Unit 8 Energy Vocabulary
energy
(physics) the capacity of a physical system to do work
power
(physics) the rate of doing work
energy units
joule, calorie, british thermal unit, kilowatt hour
power units
are watts and horsepower
turbine
machine that converts mechanical energy (wind, moving water, steam) into electrical energy by use of a generator
generator
A device that uses electromagnetic induction to induce electrical current by rotating loops of wire through a magnetic field
first law of thermodynamics
The principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed. Energy is neither created nor destroyed, but may be converted from one form to another (Law of Conservation of Energy)
second law of thermodynamics
a law stating that mechanical work can be derived from a body only when that body interacts with another at a lower temperature, when energy is changed from one form to another, some useful energy is always degraded into lower quality energy (usually heat).
fossil fuel
a nonrenewable energy resource formed from the remains of organisms that lived long ago; examples include oil, coal, and natural gas
natural gas
naturally occurring gaseous hydrocarbon (predominantly methane) generally produced in association with crude oil or from gas wells; an important efficient and clean-burning fuel commonly used in homes and industry
methane
colorless, odorless, flammable gas present in natural gas and formed by the decomposition of organic matter; can be produced by living organisms
crude oil
petroleum as it comes out of the ground and before it has been refined or processed into useful products.
anthracite
the cleanest-burning coal; almost pure carbon.
underground mining
involves the sinking of shafts to reach underground deposits. In this type of mining, networks of tunnels are dug or blasted and humans enter these tunnels in order to manually retrieve the coal.
strip mining
a process in which rock and soil are stripped from the earth’s surface to expose the underlying materials to be mined
natural gas pros
ample supply, high net energy yield, low cost, low pollution emissions and environmental impact, easily transported, low land use, good fuel (fuel cells, gas turbines)
natural gas cons
Releases CO2 when burned, methane can leak- pipelines, shipped across oceans (Explosive LNG), burned off and wasted because of low price
coal pros
Ample supplies, high net energy yield, low cost
coal cons
highest environmental impact, severe land use and disturbance, severe land/air/water pollution, severe human health impacts, high CO2 and CH4 emissions, mercury and heavy metals, radioactive isotopes
petroleum pros and cons
cheap, easily transported, high-quality energy. Cons: reserves depleted soon, pollution during drilling, transport and refining, land subsidence, burning oil produces CO2
nuclear fission
Nuclear change in which the nuclei of certain isotopes with large mass numbers (such as uranium-235 and plutonium-239) are split apart into lighter nuclei when struck by a neutron. This process releases more neutrons and a large amount of energy.
parts of a nuclear reactor
core, control rods, moderator, steam, generator, turbine, containment building
boiling water reactor
A nuclear reactor in which water is allowed to boil in the core. The resulting steam is used to drive a turbine generating electric power.
nuclear power pros
(A) Large fuel supply
(B) Low environmental impact (without accidents) and emits 1/6 amount of CO2 as coal
(C) Less Land disruption
(D) Low risk of accidents
nuclear power cons
Waste product (spent fuels) and other radioactive waste difficult to store and contain; Must first be stored in pools to cool the fuel or in specialized dry storage; Water used in cooling process causes thermal pollution; Half-life of uranium used for fuel is 704 million years; No long term storage yet; 9 year average between time of construction to operation
Half life
length of time required for half of the radioactive atoms in a sample to decay
meltdown
Severe overheating of a nuclear reactor core, resulting in melting of the core and escape of radiation.
thermal pollution
a temperature increase in a body of water that is caused by human activity and that has a harmful effect on water quality and on the ability of that body of water to support life
nuclear accidents
Three mile Island (U.S.) had a meltdown occurred through one half of one reactor core. Chernobyl (Ukraine) was worst, with an explosion that destroyed the reactor and sent clouds of radioactive debris into the atmosphere. Recent example Fukushima, Japan with earthquake and tsunami leading to meltdown and explosions.
radioactive waste
Particles from a nuclear reaction that emit radiation; contact with such particles may be harmful or lethal to people and must therefore be safely stored for thousands of years.
nuclear fusion
2 isotopes of light elements (H) forced together at high temperatures till they fuse to form a heavier nucleus. Happens in the Sun, very difficult to accomplish on Earth, prohibitively expensive.
hydroelectric
pertaining to the generation and distribution of electricity derived from the energy of falling water or any other hydraulic source
hydroelectric pros
renewable
electricity with no pollution
no mining
easy to make and cheap after dam is built
fish ladders
A stair-like structure that allows migrating fish to get around a dam.
issues with dams
Change rivers (Nile), canyons, wildlife. Limited lifespan (50-75 years) because of silting (buildup of sediment behind dam). Displacement of population from reservoir behind dam
National Wild and Scenic Rivers Act
-protects wild rivers and scenic rivers from development that would destroy their wild or scenic nature.
CAFE Standards (Corporate Average Fuel Economy)
these standards set mile per gallon standards for a fleet of cars; increased fuel economy = lower energy usage
hybrid vehicle
A vehicle that uses both an electric motor and internal combustion engine for propulsion. This type of vehicle gets
better gas mileage and has lower emissions than conventional
vehicles.
mass transit
solution to an urban problem; methods of moving large numbers of people. Ex: Buses, subway
passive solar
Features of ______designs are adobe walls used for heat storage, windows on the south side of the house, summer cooling vents on the roof, and flagstone floor used for heat storage.
active solar
Energy collection, which makes use of technological devices to focus, move, or store solar energy.
photovoltaic cell
solar energy cells, usually made from silicon, that collect solar rays to generate electricity
hydrogen fuel cells
combines hydrogen gas and oxygen gas fuel to produce electricity and water vapor. Fuel efficient, reduce fossil fuel use if hydrogen isn't extracted from one.
biomass
plant materials and animal waste used as fuel; wood, charcoal, animal waste
gasohol
grains fermented into alcohol and mixed with gasoline; an alternative fuel for automobiles
ethanol
a fuel made from corn and wheat that is used like gasoline but is a renewable resource
biodiesel
A diesel-equivalent, processed fuel derived from biological sources (such as vegetable oils), that can be used in unmodified diesel-engine vehicles.
wind turbine
A propeller driven by the wind and connected to a generator. The wind makes it turn the generator, which produces electricity.
wind energy pros
Clean emissions
Free energy source
Affordable power
tidal energy
energy produced by the rise and fall of ocean levels; used to generate electricity
geothermal
A resource uses the earth’s thermal energy to heat water and uses the steam to turn a generator to produce electric energy.