Unit 7 - Nonrenewable Energy

Renewable Energy

Energy that can be replenished naturally, at or near the rate of consumption, and reused. If managed correctly they can be used indefinitely. Examples include solar, wind, and water

Nonrenewable Energy

Energy sources that exist in a fixed amount and involve energy transformation that cannot be easily replaced. Examples include coal, oil, and gas

Energy Efficiency

The ratio of useful energy to total energy in a system, often expressed as a percentage. It measures how effectively energy is converted into useful work, minimizing waste.

36

Percent of US energy consumption for petroleum

33

Percent of US energy consumption for natural gas

13

Percent of US energy consumption for renewable sources

10

Percent of US energy consumption for coal

8

Percent of US energy consumption for nuclear

Fossil Fuel Formation

From dead plant/organic matter under immense heat and pressure in anaerobic conditions. Petroleum and natural gas from sea life, coal from plants

Global Fossil Fuel Distribution

Coal: Former swamps, Russia and US

Oil: Sedimentary rock, Saudi Arabia, Venezuela, Canada, Russia

Gas: Sedimentary rock, Russia, US, Middle East, China

Coal

A solid fuel primarily from the remains of trees, ferns, and other plant materials preserved 280-360 million years ago

Peat

First stage of coal formation (0 years), 50m thick layer from ancient forests, vegetation buried in anaerobic conditions, partially decomposed organic matter

Lignite

Second stage of coal formation (millions of years), 10m thick, layers of peat buried deeper, compressed

Bituminous

Third stage of coal formation (hundreds of millions of years), 5m thick, lignite buried even deeper, compressed into soft form of coal

Anthracite

Final stage of coal formation (280-360 million years), 5m thick, deeper burial, increased pressure, tectonic activity, heat, hardest type of coal

Advantages of Coal

Energy-dense, plentiful, easy to exploit by surface mining, needs little refining, inexpensive, easy to handle and transport.

Disadvantages of Coal

Contains impurities, releases impurities into air when burned, contains trace metals like mercury, lead, and arsenic, combustion leads to increased air pollution, produces ash →runoff, carbon released into atmosphere

Petroleum

A fossil fuel that is cleaner than coal, found in underground deposits in a liquid mixture of hydrocarbons, water, and sulfur. Crude oil. Pumped from rigs, refined by boiling points, made into tar, asphalt, gasoline, diesel, jetfuel, and heating oil

Crude Oil

Liquid petroleum released from the ground

Advantages of Petroleum

Convenient to transport and use, relatively energy dense, cleaner-burning than coal, used in many other applications

Disadvantages of Petroleum

Releases carbon dioxide, leaks when extracted or transported, runoff enters marine waterways, releases sulfur, mercury, lead, arsenic when burned, habitat destruction

Deepwater Horizon

Largest oil spill, leaked for a month

Tar Sands

Slow-flowing, viscous deposits of bitumen (petroleum uplifted and degraded by bacteria), mixed with sand, water, and clay. Can be refined by removing water and filtering sand to obtain synthetic crude oil.

Arctic National Wildlife Refuge (ANWR)

Location in Alaska that has 25 million to 378 billion gallons of oil, tons of natural gas. Debates over habitat degradation vs economically worth it

Natural Gas

Fossil fuel found with petroleum or in separate deposits. 80-95% methane, 5-20% ethane, butane, and propane. Used to produce electricity, and in industrial processes. Nitrogen fertilizers, residences for heating homes and cooking

Hydraulic Fracturing (Fracking)

A process that involves inserting a pipe down a well, pumping in fracking fluid to break apart the ground, allowing for natural gas extraction. Can contaminate the water table, cause natural gas leaks, earthquakes, and uses water

Advantages of Natural Gas

Fewer impurities, almost no sulfur dioxide or particulants, emits only 60% as much carbon dioxide as coal, and easily transportable

Disadvantages of Natural Gas

Methane leaks contribute to greenhouse effect, exploration can contaminate groundwater, gas flaring wastes resources

Transportation

Accounts for 30% of all US energy use, primarily through petroleum products (gasoline, diesel)

Electricity Generation

40% of US energy use, uses thermal power plants

Turbine

A device with blades that can be turned by water, wind, or steam, or exhaust gas from combustion that turns a generator

Generator

Part of a power plant that converts kinetic energy (its rotating motion) into electricity

Electrical Grid

A network of interconnected transmission lines that joint power plants together and links them with end users of electricity

Capacity

Maximum electrical output of a power plant

Capacity Factor

The fraction of time a plant operates in a year

Combined Cycle

Uses waste gases for additional energy generation, 60% efficient. First cycle combusts natural gas to heat intake air which expands and flows quickly to power a gas turbine. Second cycle uses the heat generated from the combustion of the natural gas to heat water into steam which powers a steam turbine.

Cogeneration

Uses waste heat for building or water heating. 80% efficient.

Nuclear Fission

A nuclear reaction in which a large nucleus is split, releasing energy and smaller particles

Nuclear Fuel

Composed of U-235 in fuel rods

Moderator

Usually water, a substance that controls the reaction rate or a nuclear reactor and slows down neutrson

Control Rods

Metal rods (boron) that absorb neutrons and prevent a runaway reaction in a nuclear reactor

Containment Structure

A meter thick concrete/steel wall that contains radiation

Advantages of Nuclear Power

No air pollutants, no greenhouse gasses, reduces need to import oil/natural gas, higher power output

Disadvantages of Nuclear Power

Concern of radiation leaks, accidents, difficult to dispose of waste, concern about nuclear material being misused

Radioactive Waste

High and low level waste from nuclear reactors, uranium mine tailings, disposal challenges

High Level

Radioactive waste that is used fuel rods

Low Level

Contaminated clothing, tools, etc. from nuclear reactors