Energy Concepts Energy, forms, power units, conversions, and laws of thermodynamics Energy Consumption History – Industrial Revolution, exponential.

ENERGY RESOURCES AND CONSUMPTION

Areas Tested Energy Concepts

Energy, forms, power units, conversions, and laws of thermodynamics

Energy Consumption History – Industrial Revolution, exponential growth,

and energy crisis Present global energy use Future energy needs

Fossil Fuel Resources and Use – formation of coal, oil, and natural gas, extraction/purification methods, world reserves and global demand, synfuels, and environmental advantages/disadvantages of sources

Nuclear Energy – nuclear fission process, nuclear fuel, electricity production, nuclear reactor types, environmental advantages/disadvantages, safety issues, radiation and human health, radioactive wastes, and nuclear fusion

Hydroelectric Power - dams, flood control, salmon, silting, and other impacts

Energy Conservation - energy efficiency, CAFE standards, hybrid electric vehicles, and mass transit

Renewable Energy - solar energy, solar electricity, hydrogen fuel cells, biomass, wind energy, small-scale hydroelectric, ocean waves and tidal energy, geothermal, amd environmental advantages/disadvantages

Energy Concepts See packet for energy forms and units See free-response for and example of a

conversion problem MW to kW to kWh/yr

First Law of Thermodynamics Energy can not be created or destroyed

Second Law of Thermodynamics When energy is converted from one form to

another a less useful form results Most of the energy lost is lost as heat and is

considered low-quality energy

Energy Consumption

History wood was the predominant form of energy

until the Industrial Revolution During the Industrial Revolution coal became

the primary source 20th century has seen petroleum overtake coal

but natural gas and coal has seen an increase in the later half of the 20th century

Present Global Use US was self-sufficient until the late 1950s Industrial, Transportation, residential and

commercial (greatest to least amount used) US accounts for 25% of the world consumption

of petroleum (tar, oil, and natural gas) See comparison chart of production vs

consumption Future Energy Needs

The forecast is a continued reliance of oil, natural gas and coal

Viable resources are clean coal, methane hydrates, oil shale, and tar sands

Clean coal This technology refers to the process that

reduces the negative environmental impact of burning coal

The coal is washed and the sulfur dioxide and carbon dioxide gas is captured (see picture)

Other forms of clean-coal technology has to do with natural gas or microbial fuel cells which are charged from biomass or sewage

Methane Hydrates Methane locked in ice – found in permafrost

and deep beneath the ocean floor Type of natural gas can create a greater

amount of carbon dioxide a greenhouse gas

Oil Shale Contains an organic material called kerogen

that converts to oil in the absence of air Net energy considered moderate due to the

energy needed to put into extracting it Huge negative environmental impact due to

surface mining Can be mined underground through heating it

in the ground and extracting the oil and gases though this can affect aquifers

Tar Sands Contain a semisolid form of oil called BITUMEN Similar issues with oil shale – oil in tar sands

represents two-thirds of the world’s total oil reserves

Fossil Fuel Resources and Use

Coal Produces by ancient organic matter (286

million year old) under high temperature and pressure

Lignite – softest and lowest heat content Subbituminous – lower sulfur content leading

to cleaner burning fuel Bituminous - high sulfur content and most

plentiful in the US – use to make electricity Anthracite – hard and high heat component

and relatively low sulfur content – home heating least amount

Oil Fossil fuel produced by the decomposition of

deeply buried organic material under high temperature and pressures for millions of years

Natural Gas Known as methane produced by

decomposition of organic matter under high temp and pressure usually found along with oil reserves

Can be liquefied mainly for easy worldwide distribution

Extraction-Purification Methods Coal – largest in China

Surface mining and underground mining Removal of foreign material, screening for size,

crushing, and washing to remove contaminants Oil – Middle East

Expensive machinery used to drill a well…initially high pressure and later pumped

Sent to a refinery to be ‘cracked’ which is where it is separated by its boiling points (see picture)

Natural Gas – Russia and Kazakhstan Flows from wells under its own pressure and is

collected by small pipelines that feed into the large gas transmission pipelines

Removal of water and condensates

Synfuels Liquid fuel synthesized from a non petroleum

source such as coal (shale oil and synthetic natural gas)

Pros Easily transported through pipelines Produces less air pollution Large supply of raw materials to meet current demands for

hundreds of years Can produce gasoline, kerosene, or diesel directly without

cracking or refining Cons

Low net energy yield and use of energy to produce most Plants are expensive and increase depletion of coal More expensive product than petroleum products

Nuclear Energy

Nuclear fission – an atom splits into two or more smaller nuclei along with by-product particles (neutrons, photons, gamma rays, and beta and alpha particles)

If controlled – heat produced makes steam that turns generators that produce electricity

If NOT controlled – nuclear explosion

Nuclear Fuel

U-235 – called enriched uranium, nuclear weapons contain 85% or more, nuclear power plants contain about 3%

U-238 – most common isotope, hit with neutrons to decay into Pu-239, most depleted uranium

Pu-239 – 1/3 of energy produced in a typical commercial plant, amount of Pu-239 produced is regulated and control rods have to be changed frequently due to the build up of Pu-239 and Pu-240 – can be used for nuclear weapons

The US produces the most nuclear energy but it only makes up 19% of the energy we consume

France produces the highest percentage of what it consumes at 78%

Types of reactors

Light-water, heavy-water, and graphite-moderated Common features

The core contains up to 50,000 fuel rods each stacked with many fuel pellets

Uranium oxide is the fuel: 97% U-238 and 3% U-235 Control rods move in and out to absorb neutrons and slow

down the reaction Neutron moderator is a medium that reduces the velocity

of fast neutrons making them capable of sustaining a nuclear chain reaction (water, graphite – produces plutonium for weapons, or deuterium oxide – heavy water)

Coolant removes heat and produces steam to generate electricity

See the Price-Anderson Nuclear Indemnity Act - 1957

Health Risks

Premature death per year Nuclear – 6,000 Coal – 65,000

Genetic defects/damage Nuclear – 4,000 Coal – 200,000

Nuclear Fusion

Two or more atomic nuclei joining together to form a single heavier nucleus

Not yet controlled enough for use as nuclear power

Hydroelectric Power Supplies 10% of the electricity in the US and 3%

worldwide Flood control

Channelization Dams Identify and manage flood-prone areas Levees or floodwalls Preserve wetlands

Salmon Migratory runs blocked and many spawning and

rearing habitats are destroyed Fish passage facilities and fish ladders to help

juvenile and adult fish migrate over or around dams

Other impacts Disease – breeding grounds for mosquitoes,

snails and flies Displacement – behind dams destroy rich

croplands and displace people Effects on watershed – downstream deprived

of nutrient-rich silt Impact on wildlife – migration and spawning

cycles Silting – forms behind the dam Water loss – evaporation and seepage

CAFE standards

Corporate Average Fuel Economy The average fuel economies of a

manufacturer’s fleet of passenger cars or light trucks

Standards have not improved since 1996 Could be expanded to include

Transition to a hybrid technology Performance-based tax credits Optimizing transmission improvements

Hybrids

Parallel hybrid – gas engine and electric engine work at the same time – Honda Insight

Parallel-split hybrid – can change back and forth with the engine charging the batteries – Toyota Prius

Plug-in hybrid – plug in each time and used first, when used up changes to fuel tank

Renewable Energy

Solar Energy Hydrogen Fuel Cells Biomass Wind Energy Small scale Hydroelectric Ocean Waves and Tidal Energy Geothermal