APES Unit 6

Solar energy

Energy from the Sun captured for heating or electricity

Fossil fuel

Nonrenewable energy formed from ancient organic matter

Types of fossil fuels

Coal/peat, petroleum, natural gas

Renewable energy

Energy from naturally replenished sources

Hydroelectric power

Electricity generated by moving water

Nuclear energy

Energy released from changes in atomic nuclei

Commercial energy source

Energy that is bought and sold

Subsistence energy source

Energy gathered for personal use

Global fossil fuel use

Approximately 82 percent of global energy consumption

Largest energy users in total

The United States and China

EROEI

Energy return on energy investment

First law of thermodynamics

Energy cannot be created or destroyed

Second law of thermodynamics

Usable energy decreases during transformations

Energy inefficiency

Energy lost as heat during processing and use

Coal-fired power plant

Burns coal to produce steam that turns a turbine

Combined cycle power plant

Uses gas and steam turbines together to generate electricity

Disadvantages of combined cycle power plants

Thermal pollution from heated water

Capacity

Maximum electrical output of a power plant

Solutions to solve thermal pollution of combined cycle

Using CO2 to replace steam; using a cooling tower; cogeneration

Capacity factor

Fraction of time a plant operates annually

Coal

Most abundant and dirtiest fossil fuel

Types of coal

Peat, lignite, bituminous, anthracite

Advantages of coal

Energy-dense, plentiful, easy to transport

Disadvantages of coal

CO2, SO2, and toxic metal emissions

Petroleum

Liquid fossil fuel from ancient marine organisms

Shale source rock

The layer of rock where petroleum is initially formed

Sandstone reservoir rock

The layer of rock that absorbs the petroleum and drags it up

Shale cap rock

The layer of rock that stops the petroleum from going higher up

Advantages of petroleum

Convenient to transport and use; cleaner than coal

Disadvantages of petroleum

CO2 emissions and spill risk

Hydraulic fracturing

Cracking rock using pressurized fluid to extract oil or gas

Disadvantages of fracking

Aquifer contamination

Natural gas

Fossil fuel primarily composed of methane (80%)

Advantages of natural gas

Cleaner burning than coal

Disadvantages of natural gas

Methane leakage and water contamination

Tar sands

Mixture of mostly sand, clay, water, and bitumen (hydrocarbons)

CTL (coal to liquid)

Converting solid coal into liquid fuel

Energy intensity

Energy use per unit of GDP; dropping in recent years

Hubbert curve

Predicts timing of peak oil extraction

Nuclear fission

Splitting heavy nuclei to release energy

Uranium-235

Primary fuel used in nuclear fission

Advantages of nuclear power

No air pollution during operation

Disadvantages of nuclear power

Accident risk and waste disposal

Radioactive waste

Spent nuclear fuel that emits radiation

High-level nuclear waste

Spent fuel rods

Nuclear waste storage

Fuel rods stored underwater

Biomass energy

Energy derived from organic matter

Advantages of biomass

Cheap and accessible

Disadvantages of biomass

Deforestation and air pollution

Passive solar design

Building design that captures solar energy naturally

Photovoltaic system

Converts sunlight directly into electricity

Advantages of solar energy

No CO2 or air pollution

Disadvantages of solar energy

High cost and storage issues

Wind energy

Electricity generated by wind turbines

Advantages of wind energy

Clean, renewable, and low input

Disadvantages of wind energy

Noise, wildlife impacts, storage needs

Energy conservation

Reducing energy use through efficiency

Peak demand

Greatest energy use at one time

Smart grid

Efficient, self-regulating electricity distribution system

Tiered rate system

Higher energy use leads to higher prices

Hydrogen fuel cell

Fuel cell converts fuel such as hydrogen into an electrical current

Electrolysis

The application of an electric current to water molecules to split them into hydrogen and oxygen

Advantages of HFC

Clean and renewable

Disadvantages of HFC

Explosive, expensive, and not efficient