Unit 6: Energy Resources and Consumption 35-37

Fossil fuels

-Derived from biological material fossilized millions of years ago --> Dead biomass from anaerobic environments build up, is buried by sediment, and forms these fossil fuels.

-Coal, oil, and natural gas

Nonrenewable energy

-A source of energy that is a finite supply capable of being exhausted.

-Fossil fuels, Nuclear

calorie

-Amount of energy needed to raise temperature 1 gram of water 1 degree C

-1 calorie = 4.184 J

-Common uses: energy expenditure and transfer in ecosystems; human food consumption

Calorie (capital C)

-Calories in food

-1 Calorie = 1000 calories = 1 kilocalorie(kcal) = 4184 J

-Common uses: food labels; human food consumption

British Thermal Unit (BTU)

-Amount of energy it takes to heat 1lb of water 1 degree F

-1 Btu = 1,055 J

-Common uses: Energy transfer in air conditioners and home water heaters

Kilowatt-hour (kWh)

-Amount of energy expended by using 1 kilowatt of electricity for 1 hour

-1 kWh = 3,600,000 J = 3.6 MJ

-Common uses: Energy use by electrical appliances; often given in kWh per yr

Renewable energy sources

-Sources of energy able to be replaced through ongoing natural processes

-Divided into potentially renewable and nondepletable

Potentially renewable energy

-Resources that can be regenerated indefinitely if properly managed

-Wood, biofuel

Nondepletable

-Resources that cannot be used up, no matter the quantity and rate of use

-Wind, solar, hydroelectric, geothermal

Energy use trend

-Globally, 80% of energy is produced by oil, coal, and natural gas.

-The developed nations of the world use more than 40% of the world's energy, even though they only comprise of 20% of the population.

Renewable Energy Resources in the US

-In the United States, Energy has transitioned from: Wood → coal → oil → natural gas

-None of the resources have ever stopped being used entirely, but have diminished in the amount of energy provided as compared to other resources.

-Energy can vary regionally and seasonally:

-^Coal remains the primary fuel source in southeastern and some western states

-^northern and some western states use a mix of nuclear fuels, dams, and natural gas

-Natural gas is the fastest-growing resource used today.

Energy intensity

-The energy use per unit of gross domestic product

Fossil fuel combustion

-The products of the chemical reaction of oxygen and fossil fuels --> energy, water and carbon dioxide

The Hubbert curve

-A graph that represents when world oil production will reach as maximum, leading to peak oil, where more than half of reserves will be used

Energy conservation

-Finding ways to use less energy

Energy efficiency

-Finding ways to get the most out of energy used.

Source of energy is dependent on

-The intended use

-Transportation → gasoline or diesel fuel from oil

-Home energy → wood, natural gas, or coal

-Energy is lost in transferring it into another form; recall the first and second laws of thermodynamics --> energy can only be transformed, entropy inc.

energy return on energy investment (EROEI)

-Calculates energy efficiency or the amount of energy we get out for every unit of energy that goes in

-Energy obtained from the fuel/ Energy invested to obtain the fuel

Biofuels

-Biomass that gets processed and refined into liquid fuels like biodiesel and ethanol.

-Biofuels and other biomass make up 40% of renewable energy and 5% of all energy consumed in the US today.

The sun

-The ultimate source of most energy sources

Atmospheric carbon concentrations

-Both fossil fuels and biomass raise atmospheric carbon concentrations.

-Carbon recently found in atmospheric biomass is modern carbon.

-Carbon that was contained in fossil fuels for millions of years and has recently been released is fossil carbon.

Carbon neutral

-Most biomass and biofuels --> they don't change carbon dioxide concentrations.

Common fuel types include:

-Wood --> provides heating and cooking to 2-3 billion people in the world (currently, forests are cut too fast to allow trees to maintain carbon neutrality.)

-Coal/Peat

-Natural Gas

-Crude Oil

-Tar Sands

Coal

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

-It is typically used for electricity generation and industrial processes, and can be found in many forms:

-^Peat, lignite, bituminous coal, anthracite

Peat

-Partly-decomposed organic material, like mosses

Lignite

-Soft sedimentary rock with traces of plant structure (60-70% carbon), also called brown coal

Bituminous coal

-Black or dark brown coal has bitumen, known as asphalt

Anthracite (hard coal)

-Contains greater than 90% carbon, highest in energy per volume

Natural gas

-Considered a cleaner source of combustion due to its smaller amount of particulates, sulfur dioxide, and carbon dioxide than coal or oil.

-Most of the gas is methane (CH4) and the remaining is ethane, propane, and butane.

-It can be compressed and liquified for transport.

-Natural gas comprises 24% of total energy consumption globally.

-Produces the most electricity in the US

Crude oil

-A mixture of hydrocarbons such as oil, gasoline, kerosene, as well as water and sulfur, that exists in a liquid state underground and when brought to the surface.

-Oil is used in vehicles and can be refined into a variety of compounds.

-Through a process of boiling, you can get a variety of compounds:

-^Tar

-^Asphalt

-^Gasoline

-^Diesel

-^Kerosene

Tar sands/oil sands

-Slow-flowing, viscous deposits of bitumen or asphalt, mixed with sand, water, and clay.

-Due to oil near the surface, it no longer flows, and is mixed with sand and soil.

-It is extracted at the consequence of serious negative environmental impacts throughout the mining process (fracking)

Use of energy: transportation

-35% of energy use in the US is for the transportation of people and goods.

-Public transportation is the most efficient method of transportation.

-Single driver cars and larger vehicles like SUVs and trucks are least efficient.

-Electric cars and plug-in hybrid cars make use of electricity as an energy source.

Energy carrier

-A source like electricity that can move and deliver energy in a convenient, usable form to end users.

-Energy conversion is only about 36% efficient, and fossil fuels can release many pollutants in this process.

-All thermal powerplants work the same basic way: converting potential energy into electricity.

Combined cycle

-Some natural gas-fired power plants use both a steam turbine and separate turbine powered by exhaust gases to generate more efficient electricity

Capacity of a powerplant

The maximum electrical output it can handle.

Capacity factor

The fraction of time a plant operating in a year is known

Cogeneration/combined heat and power

-One way to increase efficiency of a fuel source

-Generate electricity use "waste" heat to power a building or industrial process.

Fossil Fuel and Ore Locations

-Fossil fuels are not found everywhere; only in certain locations.

-Coal forms only through organic matter becoming buried quickly.

-Places that were tropical areas (wetlands, river deltas, etc.) millions of years ago are the locations where coal is found today:

-^United States

-^Russia

-^China

-^Australia

-^India

Crude oil/petroleum

-Formed from ocean-dwelling phytoplankton (microscopic algae).

-Oil is found in porous rock covered by nonporous rocks.

-Natural gas is typically found above petroleum.

-Oil consumption is at 4 billion gallons per day, of which the US uses 21%.

-Top producers of petroleum are:

-^United States

-^Saudi Arabia

-^Russia

-^Canada

-^China

Advantages of coal

-Energy dense

-Plentiful

-Provides heat to industrial processes and electricity generation

-Mining is low cost

-Easy to move

Disadvantages of coal

-Tailings have enviromental consequences

-Subsurface mining is expensive and dangerous

-Impurities of coal can be harmful: sulfur, Hg, Pb, As

-Pollutants like sulfur dioxide and particulates are released through burning

-Carbon in coal is converted into carbon dioxide, contributing to climate change

Advantages of oil

-Liquid form is easy to transport and use

-Energy-dense

-Cleaner-burning than coal

-Ideal fuel for mobile combustion engines

-Produces only 85% as much carbon dioxide as goal

Disadvantages of oil

-Also contains sulfur and other trace metals

-Oil may leak into ground or ocean when extracted

-Tankers and pipeline may break or spill

-Habitats can be destoryed to mine for oil or to create pipelines to transport it

-Oil flaring --> burning off excess natural gas --> can lead to air pollution

-Still emits carbon dioxide

Advantages of natural gas

-Extensive gas pipeline system already in place

-Fewer impurities than coal and oil

-Almost 0 amounts of sulfur dioxide and particulates released

-Only released abt 60% as much carbon dioxide as coal

-Can be liquified to provide fuel for homes and businesses

Disadvantages of natural gas

-Unburned natural gas (methane) can be released and is 25x more potent than carbon dioxide

-Extraction leads to large extraction fields, destroying habitat

-Hydraulic fracturing can contaminate the water table

-water used in the fracking process is contaminated instead of being used for homes and businesses

-Fracking releases volatile organic compounds VOCs which evaporate quickly at atmospheric temps

Coal burning fire powerplant steps

1. Coal is delivered to a boiler and burned

2. Energy is transferred to water by heat

3. Water becomes steam

4. The steam turns a turbine

5. The turbine is attached and turns a generator to produce electricity

6. The electricity generated is transported along a network of transmission lines known as the electrical grid

7. Steam is condensed back into water and sent to a cooling tower or cooling pond

Calculating energy efficiency

Coal to electricity x transport of electricity x light bulb efficiency = overall efficiency

Energy quality

-The ease with which an energy source can be used to do work.

-Higher quality of energy sources don't require too much energy to move it from one place to another.

-Gasoline is a high-quality energy source due to its concentrated energy and current infrastructure to transport it.

-Wood is lower quality due to low concentration of energy and the challenge it takes to transport it.