measures are costly and increase the price of coal.
Coal In the Unites States, we have Eastern and Western coals. Western coals are cleaner (have less sulfur), however, transportation costs are higher because most industry and population is in the east.
Coal In the eastern United States, most coal was formed in swamps near the foothills of the Appalachians (~300 million years ago) during the formation of Pangea.