Chapter 17 Flashcards
net energy
total amount of useful energy available from an energy resource or energy system over its lifetime, minus the amount of energy used (first energy law), automatically wasted (second energy law), and unnecessarily wasted in finding, processing, concentrating, and transporting it to users.
net energy ratio
the higher the ratio, the greater the net energy. When the ratio is ess than 1, there is a net energy loss.
petroleum (crude oil)
gooey liquid consisting mostly of hydrocarbon compounds and small amounts of compounds containing oxygen, sulfur, and nitrogen. extracted from underground accumulations, it is sent to oil refineries, where it is converted to heating oil, diesel fuel, gasoline, tar, and other materials.
conventional oil (light oil)
provide us with food grown with the help of hydrocarbon-based fertilizers and pesticides.
heavy crude oil
remaining heavy crude oil is too difficult or expensive to recover. as oil prices rise, it can become economical to remove about 10-25% of this reming heavy oil by flushing the well with steam and water.
refinery
after crude oil is extracted, it is transported to a refinery by pipeline, truck, or ship (oil tanker. there it is heated and distilled in gigantic columns to separate it into components with different boiling points.
petrochemicals
some products of oil distillation, are used as raw materials in manufacturing pesticides, plastics, synthetic fibers, paints, medicines, and many other products.
Arctic National Wildlife Refuge (ANWR)
contains more than one-fifth of all land in the U.S. National Wildlife Refuge System.
oil sand (tar sand)
is a mixture of clay, sand, water, and a combustible organic material called bitumen.
bitumen
a thick and sticky heavy oil with a high sulfur content and that smells like asphalt.
shale oil
slow-flowing, dark brown, heavy oil obtained when kerogen in oil shale is vaporized at high temperatures and then condensed. Shale oil can be refined to yield gasoline, heating oil, and other petroleum products.
natural gas
is a mixture of 50-90% by volume of methane (CH4), the simplest hydrocarbon. also contains smaller amounts of heavier gaseous hydrocarbons such as ethane (C2H10) and small amounts of highly toxic hydrogen sulfide (H2S).
conventional natural gas
lies above most reservoirs of crude oil.
unconventional natural gas
is found in other underground sources.
liquefied petroleum gas (LPG )
when a natural gas field is tapped, propane and butane gases are liquefied and removed.
liquefied natural gas (LNG)
at very low temperature natural gas can be converted to LNG. highly flammable liquid can then be shipped to other countries in refrigerated tanker ships.
coal
is a solid fossil fuel formed in several stages as buried remains of land plants that lived 300-400 million years ago were subjected to intense heat and pressure over many millions of years.
area strip mining
is used to extract coal found close to the earth’s surface on flat terrain.
contour strip mining
is used to extract coal on hilly or mountainous terrain. in some cases entire mountaintops are removed and dumped into valleys below to expose seams of coal.
peat
(not a coal) partially decayed plant matter in swamps and bogs, low heat content
lignite
(brown coal) low heat content; low sulfur content; limited supplies in most areas.
bituminous coal
(soft coal) extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content.
anthracite
(hard coal) highly desirable fuel because of its high content and low sulfur content; supplies are limited in most areas.
synthetic natural gas (SNG)
gaseous fuel containing mostly methane produced from solid coal
coal gasification
conversion of solid coal to synthetic natural gas
coal liquefaction
conversion of solid coal to a liquid hydrocarbon fuel such as synthetic gasoline or methanol
light water reactors (LWRs)
produce about 85% of the world’s nuclear-generated electricity (100% in the United States)
uranium oxide fuel
in each pellet consists of about 97% non fissionable uranium-238 and 3% fissionable uranium-23.
control rods
made of neutron-absorbing materials, such as boron or cadmium, are moved in and out of the spaces between the fuel assemblies in the core to absorb neutrons.
moderator
slows down the neutrons emitted by the fission process to keep the chain reaction going.
pressurized water reactors
the moderator can be liquid water (used in 75% of the world’s reactors.)
coolant
usually water, circulates through the reactor’s core to remove heat to keep the fuel rods and other materials from melting and to produce steam for generating electricity.
containment vessel
used as a further safety backup, with very thick and strong walls surrounds the reactor core. designed to keep radioactive materials from escaping into the environment in case of an internal explosion or core meltdown within the reactor and to protect the core from external threats.
water filled pools (dry casks)
with thick steel walls are used for on-site storage of highly radioactive spent fuel rods removed when reactors are refueled.
high level radioactive waste
give off large amounts of harmful ionizing radiation for a short time and small amounts for a long time.
decommissioned
retired, if a plant’s life cannot be extended by expensive renovation, it will be retired.
low level radioactive waste
give off small amounts of ionizing radiation and must be stored safely for 100-500 years before decaying to safe levels.
