Matter, Energy and ResourcesChapter 16

History of Energy Use• Ancient Greece

and Rome (500 BC) – They used charcoal burning heaters – wood was primary energy source.

• Fuel shortages became a problem because many forests in Greece ran out of wood.•To solve problem, Greeks changed the way they built their homes to utilize solar energy.

United States• Wood use

peaked in the 1880’s

• Coal was then heavily used until the 1920’s (it is still, unfortunately, widely used today).

• After the 1920’s, oil and gasoline became the fuels of choice.

• Advantages: resulted in improvements in sanitation, medicine, and agriculture and a higher standard of living

Oil drilling in Alaska

Oil Drilling, 1906. Palisade Public Library Collection, Loyd Files Research Library, Museum of Western Colorado, 1979

Fossil Fuels

• Disadvantages: cause serious environmental damage, there is an insufficient supply, and they are nonrenewable

Understanding Energy

• Energy is the ability to do work. Work is the product of force x distance.

• First Law of Thermodynamics: Energy is not created or destroyed, it only changes form (energy is conserved).

• Second Law of Thermodynamics: Energy always tends to go from a more usable form (higher quality) to a less usable form (lower quality).

Energy Efficiency

• First Law Efficiency: calculated as the ratio of actual amount of energy delivered where it is needed to the amount of energy supplied to meet that need.

actual energy/supplied energy x 100

• If a furnace burns 1.5 units of energy from fuel, but only delivers one unit of energy:

1 unit1.5 units = 67% efficiency

• What happens to the other 33%?

Energy Efficiency

• Second law efficiencies are usually lower than first law and can be improved by developing better technology.

• One of the ways that this can be achieved is by matching energy quality with its end use – don’t use a blow torch to light a candle!

• Heat engines produce work from heat, like electricity generating power plants, human bodies, and internal combustion engines of cars. Many have adverse environmental effects – acid rain, urban smog, thermal pollution, and global warming.

How does energy get from a power plant to your home?

• Created in large power plant •The energy created in the power plant is fed into a grid, like power lines•The electricity then arrives at homes, shops, farms, factories, schools, government buildings, and other places. There it creates heat, light, drives motors and other machinery.

San Onofre Nuclear Generating Station (SONGS) in San Onofre, California. It is 75% owned by So Cal Edison, which is the company that supplies electricity to the inland empire. Today, SONGS provides nearly 20% of the power to more than 15 million people in Southern California -- enough power to serve 2.75 million households

A geothermal plant in Iceland

Renewable and Nonrenewable Energy Sources

The world’s largest solar plant in Germany

• Petroleum, coal, and natural gas produce 90% of energy in the U.S. They are fossil fuels and are not renewable.

•Renewable energy sources include geothermal, nuclear, hydropower, solar energy, and wind power. As fossil fuels are consumed, there will have to be a shift to a greater use of renewables. A bill recently passed in the House of Representatives that will require utility companies to derive 15% of their energy from renewables by 2020. Currently, only 6% comes from renewables.

Energy Consumption•The United States has only 5% of the world’s population, uses 25% of the energy worldwide. •Energy consumption in the U.S. has increased dramatically. From the 1950’s to the 1970’s it more than doubled from 30 exajoules to 70 exajoules. Since the ’80’s the increase has slowed down, though. Why do you think this is?

How to increase energy efficiency:•Get by with less energy use (how could this be accomplished?•Designing equipment to yield more output•Cogeneration: capturing waste heat and using itWhere is energy used?Space heating, cooling of homes and offices, water heating, and industrial processes account for about 60% of energy use. Mass transit (bus, train, airplane, subway) only account for about 5%

Energy Conservation• Building and design • Construct new homes that minimize

energy consumption• Position homes to utilize solar energy• In old homes use insulation, caulking,

weatherstripping, etc.• Problems include indoor air pollution and

prohibitive costsKelley Engineering Center is certified LEED Gold from U.S. Green Building Council, making it the “greenest” academic engineering building in United States. The four-story, 153,000-sq.ft., $45 million building features extensive sustainable "green" design elements, used to educate students and others about sustainability and renewable energy issues. Located at OSU.

Energy Conservation

• Automobile design• Development of

more fuel efficient cars

• Hybrid vehicles• Electric cars• Vehicles that use natural gas• Vehicles that use biofuels• Problems: Tend to be smaller and not as safe

and can be expensive.

The Toyota Prius

• Values and Choices• Commute less distance to work• Use public transportation• Purchase smaller or hybrid cars• Ride bike or walk to work• Turn off lights and appliances when not in use.• Use less air conditioning• Use lower wattage light bulbs

Energy Conservation

The BART metro system in San Francisco

U.S. Energy Policy

• Has not moved us closer to self – sufficiency and less reliance on foreign sources of fossil fuels.

• Oil is imported more now than ever

• U.S. needs to focus more on research and development for alternative energy sources than it has in the past.

Hard Path Energy Policies

• Finding more fossil fuels and creating more energy plants

• Continue with the same energy use• Comfortable, requires no new thinking and no

change in political, social, or economic conditions

• Need to exploit coal, natural gas, petroleum and find ways to reduce their environmental effects

• George Bush’s 2001 plan is hard path. It calls for the construction of 1000 new fossil fuel plants in the next 20 years.

Soft Path Energy Policies

• Emphasis on energy quality, renewable energy, and flexible energy

• More environmentally friendly

• Aimed at increasing 2nd law efficiencies and increasing energy quality

• Decrease wasted energy

• Advocated by a man named Amory Lovins

Current Patterns in Energy Use

• Eastern and Southeastern U.S. the fuel of choice is coal (the dirtiest fossil fuel).

• West Coast – power plants burn oil and natural gas (the cleanest burning fossil fuel) or use hydropower from dams to produce electricity.

• Places where many people commute use a large portion of energy in transportation.

Two choices for the future

• Continue with our dependence on fossil fuels and face the consequences that will result in the future.

• Shift away from our reliance on nonrenewable fuels and begin building a sustainable energy future.

Units of energy and power - Conversions

Energy:• 1 calorie (cal) = 4.18 joules (J)• 1000 calories = 1 Calorie (kilocalorie)• 1Btu = 252 calories or 1053.36 joules• 1 kWh = 3412 Btu (kWh is used mostly for

electricity)• 1 kWh = 3.6 x 106 J Power: • 1 watt = 1 joule/second• 1 kW = 1000 joules/second