Alternative Energy and Conservation

Chapter 18Section 2

Warm Up

• http://www.youtube.com/watch?v=1-g73ty9v04&feature=related

• Energy Conservation Cartoon Video• http://www.youtube.com/watch?v=q_fvbO2V

Xjc• Alternative source of energy

Learning Objectives

This section describes three forms of alternative energy and discusses energy efficiency and energy conservation

Students will know• To describe three alternative energy technologies• To identify two ways that hydrogen could be used as a fuel

source in the future• To explain the difference between energy efficiency and

energy conservation• To describe two forms of energy efficient transportation.• To list ways by which you can conserve energy in your daily

life

What you Know

• Write down where energy is being wasted in school and in your home and list ways that energy could be saved both at school and in home.

• You may work with your partner.

Internet Activity

• You can make use of internet sources to investigate different types of alternative fuel vehicles and create a sales brochure.

Math Problem on energy saving• The price of gas keeps going up. In California, most gas stations now charge over $4 even for the lowest

octane gasoline. Hybrid cars cost more, but are more energy efficient than most standard gasoline-only cars. Hybrid cars are also better for the environment. Are they better for your wallet as well? figure out the break-even time for a hybrid car, and how much money you could save over the lifetime of a hybrid car given the following

This is a real-life question, one that a car buyer should think about. • A standard new car would cost $20,000 and gets 24 miles per gallon. • The same or similar car with a hybrid engine will cost $27,000 and gets 40 miles per gallon. In other words,

a hybrid would cost $7,000 more. • On average, the car is driven 15,000 miles a year, and will last 10 years• The price for gas is fixed at $4.00 per gallon

• Figure out how much more gas a regular car uses than a hybrid in going 1 mile • Figure out the savings in one year

• Figure out the number of years it will breakeven

• Figure out savings in the lifetime of a car

Key Terms

• Alternate energy• Ocean Thermal Energy conversion (OTEC)• Fuel cell• Energy efficiency• Energy conservation

Alternative Energy

• Alternative energy describes energy sources that are still in development. Some renewable energy sources that we use now, such as geothermal power, were once considered alternative energy.

• For an alternative energy source to become a viable option for the future, the source must be proven to be cost effective. Also the environmental effects of using the energy source must be acceptable.

Tidal power

• Tides are the movement of water in the oceans and seas caused by gravitational attraction between the sun, Earth, and moon. The tides, which happen twice each day, are marked by the rising and falling of the sea level.

• The energy of the tides was used nearly a thousand years ago to power mills in France and Britain. Today tidal power is used to generate electricity in countries such as France, Russia, and Canada.

How a tidal plant works

How a Tidal Plant works?• As the tide rises, water flows behind a dam; when

the sea level falls, the water is trapped behind the dam. When the water in the reservoir is released, it turns a turbine that generates electricity. Although tidal energy is renewable and nonpolluting, it will not become a major source of energy in the future.

• The cost of building and maintaining a tidal power plant is high, and there are few locations that are suitable.

OCEAN THERMAL ENERGY CONVERSION

• In the tropics, the temperature difference between the surface of the ocean, which is warmed by solar energy, and deep ocean waters can be as much as 240C. An experimental power station off the shores of Hawaii uses this temperature difference to generate electricity. This technology is called ocean thermal energy conversion (OTEC).

How Ocean Power Operates

OTEC• In this system, warm surface water is used to boil sea water. This is

possible because water boils at low temperatures when it is at low pressure in a vacuum chamber. The boiling water turns into steam, which spins a turbine. The turbine runs an electric generator. Cold water from the deep ocean cools the steam, turning the steam into water that can be used again.

• Japan has also experimented with OTEC power, but so far, no project has been able to generate electricity cost effectively.

• One problem with OTEC is that the power needed to pump cold water up from the deep ocean uses about one third of the electricity that the plant produces. Therefore, the OTEC plants are inefficient.

• The environmental effects of pumping large amounts of cold water to the surface are also unknown.

HYDROGEN – A FUTURE FUEL SOURCE?

• Hydrogen, the most abundant element in the universe can be burned as a fuel. Hydrogen is found in every molecule of living things, and is also found in water. Hydrogen does not contain carbon, so it does not release pollutants associated with burning fossil fuels and biomass. When hydrogen is burned in the atmosphere, it combines with oxygen to produce water vapor, a harmless byproduct, and small amounts of nitrogen oxides.

• Hydrogen gas can be produced by using electricity to split molecules of water. We may also be able to grow plants to produce hydrogen cost effectively.

• Hydrogen fuel can be made from any material that contains a lot of hydrogen, including the plot of switch grass as shown in the picture below.

Hydrogen Fuel

• Hydrogen fuel can be made from any material that contains a lot of hydrogen, including the experimental plot of switchgrass shown here

THE CHALLENGES OF HYDROGEN FUEL

• One difficulty with hydrogen fuel is that it takes a lot of energy to produce. If this energy comes from burning fossil fuels, generating hydrogen would be expensive and polluting. One alternative is to use electricity from solar cells and wind power to split water molecules to produce hydrogen. Hydrogen could then be stored in pressurized tanks and transported in gas pipelines. Or hydrogen might not be stored at all it might be used as it is produced, in fuel cells.

Fuel Cells

• Fuel cells produce electricity chemically, by combining hydrogen fuel with oxygen from the air. When hydrogen and oxygen are combined electrical energy is produced and water is the only byproduct. Fuel cells can be fueled by anything that contains plenty of hydrogen, including natural gas, alcohol, or even gasoline.

• The space shuttles have used fuel cells for years. By 2010, portable devices such as phones and video-game players may be powered by micro fuel cells. These fuel cells would be fueled with alcohol and may end the problem of charging or changing batteries.

Fuel Cells

ENERGY EFFICIENCY

• There are two main ways to reduce energy use – lifestyle changes and increases in energy efficiency. Lifestyle changes might include walking or biking for short trips and using mass transit.

• Energy efficiency is the percentage of energy put into a system that does useful work. Energy efficiency can be determined using this simple equation :

• Energy efficiency (in%) = energy out/energy in x 100• More than 40% of all commercial energy used in the United States is

wasted. Most of it is lost from inefficient fuel wasting vehicles, furnaces, and appliances and from leaky, poorly insulating buildings.

• We could save enormous amounts of energy by using fuel cells instead of internal combustion engines in cars, and by changing from incandescent to fluorescent light bulbs.

Incandescent vs fluorescent bulbs

EFFICIENT TRANSPORTATION

• Nothing would increase the energy efficiency of American life more than developing efficient engines to power vehicles and increasing the use of public transportation systems. In the United States, gasoline prices are currently so low that there is little demand for fuel-efficient vehicles, which are more common in other countries.

Hybrid Cars

Hybrid Truck

COGNERATION

• The production of two useful forms of energy from the same fuel source is called cogeneration. For example, the waste heat from an industrial furnace can power a steam turbine that produces electricity. The industry may use the electricity or sell it to a utility company. Small cogeneration systems have been used for years to supply heat and electricity to multiple buildings at specific sites.

ENERGY CONSERVATION

• Energy conservation means saving energy, it can occur in many ways, including using energy efficient devices and wasting less energy.

• Bicycling instead of driving is one of saving energy.

Hybrid cars• Hybrid cars, such as the one shown above are examples of energy-

efficient vehicles currently in use.• Hybrid cars use a small, efficient gasoline engine most of the time,

but they also use an electric motor when extra power is needed, such as while accelerating.

• They convert some of the energy of braking into electricity and they store this energy in the battery.

• To save fuel, hybrid cars sometimes shut off the gasoline engine, such as when the car is stopped at a red light.

• Hybrid cars are also designed to be aerodynamic, and they are made of lightweight materials so that they need less energy to accelerate.

• Hybrid cars do not cost much more than conventional vehicles, they cost less to refuel, and they produce less harmful emissions.

• Cities and towns saving energy: the towns of Osage, Iowa, numbers 3,600 people. The town adopted an energy conservation plan that saves more than $1million dollars. The residents plugged the leaks around the windows and doors where much of the heat escapes from a house. They replaced inefficient furnaces and insulated their hot water heaters.

Town of Osage

Conservation Tips

• Conservation around the home: most of the energy lost from homes is through poorly insulated windows, doors, walls, and the roof. So a good way to increase energy efficiency is to add to the insulation of a home.

• Replacing the old windows with new high efficiency windows can reduce energy bill by 15%

• Whenever you save energy, you not only save money, you also reduce the demand for such fossil fuels as coal, oil, and natural gas. Less burning of fossil fuels also means lower emissions of carbon dioxide (CO2), the primary contributor to global warming, and other pollutants.

Home Appliances• Turn your refrigerator down. Refrigerators account for about 20% of Household electricity use. Use a

thermometer to set your refrigerator temperature as close to 37 degrees and your freezer as close to 3 degrees as possible. Make sure that its energy saver switch is turned on. Also, check the gaskets around your refrigerator/freezer doors to make sure they are clean and sealed tightly.

• Set your clothes washer to the warm or cold water setting, not hot. Switching from hot to warm for two loads per week can save nearly 500 pounds of CO2 per year if you have an electric water heater, or 150 pounds for a gas heater.

• Make sure your dishwasher is full when you run it and use the energy saving setting, if available, to allow the dishes to air dry. You can also turn off the drying cycle manually. Not using heat in the drying cycle can save 20 percent of your dishwasher's total electricity use.

• Turn down your water heater thermostat. Thermostats are often set to 140 degrees F when 120 is usually fine. Each 10 degree reduction saves 600 pounds of CO2 per year for an electric water heater, or 440 pounds for a gas heater. If every household turned its water heater thermostat down 20 degrees, we could prevent more than 45 million tons of annual CO2 emissions - the same amount emitted by the entire nations of Kuwait or Libya.

• Select the most energy-efficient models when you replace your old appliances. Look for the Energy Star Label - your assurance that the product saves energy and prevents pollution. Buy the product that is sized to your typical needs - not the biggest one available. Front loading washing machines will usually cut hot water use by 60 to 70% compared to typical machines. Replacing a typical 1973 refrigerator with a new energy-efficient model, saves 1.4 tons of CO2 per year. Investing in a solar water heater can save 4.9 tons of CO2 annually.

Home Heating and Cooling

• Be careful not to overheat or overcool rooms. In the winter, set your thermostat at 68 degrees in daytime, and 55 degrees at night. In the summer, keep it at 78. Lowering your thermostat just two degrees during winter saves 6 percent of heating-related CO2 emissions. That's a reduction of 420 pounds of CO2 per year for a typical home.

• Clean or replace air filters as recommended. Energy is lost when air conditioners and hot-air furnaces have to work harder to draw air through dirty filters. Cleaning a dirty air conditioner filter can save 5 percent of the energy used. That could save 175 pounds of CO2 per year.

Small investments that pay off• Buy energy-efficient compact fluorescent bulbs for your most-used lights.

Although they cost more initially, they save money in the long run by using only 1/4 the energy of an ordinary incandescent bulb and lasting 8-12 times longer. They provide an equivalent amount of bright, attractive light. Only 10% of the energy consumed by a normal light bulb generates light. The rest just makes the bulb hot. If every American household replaced one of its standard light bulbs with an energy efficient compact fluorescent bulb, we would save the same amount of energy as a large nuclear power plant produces in one year. In a typical home, one compact fluorescent bulb can save 260 pounds of CO2 per year.

• Wrap your water heater in an insulating jacket, which costs just $10 to $20. It can save 1100 lbs. of CO2 per year for an electric water heater, or 220 pounds for a gas heater.

• Use less hot water by installing low-flow shower heads. They cost just $10 to $20 each, deliver an invigorating shower, and save 300 pounds of CO2 per year for electrically heated water, or 80 pounds for gas-heated water.

Getting around

• Whenever possible, walk, bike, car pool, or use mass transit. Every gallon of gasoline you save avoids 22 pounds of CO2 emissions. If your car gets 25 miles per gallon, for example, and you reduce your annual driving from 12,000 to 10,000 miles, you'll save 1800 pounds of CO2.

• When you next buy a car, choose one that gets good mileage. If your new car gets 40 miles per gallon instead of 25, and you drive 10,000 miles per year, you'll reduce your annual CO2 emissions by 3,300 pounds.

Reduce, reuse, recycle

• Reduce the amount of waste you produce by buying minimally packaged goods, choosing reusable products over disposable ones, and recycling. For every pound of waste you eliminate or recycle, you save energy and reduce emissions of CO2 by at least 1 pound. Cutting down your garbage by half of one large trash bag per week saves at least 1100 pounds of CO2 per year. Making products with recycled materials, instead of from scratch with raw materials, uses 30 to 55% less for paper products, 33% less for glass, and a whopping 90% less for aluminum.

• If your car has an air conditioner, make sure its coolant is recovered and recycled whenever you have it serviced. In the United States, leakage from auto air conditioners is the largest single source of emissions of chlorofluorocarbons (CFCs), which damage the ozone layer as well as add to global warming. The CFCs from one auto air conditioner can add the equivalent of 4800 pounds of CO2 emissions per year.

Home Improvements

When you plan major home improvements, consider some of these energy saving investments. They save money in the long run, and their CO2 savings can often be measured in tons per year.

• Insulate your walls and ceilings. This can save 20 to 30 percent of home heating bills and reduce CO2 emissions by 140 to 2100 pounds per year. If you live in a colder climate, consider superinsulating. That can save 5.5 tons of CO2 per year for gas-heated homes, 8.8 tons per year for oil heat, or 23 tons per year for electric heat. (If you have electric heat, you might also consider switching to more efficient gas or oil.)

• Modernize your windows. Replacing all your ordinary windows with argon filled, double-glazed windows saves 2.4 tons of CO2 per year for homes with gas heat, 3.9 tons of oil heat, and 9.8 tons for electric heat.

• Plant shade trees and paint your house a light color if you live in a warm climate, or a dark color if you live in a cold climate. Reductions in energy use resulting from shade trees and appropriate painting can save up to 2.4 tons of CO2 emissions per year. (Each tree also directly absorbs about 25 pounds of CO2 from the air annually.)

CONSERVATION IN DAILY LIFE

• There are simple lifestyle changes that can help save energy. Using less of any resource usually translates into saving energy.

• http://www.energyquest.ca.gov/saving_energy/index.html