Chapter 16 Energy Sources. Fossil Fuels Using Energy: Using Energy: – Transforming Energy: – The law of conservation of energy states that energy cannot.

Chapter 16

Energy Sources

Fossil FuelsFossil Fuels• Using Energy:Using Energy:– Transforming Energy:– The law of conservation of energy states that

energy cannot be created or destroyed. Energy can only be transformed from one form to another that can perform a useful function.

• Energy Use in the United StatesEnergy Use in the United States.– More energy is used in the United States than any

other country in the World.

Below is a graph of the sources of energy consumption in the U. S.

• Making Fossil Fuels:Making Fossil Fuels:– Fuels such as petroleum, or oil, natural gas, and

coal are called fossil fuels.fossil fuels.– Concentrated Energy SourcesConcentrated Energy Sources

• Petroleum:Petroleum:– Petroleum is formed by hydrocarbons (a hydrocarbon

is a compound made up of carbon and hydrogen) with the addition of certain other substances, primarily sulphur. Petroleum in its natural form when first collected is usually named crude oil, and can be clear, green or black and may be either thin like gasoline or thick like tar.

– Most people tend to believe that petroleum is mostly used to power internal combustion engines in the form of gasoline or petrol. Although our automobiles and other forms of transport do consume the highest quantity of petroleum it is used for a vast array of applications.

• PetroleumPetroleum is also a major part of the chemical makeup of many plastics and synthetics. Possibly the most startling usage of petroleum for many people is its appearance in foodstuffs such as beer and in medications such as aspirin.

• Natural gasNatural gas, in itself, might be considered an uninteresting gas - it is colorless, shapeless, and odorless in its pure form. Quite uninteresting - except that natural gas is combustible, abundant in the United States and when burned it gives off a great deal of energy and few emissions. Unlike other fossil fuels, natural gas is clean burning and emits lower levels of potentially harmful byproducts into the air.

• CoalCoal is a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons. It is the most abundant fossil fuel produced in the United States.

• Coal is a nonrenewable energy source because it takes millions of years to create. The energy in coal comes from the energy stored by plants that lived hundreds of millions of years ago, when the Earth was partly covered with swampy forests.

•Uses of Coal:Uses of Coal:About 93% of the coal used in the United States is used for generating electricity. Except for a small amount of exports, the rest of the coal is used as a basic energy source in many industries including steel, cement, and paper.

• Generating Electricity:Generating Electricity:– In the United States, most coal is used as a fuel to generate

electricity. Burning coal produces numerous emissions that adversely affect the environment and human health.

•Thermal Generating Plants:Thermal Generating Plants:Thermal plants use the energy of heat to make electricity. Water is heated in a boiler until it becomes high-temperature steam. This steam is then channeled through a turbine, which has many fan-blades attached to a shaft. As the steam moves over the blades, it causes the shaft to spin. This spinning shaft is connected to the rotor of a generator, and the generator produces electricity.

• Efficiency of Power Plants:Efficiency of Power Plants:– The concept of efficiency is a vital factor whenever one form

of energy is converted to another, as we need to do in areas such as coal liquefaction and hydrogen-powered vehicles. This page looks at this subject in more detail.

– Whenever energy is converted from one form to another, some of that energy is lost as heat – that is a basic law of thermodynamics. Efficiency is defined as:

• The efficiency of any energy conversion system is defined as the useful energy output divided by the total energy input. This is usually multiplied by 100 to give a percentage.

• The figures in brackets (shown graphically as orange stripes) are the theoretical output; the other figure (shown as red) is the output in practice. For example, if the coal that is burnt in a steam engine begins with, say, 100 joules of energy, then 95% of that energy is lost as heat and only 5 joules are left to do whatever work is intended.

• The Hidden Cost of Fossil Fuels The Hidden Cost of Fossil Fuels • Fossil fuels—coal, oil, and natural gas—are America's

primary source of energy, accounting for 85 percent of current US fuel use. Some of the costs of using these fuels are obvious, such as the cost of labor to mine for coal or drill for oil, of labor and materials to build energy-generating plants, and of transportation of coal and oil to the plants. These costs are included in our electricity bills or in the purchase price of gasoline for cars.

• America is overly reliant on fossil fuels such as coal, natural gas and oil. This dependence is costly to everyday citizens, and sends valuable dollars overseas and out of the domestic economy.

• But some energy costs are not included in consumer utility or gas bills, nor are they paid for by the companies that produce or sell the energy. These include human health problems caused by air pollution from the burning of coal and oil; damage to land from coal mining and to miners from black lung disease; environmental degradation caused by global warming, acid rain, and water pollution; and national security costs, such as protecting foreign sources of oil.

• Fossil fuel production and use damage our environment and our health – inflicting even greater damage on the American economy and our quality of life.

3. The economic and environmental burden of fossil fuel dependence will only worsen in the years to come.

4. Investing in clean energy that never runs out can reap economic savings. The United States has the ability today to produce this energy, and to help Americans use energy more efficiently in their homes, businesses and vehicles.

• Released by: Environment America • Release date: Tuesday, June 30, 2009

The federal government, along with the states, should take actions to reduce our dependence on fossil fuels. They should:

1. Reduce the nation’s emissions of global warming pollutants deeply enough to prevent dangerous impacts from global warming, guided by the latest scientific understanding.

2. Ensure that a cap-and-trade program used to achieve those targets directs the revenues gained through the sale of allowances for public purposes.

3. Ensure that America generates at least 25 percent of its electricity from renewable sources of energy such as wind and solar power by 2025.

4. Strengthen energy efficiency standards and codes for appliances and buildings5. Promote the development and implementation of clean transportation infrastructure6. Ramp up investment in solar power through tax credits, specific targets in state

renewable electricity standards, requirements for “solar ready homes,” rebate programs, and other measures.

7. End subsidies to fossil fuel industries.

Nuclear EnergyNuclear Energy• Using Nuclear Energy:Using Nuclear Energy:• Nuclear energy originates from the splitting of uranium atoms in a process

called fission. Fission releases energy that can be used to make steam, which is used in a turbine to generate electricity. Nuclear power accounts for approximately 19 percent of the United States' electricity production. More than 100 nuclear generating units are currently in operation in the United States. No nuclear power plants have been built since 1996

• Uranium is a nonrenewable resource that cannot be replenished on a human time scale. Uranium is extracted from open-pit and underground mines. Once mined, the uranium ore is sent to a processing plant to be concentrated into a useful fuel (i.e., uranium oxide pellets). This uranium enrichment process generates radioactive waste. Enriched fuel is then transported to the nuclear power plant.

• The core of a nuclear reactor contains both water and fuel rods made of zirconium and pellets of nuclear fuel, such as uranium, that set off a controlled nuclear reaction. The reaction, heats the water, creating 550-degree Fahrenheit steam, which powers a turbine, generating electricity.

• If a massive nucleus like uranium-235 breaks apart (fissions), then there will be a net yield of energy because the sum of the masses of the fragments will be less than the mass of the uranium nucleus. If the mass of the fragments is equal to or greater than that of iron at the peak of the binding energy curve, then the nuclear particles will be more tightly bound than they were in the uranium nucleus, and that decrease in mass comes off in the form of energy according to the Einstein equation. For elements lighter than iron, fusion will yield energy.

• Nuclear Power ProsNuclear Power Pros– The most obvious advantage of nuclear power is its incredible efficiency. One

ton of uranium can produce the same amount of energy as several million tons of either coal or petroleum. In terms of emissions, nuclear power is a much cleaner burning fuel than either coal or oil, and new generation reactors actually produce much less waste and have much higher safety controls compared to other power sources. In a world that is greatly concerned with global warming, the fact that nuclear power produces such little emissions is a tremendous benefit.

• Nuclear Power ConsNuclear Power Cons– The glaring issue associated with nuclear power, especially with the recent

issues in Japan and the renewed highlight on Chernobyl, is the idea of a possible nuclear meltdown or major radiation emission. There is a very real fear of nuclear meltdown, the process that occurs when the fission reaction is out of control.

– Another major drawback to nuclear power is the waste created in the process of creating energy. Nuclear waste must be contained and stored for thousands of years. This means that it creates waste that generations long after us will have to live with. Also, in an increasingly dangerous world, the idea that a nuclear plants or nuclear weapons could possibly be controlled by terrorists is cause for concern.

• Nuclear Fusion:Nuclear Fusion:– Fusion reactors have been getting a lot of press recently because they offer

some major advantages over other power sources. They will use abundant sources of fuel, they will not leak radiation above normal background levels and they will produce less radioactive waste than current fission reactors.

– Nobody has put the technology into practice yet, but working reactors aren't actually that far off. Fusion reactors are now in experimental stages at several laboratories in the United States and around the world.

– A consortium from the United States, Russia, Europe and Japan has proposed to build a fusion reactor called the International Thermonuclear Experimental Reactor (ITER) in Cadarache, France, to demonstrate the feasibility of using sustained fusion reactions for making electricity.

Renewable Energy SourcesRenewable Energy Sources• Energy OptionsEnergy Options:

– We use many different energy sources to do work for us. Energy sources are classified into two groups—nonrenewable and renewable. In the United States, most of our energy comes from nonrenewable energy sources. Coal, petroleum, natural gas, propane, and uranium are nonrenewable energy sources. They are used to make electricity, to heat our homes, to move our cars, and to manufacture all kinds of products.

– These energy sources are called nonrenewable because their supplies are limited. Petroleum, for example, was formed millions of years ago from the remains of ancient sea plants and animals. We cannot make more petroleum in a short time.

– Renewable energy sources include biomass, geothermal energy, hydropower, solar energy, and wind energy. They are called renewable energy sources because they are replenished in a short time. Day after day the sun shines, the wind blows, and the rivers flow. We use renewable energy sources mainly to make electricity.

• Energy from the SunEnergy from the Sun– The sun has produced energy for billions of years.

Solar energy is the sun’s rays (solar radiation) that reach the Earth. This energy can be converted into other forms of energy, such as heat and electricity.

– Solar Energy Can Be Used for Heat• Heat water — for use in homes, buildings, or swimming

pools• Heat spaces — inside homes, greenhouses, and other

buildings• Heat fluids — to high temperatures to operate a turbine to

generate electricity

– Solar Energy Can Be Used for Electricity• Photovoltaic (PV devices) or “solar cells”• Solar Thermal/Electric Power Plants

– The main benefits of solar energy are:• Solar energy systems do not produce air pollutants or

carbon-dioxide• When located on buildings, they have minimal impact on the

environment

– Two limitations of solar energy are: • The amount of sunlight that arrives at the Earth's surface is

not constant. It varies depending on location, time of day, time of year, and weather conditions.

• Because the sun doesn't deliver that much energy to any one place at any one time, a large surface area is required to collect the energy at a useful rate.

• Energy from Water:Energy from Water:– Hydroelectric Power Generator

fish ladders enable fish to migrate upstream past dams.

• Energy from the Tides:Energy from the Tides:– The tide moves a huge amount of water twice each day, and harnessing it

could provide a great deal of energy.

• Harnessing the Wind:Harnessing the Wind:– Wind energy is the fastest growing source of electricity in the world.

In 2008, more than 27,000 megawatts (MW) of new capacity were installed worldwide. This stands as a 36 percent increase in annual additions compared with 2007.

• Energy from Inside Earth:Energy from Inside Earth:– How it works:

• Hot rocks underground heat water to produce steam. • We drill holes down to the hot region, steam comes up, is purified and used to

drive turbines, which drive electric generators. • There may be natural "groundwater" in the hot rocks anyway, or we may need

to drill more holes and pump water down to them.

• The first geothermal power station was built at Landrello, in Italy, and the second was at Wairekei in New Zealand. Others are in Iceland, Japan, the Philippines and the United States.

• In Iceland, geothermal heat is used to heat houses as well as for generating electricity.

• If the rocks aren't hot enough to produce steam we can sometimes still use the energy - the Civic Centre in Southampton, England, is partly heated this way as part of a district heating scheme with thousands of customers..

• Alternative Fuels:Alternative Fuels:– "Alternative fuels" are vehicle fuels that aren't made from petroleum.

There are many kinds of fuels that vehicles can run on that aren't made from petroleum. The United States Department of Energy officially recognizes this list of alternative fuels:• Alcohols - ethanol and methanol. • Compressed natural gas (CNG) - natural gas under high pressure. • Electricity - stored in batteries. • Hydrogen - a very special type of gas. • Liquefied natural gas (LNG) - natural gas that is very, very cold. • Liquefied petroleum gas (LPG) (also called propane) - hydrocarbon gases

under low pressure. • Liquids made from coal - gasoline and diesel fuel that doesn't come from

petroleum. • Biodiesel - a lot like diesel fuel, but made from plant oil or animal fat.

Natural Gas Vehicle

GM HydroGen3 with a microwave-oven-sized fuel-

cell stack.

Hybrid Car

Electric Vehicle