Energy II

All of the energy which we use comes from the sun. Hydroelectric energy is possible because the sun causes water to evaporate and rise into the air. In the air it forms clouds. When the water concentration in clouds becomes very heavy, it falls as rain. The run off of rain water is then used to turn the turbines which generate electricity.

The energy of the wind can be used to turn wind turbines or windmills. Wind is produced by the sun heating air. When one area is warmer than another, wind will blow from the warm area to the cooler area.

Green plants have a chemical called chlorophyll. Chlorophyll traps the energy of the sun. Plants use this trapped energy to convert carbon dioxide and water into glucose. We consume this glucose either directly by eating green plants, or indirectly by eating animals which feed on green plants. This is how we get the energy to live.

Some of the sun's energy used by some plants (trees) is converted to wood. Wood can be burned to produce heat energy to do such things as keep us warm or to cook food.

The energy stored in fossil fuels, such as coal, oil or natural gas originally came from the sun. Fossil fuels come from the remains of dead plants and animals that lived at least 350 million years ago. In tropical swamps, ferns and mosses died and fell to the bottom of the swamp in layers. As things piled up on top of this dead mass, pressure and heat drove off the hydrogen and oxygen, leaving only carbon. This pure carbon is coal.

There are several different types of coal. Anthracite coal is the best grade of coal. Anthracite is the best fuel of all the coals because it has the highest energy content. The primary impurity in coal is sulfur; and anthracite coal contains the least amount of sulfur of all coals. Bituminous coal is somewhat lower in energy than is anthracite. Bituminous coal contains more sulfur than any other type of coal. Therefore, when bituminous coal is burned it releases more pollution than any other form of coal. Lignite coal has the lowest energy of all the coals, but it contains very little sulfur.

Crude oil (petroleum) and natural gas (methane) have similar origins, and therefore, they are usually found together. Crude oil and natural gas were formed from the remains of sea organisms which died and sank to the bottom of the sea and became covered by sand and mud. Heat, pressure and the action of bacteria converted these remains into oil and natural gas.

Coal, oil and natural gas are considered nonrenewable resources because they are being used at a faster rate than they can be formed. If the world's human population continues to grow, and if the demand for fossil fuels keeps increasing, we will eventually run out of fossil fuels. And both of these will, in all probability, grow.

It took from the beginning of human life to the year 1850 for human population to reach one billion. Eighty years later in 1930, human population had doubled to two billion. By 1975, it was four billion. And in 1999 the human population reached eight billion. Each year, we discover more and more things to make out of fossil fuels. Presently, some of the things which fossil fuels are used to make include: waxes, creosote, tar, asphalt, diesel fuel, kerosene, ether, naphtha, gasoline, solvents, ink, lacquers, dyes, neoprene, synthetic rubber, polyvinylchloride, plastics, synthetic fibers for clothes, detergent, epoxy, alcohol, and fertilizers. In addition, third World nations are rapidly becoming industrial and will require more fossil fuels to run their industry.

The single largest use of fossil fuels is in agriculture. 15% of the total energy used in America goes into agriculture. It takes 90 gallons of gasoline to run a tractor and the other equipment needed to raise one acre of corn. Fertilizers and pesticides are made from crude oil. Crude oil fuels the truck, ships and trains that carry food to market. As world population increases, so will the use of fossil fuels. We are destined to run out of these fuels.

In addition to running out of fossil fuels, there are other problems associated with these fuels. The recovery, processing and burning of fossil fuels produces potentially serious environmental problems. One of these problems is the pollution of aquifers.

Aquifer are underground pockets of water in permeable rock, sand or gravel that is used as a water supply for people. The strip mining of coal, creosote plants and refineries produce poisonous chemicals which get into this ground water. Because this has increasingly occurred, water well testing and safe bottled water has become big business.

The exhaust emissions from burning fossil fuels is a problem, and potentially could become an even more serious problems. In history you may have learned of the brain damage suffered during the Roman Empire when they used lead plumbing pipe and lead drinking containers. Today some studies indicate that 20% of all American children have abnormally high levels of lead in their bodies. It is known that lead can produce hyperactivity, attention deficit, and brain damage. In cities such as Mexico City, where they still used leaded gasoline, the mental damage from lead is even greater. The burning of fossil fuels is believed to be the primary cause of acid rain. The release of gases made from fossil fuels, such as Freon, is believed to be causing the disappearance of the ozone layer which protects the human body from the sun's ultraviolet radiation. All of these things makes it a good idea to explore alternative, renewable energy sources.

Wood is a renewable energy source. Modern wood burning stoves which circulate the heat can be an alternative source of fuel to heat homes. However, the traditional fireplace is a very inefficient and often counterproductive way of using wood to produce heat. 90% of all heat produced by a traditional fireplace goes out the chimney. Often as the heat rushes up the chimney it sucks all the hot air from the house and sends it up the chimney as well.

However, if a Franklin-type stove, or a fireplace insert, is added to the fireplace, it improves the efficiency. These stoves are made of iron which absorbs and radiates heat into the room. This increases the efficiency of the fireplace from 10% to about 40%. If the wood burning stove or fireplace insert has a circulation system, it increases the efficiency even more.

Synthetic fuels are liquid and gaseous fuels made from sources other than crude oil. Examples are ethanol and methanol. Ethanol and methanol are alcohols which are made from vegetation such as wood, corn, grains, or sunflowers. These alcohols can be made from any form of vegetation which is plentiful. These alcohols are made by microorganisms fermenting the sugar of the vegetation and converting it to alcohol. Ethanol is drinking alcohol. Methanol is commonly distilled from wood and is called wood alcohol.

Ethanol is used to make gasohol. Gasohol is 10% ethanol added to 90% gasoline. It cuts the amount of fossil fuel used to make gasoline by 10%. Crops such as sorghum and sugar cane convert more solar energy into potential fuel than any other plant. Countries such as Brazil use these crops to make ethanol, and require that cars be converted to be able to burn pure ethanol. Methanol can be used all by itself as a motor fuel. Methanol is presently used as fuel for many race cars. Methane (natural gas) can be made synthetically from coal and manure.

Another alternative fuel is oil shale. In Colorado, Wyoming and Utah are huge deposits of oil shale. Oil shale is rock that burns. It is formed from sediments of once living organisms and contains a waxy substance called kerogen. Kerogen produces an oil that can be used in place of crude oil. However, at the present time it is much more expensive to get oil from shale than to pump crude oil. New methods of extracting oil from shale may make this an economical alternative in the future.

A similar source of oil is tar sand. Tar sand is found in both the United States and Canada. However, like oil shale, it is very expensive to make oil from tar sand at the present time.

Another potential source of fuel is biomass. Biomass is the remains, waste or by-products of living things. Biomass consists of any kind of vegetation, food processing wastes, manure or garbage. If biomass could be efficiently converted to fuel it would solve two problems: it would be a good alternative fuel source, and it would solve the problem of disposing of solid waste. Biomass can be converted to fuel in two ways: by heating it in a furnace, and by fermentation by bacteria. In fermentation, the bacteria would convert the biomass to methane. A potentially good source of biomass is ocean kelp, which exists in great abundance. Another alternative fuel is the electrochemical cell. The electrochemical cell is already used to make batteries. Battery powered cars are not that far in the future. Both General Motors and Honda have prototypes on the market now. It has become fuel efficient to make and operate a battery powered car. Due to improved technology, battery operated cars now save more in fuels than they use in fuels to make and recharge their batteries. Even better than battery operated cars would be electric motorized cars powered by the fuel cell. As improvements are made in the fuel cell, electric cars will become more powerful and more efficient. Fuel cells, as you might remember, are electrochemical cells in which some of the materials which react are supplied from outside the cell. These materials are hydrogen and oxygen. So fuel cells are electrochemical cells which use hydrogen and oxygen to produce electricity. Hydrogen is oxidized and oxygen is reduced to produce a flow of electrons. The electrolyte which produces this movement of electrons from hydrogen to oxygen is potassium hydroxide. Electric motors powered by fuel cells are quiet and non-polluting. Their only exhaust is the water which is made as a by-product. Fuel cells could also be a good source of electricity for homes.

Another alternative energy source that we could make greater use of is nuclear fission. Nuclear power plants, like Waterford III, use nuclear fission to produce the heat used to heat water to produce the steam used to power the turbines which generate electricity. Fission is the splitting of the nucleus into two or more smaller nuclei. A neutron is shot at the nucleus of uranium 235 splitting it into barium 144 and krypton 90. When fission occurs, energy is released from the nucleus of the uranium 235. As fossil fuels become less plentiful nuclear fission could be used increasingly as a substitute for burning fossil fuels to generate electricity. If used safely, this would be a clean alternative to the use of fossil fuels. However, the problem remains of how to dispose of the hazardous nuclear waste.

Another potential alternative energy source is nuclear fusion. Fusion is the energy released when two or more nuclei join. The energy of the sun is the energy of nuclear fusion. On the sun, two hydrogens are fused to form helium. The drawback to using fusion is that at the present time, fusion requires very high temperatures. If "cold" fusion could be accomplished it could be the answer to almost all of the world's energy needs.

The ultimate answer to the world's energy needs will be the sun. The amount of solar energy striking the Earth is thousands of times greater than the world's energy needs. In addition, the sun's energy is constant, clean and free. The problem which faces us is how best to collect this energy and to store it.

Passive solar energy is energy obtained from sunlight without the use of pumps or motors to aid the flow of heat. Presently, passive solar energy is utilized by sky lights, by attaching a greenhouse to a living space, and by constructing solar hot water heaters.

Active solar energy is a system that collects and stores energy from the sun and uses a fan or a pump to circulate heated air or water. An active solar hot water heater uses a pump to pump the hot water into an insulated tank for storage. An active solar heating system would use a fan to circulate the hot air radiating from pipes containing water heated by the sun's energy. It is also possible to generate electricity using solar power. Solar generated electricity involves using mirrors to concentrate the sun's heat so that water can be heated to over 500 degrees Celsius. This produces the steam which is used to turn the turbine which generates electric current.

Solar cells are used to directly convert solar energy into electricity. Solar cells are made of selenium, germanium or silicon. Selenium, germanium and silicon are elements which release electrons when light strikes them. Presently experimentation is being conducted to use solar cells to power cars and light aircraft.

As fossil fuels begin to run out we could make more use of hydroelectric power. Hydroelectric power is the use of falling water to generate electricity. Hydroelectric power plants can be built by damming up a river to control the water which falls in a spillway. Hydroelectric power plants can also be built using natural water falls such as Niagara Falls. Presently, 14% of electric power in the United States comes from hydroelectric plants. Hydroelectric power plants are efficient and non-polluting. Once a hydroelectric power plant is in place, there is almost no cost for this energy. However, to make a hydroelectric power plant can be difficult. Often entire valleys are flooded to make the reservoir of water needed to turn the turbines. This wastes land and displaces people. Natural falls, such as Niagara, lose some of their beauty when a power plant is placed upon them.

Another potential alternative energy source is wind energy. Wind is created by the unequal heating of the Earth's surface. Historically, people have used the energy of the wind to sail boats, grind grain and pump water. In windy areas more and more people are using a wind turbine to generate electricity. Some homeowners can supply their complete electrical needs using a wind turbine, and they can sell any excess electric power to the power companies. They have meters which show how much electricity they put into the companies power lines and, by law, the power companies must pay them for this electricity.

Geothermal energy is energy from the hot core of the Earth. If an aquifer is located near a geothermal hot spot, the water may become so hot that hot water and steam shoot up from the ground. When hot water and steam shoot up from an aquifer located near a geothermal hot spot it is called a Geyser. The energy from this hot water and steam can be used to turn the blades of a turbine to generate electricity. This is known as a geothermal power plant. Geothermal power plants can be situated on a natural geyser, or wells can be drilled in known hot spot to create a geothermal power plant. There is a large geothermal power plant north of San Francisco and there are several in Iceland.

Another potential alternative energy source is tidal energy. The gravitational attraction between the Earth and the moon cause the level of sea water to rise and fall. This action is known as tides. If a dam is made in a river or canal close to the ocean, water can be trapped during high tides and released during low tides. The release of water could be used to power a turbine to generate electricity.

As we replace fossil fuels with alternative fuels we can buy more time by conserving energy and building more fuel efficient machines. In the average American family the automobile is the single largest consumer of energy. Ways that we can conserve and use less energy in our cars include: slowing down, making cars lighter in weight, have our engines properly tuned, changing our spark plugs and air filters, balancing our wheels, aligning the front end of our car, properly inflate our tires, car pooling, using public transportation, and by using the air conditioner in our cars only when it is needed. However, it is more efficient to use the air conditioner than to roll down windows, as rolled down windows create resistance which slows the car down.

In our homes, heating and cooling account for 60% of our energy use. To save energy at home we could: close unoccupied rooms, properly insulate our homes, add weather stripping to doors and windows, install storm windows (windows with two panes having dead air space between them), lower the temperature on hot water heaters, insulate hot water heaters, change the filter in furnace and air conditioning systems, cover pots and pans when cooking food in the summer, open the refrigerator door only when necessary, turning off lights, replacing incandescent light bulbs with fluorescent bulbs, buying clothes which can be washed in cold water and that do not need ironing, and by knowing how to calculate energy use by using power ratings when buying appliances.

To save energy we should recycle whenever possible. It takes less energy to recycle than to manufacture from raw materials. It takes 70% less energy to make steel from recycled scrap iron than from iron ore. It takes 95% less energy to make aluminum cans from recycled cans than from bauxite. It takes 40% less energy to make paper from recycled paper than from pulp wood. It takes 75% less energy to make glass from recycled bottles than from sand.

Cars can be designed to be more aerodynamic. This is being done today using lasers and computer models. The use of aluminum or ceramic to make engines reduces the size and weight of the engine. Fuel injection and turbo charging uses gasoline more efficiently that does a carburetor. Computer monitoring systems which monitors engine efficiency and which adjusts fuel injectors can also make

cars more fuel efficient.

Energy II Study Sheet