Nonrenewable Energy Resources Quiz

Module 34: Patterns of Energy Use

• Nonrenewable energy is used worldwide and in the United States

• Fossil fuel: A fuel derived from biological material that became fossilized millions of years ago

• Nonrenewable energy resource: An energy source with a finite supply, primarily fossil fuels and nuclear fuels

• Nuclear fuel: Fuel derived from radioactive materials that give off energy

• Worldwide annual energy consumption (2011) was dominated by oil, coal, and natural gas. Fossil fuels accounted for 82%, Oil-32%, Natural gas-21%, Coal/peat- 29%, and renewable energy 13%. Nuclear fuel accounted for 5%.

Units of Energy and Power

• Energy is the ability to do work or transfer heat. Units include joule (J), British Thermal Unit (BTU), calorie, and kilowatt-hour (kWh).
• Power is the rate at which work is done. Units include watt (W) and horsepower (hp). 1 horsepower equals 745.7 watts.
• A calorie is a basic unit of energy. 1 kilocalorie (kcal) = 1,000 calories = 4,184 joules

Math Conversion

• 600 Calories (kcal) is equal to 2,510,400 joules.
• 5 horsepower equals 3,730 watts.

Worldwide Patterns of Energy Use

• A bar graph shows total annual energy consumption (in exajoules) for various countries, and a related bar graph shows per capita annual energy consumption (in gigajoules) for the mentioned countries.
• The 10 featured countries list represent a spread of both high and low energy consumption figures.

Global Energy Consumption Flowchart

• The graphic identifies various types of energy use (past, present, future) with the main components: energy, human consumption, energy return on investment, externalities. Associated categories include: Food Animal Coal Gas Sustainable Wood Wind Oil

Worldwide Patterns of Energy Use

• Commercial energy source: An energy source that is bought and sold.
• Subsistence energy source: An energy source gathered by individuals for their own immediate needs.

Worldwide Patterns of Energy Use: USA

• From 1850 to 2012, energy consumption increased significantly for every source (wood, coal, oil, renewables, hydroelectric power, and natural gas). Wood began declining in the 20th century, eventually overtaken by fossil fuels, which accounted for the majority of US energy sources, with natural gas having the most significant recent increase.

Pie Chart of Total US Energy Consumption in 2012

• Fossil fuels made up almost all energy consumption at 95 quadrillion BTUs. Oil accounted for 37%, Coal accounted for 18%, and Natural Gas accounted for 27%.
• Renewables accounted for 8% of energy consumption, with nuclear fuel being 10%.

Review the Law!

• The Second Law of Thermodynamics dictates that when energy is transformed, its ability to do work diminishes because some energy is lost during each conversion.

Quantifying Energy Efficiency

• Energy efficiency refers to the effectiveness of the processes used to obtain fuel and convert it into work. Coal provides a prime example. Energy is lost throughout extraction, processing, transport, and disposal.

Different energy forms are best suited for specific purposes.

• The ideal energy source depends on the specific need. Energy return on energy invested (EROI) is a measure of effectiveness. EROI = (Energy obtained from fuel)/(Energy invested to obtain fuel). The higher the EROI value, the more efficient the energy.
• Example: Data show different EROI values for coal extracted via surface mining versus subsurface mining, and for hydroelectric power compared to ethanol.

Efficiency and Transportation

• Nearly 30% of US energy is used for transportation. Efficiency is crucial in this sector.
• Transportation relies primarily on vehicles powered by petroleum products (e.g., gasoline and diesel).
• Data (graph) show a trend in overall US vehicle fuel efficiency, with some fluctuation over time.

Electricity Accounts for 40% of Our Energy Use

• Electricity is a common energy carrier.
• Significant energy conversion losses occur during electricity generation, such that only 13% of the total energy consumed is available for final use.

The Process of Electricity Generation

• All thermal power plants convert fuel's potential energy into electricity.
• Turbine: A device with blades (water, wind, steam, or exhaust) that turns a generator.
• Electrical grid: A network of interconnected transmission lines connecting plants and consumers.

The Process of Electricity Generation (Steps using Coal)

• Coal's energy transforms water into steam.
• Steam's kinetic energy rotates a turbine.
• The turbine's rotation powers a generator to produce electricity.

Efficiency of Electricity Generation

• Combined cycle: A power plant that utilizes both exhaust gases and steam turbines.
• Capacity: Maximum electrical output of a plant.
• Capacity factor: The operating time of a power plant per year.
• Cogeneration: The simultaneous generation of both heat and electricity using a single fuel source; this improves the efficiency of electricity generation to as high as 90 percent.

Module 35: Fossil Fuel Resources

• This module discusses the uses and consequences of coal, petroleum, natural gas, oil sands, and liquefied coal. It also forecasts the future use of fossil fuels.

Coal

• Coal is the most abundant and dirtiest fossil fuel. Coal is a solid fuel coming from millions of years of compressed plant matter.
• Types of coal include lignite, sub-bituminous, bituminous, and anthracite.
• Coal formation: Peat, Lignite, Bituminous, and Anthracite coal are formed over millions of years beneath layers of rock and sediment.

Coal: Advantages

• Energy-dense
• Plentiful
• Easy to exploit by surface mining
• Relatively Inexpensive
• Easy to handle and transport
• Needs little refining

Coal: Disadvantages

• Contains impurities
• Releases impurities into the air when burned
• Combustion leads to increased air pollutants
• Ash left behind can contribute to runoff

Petroleum

• Petroleum: A fossil fuel occurring in underground deposits as a liquid mixture of hydrocarbons, water and sulfur. Raw petroleum products taken from the ground are called crude oil.

Petroleum: Advantages

• Convenient to transport and use
• Relatively energy dense
• Cleaner burning than coal
• Used in many applications

Petroleum: Disadvantages

• Releases carbon dioxide into atmosphere
• Possibility of leaks during extraction/transport
• Run-off into marine waterways
• Releases sulfur, mercury, lead, and arsenic into the atmosphere when burned
• Potential for environmental damage near drilling sites (ANWR debate)

Natural Gas

• Natural gas, a component of petroleum, exists as gaseous deposits separate from petroleum.
• Composition: Mostly methane with some ethane, propane, and butane.

Natural Gas: Advantages

• Contains fewer impurities, emitting almost no sulfur dioxide or particulates.
• Emits only 60 percent as much carbon dioxide as coal.

Natural Gas: Disadvantages

• Methane leakage into the atmosphere is a potent greenhouse gas.
• Natural gas exploration can contaminate groundwater.

Oil Sands and Liquefied Coal

• Oil sands are slow-flowing, viscous deposits of bitumen mixed with sand, water and clay.
• Bitumen is degraded petroleum that forms when petroleum surfaces and is shaped by bacteria.

Fossil Fuels are Finite Resource

• Energy Intensity: The energy use per unit of gross domestic product.
• US per capita energy use has been declining recently, despite population growth.

The Hubbert Curve

• A graphical representation of the total petroleum production over time.
• The graph's shape, whether showing an upper or lower estimate of total reserves, indicates that the date by which peak depletion will occur is not strongly affected—i.e., is not substantially different.

The Future of Fossil Use

• If current use continues without additional discovery, conventional oil may be exhausted within 50 years.
• Coal supplies are expected to last at least two centuries.
• New technologies and concerns about greenhouse gasses encourage exploration into alternative energy sources.

Module 36: Nuclear Energy Resources

• Nuclear energy describes the processes of using nuclear fuels to generate electricity. It highlights advantages and disadvantages.

Nuclear Reactors Use Fission to Generate Electricity

• Uranium-235: Used as a fuel source in nuclear electricity generation.
• Fission: A nuclear reaction where a neutron strikes a relatively large atomic nucleus, and the nucleus splits into more parts, releasing additional neutrons and energy (heat).
• Nuclear power plants use nuclear fission heat to boil water, producing steam that turns a turbine and drives a generator.

Nuclear Fission

• The process in which neutrons split larger atomic nuclei into smaller ones, releasing energy. This energy is then used to make steam, turn turbines.

Nuclear Reactors Use Fission to Generate Electricity

• Fuel rod: A cylindrical tube containing nuclear fuel in a nuclear reactor.
• Control rod: A cylindrical device placed between fuel rods in a nuclear reactor to absorb excess neutrons, slowing or stopping the fission reaction.

Nuclear Energy: Advantages and Disadvantages

• Advantages: No air pollution, reduces reliance on imported oil.
• Disadvantages: Possibility of accidents, problematic waste disposal, concern about misuse of nuclear materials.

Radioactive Waste

• Radioactive waste: Nuclear fuel that cannot produce enough heat for a power plant, but continues to emit radioactivity; has very long half-lives.
• Becquerel (Bq): A unit that measures the rate of radioactive material decay. 1 Bq = 1 decay/second.
• Curie: A unit of radiation measure. 1 curie = 37 billion decays/sec

Module 39: Solar, Wind, Geothermal, and Hydrogen

• This module discusses solar, wind, geothermal, and hydrogen energy.

Solar Energy

• Energy from the sun can be captured directly, useful for electricity generation, and many areas with high solar output could support substantial solar energy generation.

Active Solar Energy

• Technologies directly harnessing sunlight. Options include solar water heating systems, photovoltaic systems, and large-scale concentrating solar thermal systems.

Wind Energy

• Wind energy is the kinetic energy of moving air.
• Various countries are establishing significant wind energy capacity.
• Components of wind energy system: Turbine (blade, gearbox) and generator.

Wind Energy: Advantages

• Nondepletable/free (renewable) energy.
• After manufacturing and installation, little input other than wind is required.
• Wind-generated electricity does not pollute or release greenhouse gases.

Wind Energy: Disadvantages

• Most off-grid residential wind energy systems require batteries to store energy.
• Wind turbines can be noisy and visually unappealing.
• Wildlife, including birds and bats, have been shown to be killed by turbine blades.

Geothermal

• Geothermal energy taps the internal heat of the Earth.
• Heat from the Earth can be used directly, or it can generate steam to drive turbines to produce electricity.
• Geothermal resources include ground source heat pumps.

Fuel Cells

• Fuel cells convert fuels (e.g., hydrogen) into electrical current, and water is the only byproduct in most cases.
• Electrolysis is the application of electrical current to water molecules to split them into hydrogen and oxygen molecules.

Module 40: Planning Our Energy Future

• This module forecasts the future of energy usage. It analyzes the economic and environmental implications of using or not using renewable energy to generate electricity.

Our Energy Future

• Efficiency, conservation, and developing sustainable energy strategies are critical for the future.
• One strategy is adopting a smart grid—an electricity transmission network that continuously adjusts energy distribution in response to usage needs.