ENERGY RESOURCES AND FOSSIL FUELSEnvironmental Science

Chapter 17 Section 1

Fossil Fuels• The remains of ancient organisms that changed into coal,

oil, or natural gas.

• Fuels we use to run cars, ships, planes, and factories and to produce electricity.

• Natural resources.

• Two main problems:• Supply is limited.• Obtaining and using them causes environmental problems.

Fuels for Different Uses• Fuels are used for five main purposes:

• Cooking• Transportation• Manufacturing• Heating and cooling buildings• Generating electricity to run machines and appliances

• Sustainability depends on the fuel’s energy content, cost, availability, and safety, and the byproducts of the fuel’s use.

Fuels for Different Uses• Examples:

• Coal• Readily available and inexpensive• Used to heat homes

• Airplane fuel• More energy per mass than coal• Expensive

• Wood• Low energy per mass comparatively• Generally inexpensive

Electricity – Power on Demand• Energy in fuels is often converted into electrical energy in

order to power machines.

• Can be transported quickly across great distances.

• Generated in power plants.

• Disadvantages:• Difficult to store.• Other energy sources have to be used to generate it.

Electricity – Power on Demand• How is Electricity Generated?

• Electric generator – machine that converts mechanical energy into electrical energy.

• Turbine – a wheel that changes the force of a moving gas or liquid into energy that can do work.

• Most power plants boil water to produce steam that turns the turbine.

• Turbine spins a generator to produce electricity.

Electricity – Power on Demand

Energy Use• World Patterns

• People in developed societies use much more energy that people in developing countries.

• Energy use in some developing countries is growing rapidly.

Energy Use• Energy Use in the United States

• The United States uses more energy per person than any other country in the world except for Canada and the United Arab Emirates.

• More than 25% is used to transport goods and people. Other countries have better mass transportation systems.

• Fuel is lower cost in the U.S. than other places, which leads to greater usage.

How Fossil-Fuel Deposits Form• Coal Formation

• Coal forms from the remains of plants that lived in swamps hundreds of millions of years ago.

• Layers of sediment added as the sea level rose and fell and compressed the remains, causing coal to form.

How Fossil-Fuel Deposits Form• Oil and Natural Gas Formation

• Result from the decay of tiny marine organisms that accumulated on the bottom of the ocean millions of years ago.

• Buried by sediments, then heated until they became complex energy-rich carbon-based molecules.

• Over time, molecules migrated into the porous rocks that now contain them.

• Much is found in Alaska, Texas, California, and the Gulf of Mexico.

How Fossil-Fuel Deposits Form

Coal• Coal Mining and the Environment

• Environmental effects of mining coal vary.• Underground mines can have a minimal effect on the surface.• Sometimes, it is necessary to disturb the surface of the land to

reach the deposit.• Toxic chemicals can leach into nearby streams.

Coal• Air Pollution

• Bituminous coal (high-grade) produces more heat and less pollution than lignite (low-grade).

• Sulfur is a major source of coal pollution.• Results in acid rain.

Petroleum• Petroleum – oil that is pumped from the ground – crude

oil.

• Petroleum product – anything that is made from crude oil.• Fuels• Chemicals• Plastics

Petroleum• Locating Oil Deposits

• Oil is found in and around major geologic features, such as folds, faults, and salt domes.• Impermeable layers of rock prevent the oil from escaping.

• Most of the world’s oil reserves are in the Middle East.• Large deposits also exist in the U.S., Venezuela, the North Sea,

Siberia, and Nigeria.• Oil is removed from a well and then transported to a refinery to be

converted into fuels and other petroleum products.

Petroleum• The Environmental Effects of Using Oil

• When petroleum fuels are burned, they release pollutants.• Emissions regulations and technology have helped to reduce air

pollutants.• Oil spills are dramatic, but cars leaking oil causes more pollution

every day.

Petroleum• Natural Gas

• About 20% of the world’s nonrenewable energy.• Many oil wells recover natural gas.• Fewer pollutants than other fuels.

Fossil Fuels and the Future• Predicting Oil Production

• Oil production is increasing, but more slowly than in the past.• Oil reserves – oil deposits that can be extracted profitably at

current prices using current technology.• All predictions of future oil production are guided by an important

principle:• The relative cost of obtaining fuels influences the amount of fossil fuels

that we extract from the Earth.• i.e. as supply decreases, we may rely on other sources.

Fossil Fuels and the Future• Future Oil Reserves

• No large oil reserves have been discovered recently.• Deep-ocean may be tapped in the future.• Many issues.• Think of the BP oil spill in the Gulf…