Part 2 Alternate Energy Sources

Earth’s Resources : 

Earth’s Resources Alternate Energy Sources

Chapter 4.2 : 

Chapter 4.2 Objectives Evaluate the advantages of solar energy Explain how nuclear power plants use nuclear fission to produce energy Evaluate wind power’s potential for providing energy in the future Relate how hydroelectric power, geothermal energy, and tidal power contribute to our energy resources

Alternate Energy Sources : 

Alternate Energy Sources We live in an age of fossil fuels, but as we use the fossil fuels they deplete and one day there will not be enough left to provide our energy needs Today these resources supply 90% of our energy needs At our current usage rate these resources will be gone in 170 years

Alternate Energy Sources : 

Alternate Energy Sources But, the “current rate” changes every day. It INCREASES! Some reasons are: Increasing population New industrialization of countries which need more resources So, we need alternatives

Alternative Energy Sources : 

Alternative Energy Sources Some possible alternatives are: Solar Energy Nuclear Energy Wind Energy Hydroelectric Power Geothermal Energy Tidal Power

Solar Energy : 

Solar Energy Solar Energy is the use of the sun’s rays to supply heat or electricity There are two advantage to using Solar Energy: The “fuel” is free It is non polluting

Solar Energy : 

Solar Energy The simplest and perhaps most common solar energy systems now in use are passive solar collectors Example: South facing windows in a home As sunlight passes through the glass, objects in the room absorb its heat. These objects radiate the heat, which warms the air Example: Putting the water hose on the roof This warms the water in the hose which helps the house water heater not have to work as much or as hard

Solar Power : 

Solar Power More elaborate systems such as active solar collectors These can be mounted on the roofs of buildings They are usually blackened boxes covered with glass or plastic The heat they collect can be transferred to areas where it is needed by circulating air or liquids through piping In one country, solar collectors provide hot water for more than 80% of the homes!

Solar Power : 

Solar Power Another type of collector uses photovoltaic cells to convert the sun’s energy into electricity We can see these mounted on homes, near buildings, on poles, and even in our calculators which do not use sunlight, but whatever light is available, such as that of lightbulbs in a house

Solar Energy : 

Solar Energy This is an example of a car (used to travel across several states in a competition between colleges) that uses the suns energy to create the electricity needed to power the car

Solar Power : 

Solar Power Solar Powered flight This is the Pathfinder Plus/Helios The Pathfinder-Plus solar powered aircraft set a new altitude record of 80,201 feet in 1998. Another unique solar-powered flying wing called Helios soared to 96,863 feet in 2001.

Solar Power : 

Solar Power The sun21 It crossed the Atlantic ocean from Seville, Spain to New York City using only solar power It took about seven months

Solar Power : 

Solar Power Solar power can be used in building to heat water and create electricity

Solar Energy : 

Solar Energy Drawbacks to solar energy: Necessary equipment and installation is still expensive Solar energy is not enough. Even when using it, other sources have to be available when the sun is not there to provide energy, such as during cloudy conditions, low light conditions such as winter, or at night

Nuclear Energy : 

Nuclear Energy Currently nuclear power meets about 7% of the USA energy demands The fuel comes from radioactive materials that release energy through nuclear fission In nuclear fission, the nuclei of heavy atoms such as uranium-235 are bombarded with neutrons. The uranium nuclei then split into smaller nuclei and emit neutrons and heat energy The new neutrons released do the same thing to other atoms around them producing a chain reaction

Nuclear Energy : 

Nuclear Energy That was the good news! But, if we are not careful and control the process then the process can spin out of control. The result?????

Nuclear Energy : 

Nuclear Energy However, we do keep the reactions controlled by using neutron absorbing rods These rods are moved into or out of the reactor as needed The result is a controlled nuclear chain reaction that releases great amounts of heat The energy drives turbines that turn electrical generators, thus making electricity

Nuclear Energy : 

Nuclear Energy At one time people thought nuclear energy would solve our energy problems, but it didn’t happen. Cost for nuclear facilities is very expensive Nuclear facilities produce nuclear waste which must be disposed of Concern over nuclear accidents such as 3-mile Island and Chernobyl that release radiation into the air

Nuclear Power : 

Nuclear Power Diablo Canyon Nuclear Power Plant near San Lous Obisbo, California Reactors are the dome shaped buildings You can see cooling water being released into the ocean

Wind Energy : 

Wind Energy How big of an impact could wind energy have on meeting our energy needs? According to one estimate, if just the winds of North and South Dakota could be harnessed, they would provide 80% of the electrical energy used in the USA

Wind Energy : 

Wind Energy Using the wind for energy is not a new idea For centuries people used wind to power sailing ships Many cultures used windmills to grind grain Others used wind for separating grain from its husk

Wind Energy : 

Wind Energy The “energy crisis” brought about by the Arab oil embargo of the 1970s caused an interest in alternative energy possibilities, including wind energy So, the government started a program in the 1980s to study the use of wind to provide energy This resulted in the growth of “wind farms

Wind Energy : 

Wind Energy Some experts estimate that in the next 50 -60 years, wind power could meet 5%-10% of the country’s demand for electricity There are a few problems to overcome first Technology needs to increase Noise pollution must be reduced Cost of land is high

Hydroelectric Power : 

Hydroelectric Power Like wind, moving water has been used for centuries Waterwheels powered mills and machinery Today, falling water generates hydroelectric power The water drives the turbines that generate the electricity The water held behind a dam is a form of “stored energy” that can be released through the dam to produce electric power

Hydroelectric Power : 

Hydroelectric Power Although water power is a renewable resource, the dams that house the equipment making the electricity have limited useful lifetimes Sediments get deposited behind the dams Sediments fill the reservoir 50-300 years to fill up

Hydroelectric Power : 

Hydroelectric Power Limiting factors Suitable building sites are an important limiting factor Dams can’t be built just anywhere Most of the good sites in the US have already been developed. This limits future expansion To be good the site must have Significant height for water to fall A high rate of water flow

Geothermal Energy : 

Geothermal Energy Geothermal energy is harnessed by tapping natural underground reservoirs of steam and hot water The hot water is used directly for heating and to turn turbines to generate electric power The reservoirs can be found where subsurface temperatures are high due to recent volcanic activity

Geothermal Energy : 

Geothermal Energy In the US, areas in several western states use hot water from geothermal sources for heat. The first commercial plant in the US was built in 1960 at “The Geysers” The Geysers is an important source of electrical power for San Francisco and Oakland Nevada, Utah, and Imperial Valley (CA) are also developing geothermal power systems

Geothermal Energy : 

Geothermal Energy The Geysers Is the world’s largest electricity generating geothermal facility Most of the steam wells are about 3,000 meters deep

Geothermal Energy : 

Geothermal Energy Geothermal energy is clean, but not inexhaustible When hot water is pumped out, some reservoirs cannot replace that water Individual wells usually last only 10-15 years, so new wells must be drilled Eventually the field is depleted

Tidal Power : 

Tidal Power The development of tidal power is an example of energy production from the ocean For hundreds of years tides have been a power source In the 1100s, tides drove water wheels that powered gristmills and sawmills In the 1600s and 1700s a tidal mill produced much of Boston’s flour

Tidal Power : 

Tidal Power How does tidal power work? Tidal power is harnessed by constructing a dam across the mouth of a bay or an estuary in coastal areas with a large tidal range The strong in and out flow that results drives turbines and electric generators The largest tidal power plant ever constructed is at the mouth of France’s Rance River Started operation in 1966

Tidal Power : 

Tidal Power Tidal power development isn’t economical if the tidal range is less than 8 meters or if a narrow, enclosed bay is not available