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Earth Science

Ch. 25 Renewable energy

paty serrano

on 5 March 2012

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Transcript of Earth Science

Conventional energy
Ch. 25.2
Step 3
Ch. 25.3
The energy that humans and all other organisms use comes mostly from the Sun.
Humans use energy to keep them warm in cold climates, to cook food, to pump water, and to provide light. There are many different fuel sources available to humans to provide this energy. Most of these fuels also store energy that originated from the Sun.
Fuels are materials that are consumed to produce energy.
Muscle power from animals
Wind & water usage
Steam engines powered by wood fires
Steam engines powered by coal
Now we use oil more because it is easier to ship, store & burn.
Oil use peaked in 1979, so did prices thanks to Arab oil embargo & Iranian revolution.
1980’s began pursuing renewable energies but then oil prices fell and we went back to oil.
Primary Energy sources-
Fossil fuels (oil, natural gas, coal)
Nuclear energy
Falling water, geothermal, solar
Secondary Energy sources-
Sources derived from a primary source like…
Alcohol fuels (gasohol)
The total amount of living matter in an ecosystem is its biomass. Therefore, fuels derived from living things are called biomass fuels.
Biomass fuels are renewable resources.
Energy resources removed from the earth’s crust include: oil, natural gas, coal, and uranium
One type of fuel available for human use is derived directly from plant material. Plant materials burn readily because of the presence of hydrocarbons—molecules with hydrogen and carbon bonds only.
Humans have been using wood for fuel for thousands of years. Billions of people, mostly in developing countries of the world, use wood as their primary source of fuel for heating and cooking.
The simplest way to use field crops, such as corn, hay, and straw, as fuel is to burn them. Crop residues left after harvest, including the stalks, hulls, pits, and shells from corn, grains, and nuts, are other sources of energy.
Feces from cows often meet the energy needs of people in developing countries with limited forest resources.
Bogs are poorly drained areas with spongy, wet ground composed mainly of dead and decaying plant matter. Over time, as plant material in a bog is compressed by the weight of water and by other sediments that accumulate, it becomes a light, spongy material called peat.
Highly decomposed peat burns with greater fuel efficiency than wood.
Today, peat is used to heat many homes in Ireland, England, parts of northern Europe, and the United States.
Energy sources that formed over geologic time as a result of the compression and incomplete decomposition of plants and other organic matter are called fossil fuels
Fossil fuels are nonrenewable resources because their formation occurs over millions of years, but we are using them at a much faster rate.
Although fossil fuels are diverse in their appearance and composition, all of them originated from organic matter trapped in sedimentary rock.
Coal, formed from peat over millions of years, is the most abundant of all the fossil fuels. The greater the carbon concentrations in coal, the hotter it burns.
Coal forms from the compression of organic material over time.
Crude oil that is collected on Earth’s surface or pumped out of the ground is refined into a wide variety of petroleum products.
Natural gas forms along with oil and is found beneath layers of solid rock, which prevent the gas from escaping to Earth’s surface.
Crude oil and natural gas migrate sideways and upward from their place of formation.
Geologic formations such as faults and anticlines—folds of rock—can trap petroleum deposits.
Oil shale is a fine-grained rock that contains a solid, waxy mixture of hydrocarbon compounds called kerogen.
When kerogen vapor is extracted from oil shale, it can be condensed to form a heavy, slow-flowing, dark-brown oil known as shale oil.
Oil shale is found primarily in sedimentary rocks. One of the most abundant sources of oil shale known is the Green River Formation in Utah, shown as the dark green regions.
The U.S. has 1/20th (5%) of the world’s population (300 million people) but we consume 24% of the world’s energy
84% from fossil fuels (coal, oil, natural gas)
7% from nuclear power
9% from renewable resources (hydropower, geothermal, solar, and biomass).
66% is lost to thermal conversion when energy in coal is converted to electricity.
10% is lost when transmitted to you at home.
75% lost during distillation, transportation, storage, combustion in vehicles
10% lost in shipping & processing
Most efficient and least polluting (has more H than C so produces less CO2 when burned so contributes less to global warming.)
Nonrenewable fossil fuels (oil, coal, and natural gas) are used to generate approximately 85 percent of the total energy consumed for electricity, heat, and transportation in the United States. At current consumption rates, available oil and natural gas reserves might last only another 50 years.
Scientists, private companies, and government agencies are all studying renewable resources, such as solar energy, as alternatives to traditional energy resources, including fossil fuels.
Floors and walls made of concrete, adobe, brick, stone, or tile have heat-storing capacities and can help to hold thermal energy from the Sun inside a home.
Solar energy that is trapped in materials and slowly released is called passive solar heating.
Active solar-heating systems include collectors such as solar panels that absorb solar energy and fans or pumps that distribute the energy throughout a house.
A photovoltaic cell is a thin, transparent wafer that converts sunlight into electrical energy and is made up of two layers of two types of silicon.
Photovoltaic cells are reliable, quiet, and typically last more than 30 years.
Hydroelectric power is generated by converting the energy of free-falling water to electricity.
Today, hydroelectric power provides about 20 percent of the world’s electricity and 6 percent of its total energy.
Ocean water is another potential source of energy. The energy of motion in waves, which is created primarily by wind, can be used to generate electricity
Energy produced by Earth’s naturally occurring heat, steam, and hot water is called geothermal energy.
In areas where large amounts of geothermal energy are released, which usually coincide with plate boundaries, geothermal energy can be used to produce electricity.
Windmills in the Netherlands have been capturing wind power for human use for more than 2000 years.
Experts suggest that wind power could supply more than 10 percent of the world’s electricity by the year 2050.
Ethanol is a liquid produced by fermenting crops such as barley, wheat, and corn that can be blended with gasoline to reduce consumption of fossil fuels. Ethanol fuels burn more cleanly than pure gasoline.
Petroleum is the most widely used energy resource worldwide, followed closely by coal and natural gas.
Developing countries obtain 41 percent of their energy from a renewable resource, compared to industrialized countries where renewable resources account for only about 10 percent of the energy used.
Using renewable energy resources that are locally available conserves the fuel that would be used to transport and process resources at a different location.
Using a variety of energy resources rather than a single, nonrenewable energy resource can also help conserve resources.
Energy is the ability to do work. The amount of work produced compared to the amount of energy used is called energy efficiency.
Energy resources do not produce 100 percent of the potential work that is stored in the energy source.
Most of the electricity in the United States is generated by burning fossil fuels to heat water, forming steam. This is an inefficient process. Approximately one-third of the energy potential within the original fuel source can be converted into steam pressure.
Although most transportation currently relies on oil, conservation practices can help reduce dependency on oil resources used for transportation.
so, what can we do?
People who live in metropolitan areas can improve energy efficiency by using public transportation.
The use of fuel-efficient vehicles also reduces the amount of petroleum resources consumed.
Increased demand for fuels requires a greater supply and results in higher costs.
If energy were used more efficiently, less energy would be needed, thus decreasing the total cost of energy.

The simultaneous production of two usable forms of energy is called cogeneration.
While industries use one-third of all energy produced in the United States, cogeneration has allowed some industries to increase production while reducing energy use.
Sustainable energy involves global management of Earth’s natural resources to ensure that current and future energy needs will be met without harming the environment.
Global cooperation can help maintain the necessary balance between protection of the environment and economic growth.
Sustainable energy involves global management of Earth’s natural resources to ensure that current and future energy needs will be met without harming the environment.
Global cooperation can help maintain the necessary balance between protection of the environment and economic growth.
Read Ch. 25 section 1
When you finish, pick "Oil formation" WS
Due tomorrow.
Aluminum Foil
Black construction paper
Duct tape
Cotton balls
Plastic wrap
Straws -straight
Popsicle sticks
Paper clips
Paint brush
Paper bags
Butcher paper
Glue stick
*1 pizza box
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