chapter 16: energy alternatives Flashcards
whats special about the bay of fundy?
greatest difference between low and high tide in the world
why is tidal power better than traditional hydroelectric dams?
hydroelectric dams hold water behind dams (creates many negative impacts). tidal power does not involve this, instead the water has to be retained behind the sliding gates only for brief periods
what are the concerns of tidal energy?
interference with normal currents and with marine life
what is hydroelectric power?
= uses the kinetic energy of moving water to turn turbines and generate electricity
what is the storage technique approach of hydroelectric power?
stores water behind dams
what are run of river approaches in hydroelectric power?
generates energy without greatly disrupting the flow of river water
benefits of hydropower
renewable, clean(no emission of co2), efficient EROI 10:1
what country has nuclear power as its main sourcE?
france
what is nuclear energy?
energy that holds together protons and neutrons within the nucleus of an atom
what is nuclear fission?
the splitting apart of atomic nuclei
how is nuclear fission used for nuclear power?
splitting apart the atom releases energy.
energy release heats water within the core of a reactor» This heat is transferred through heat exchangers to outer loops where steam generation is possible for generating power
what is the nuclear fuel cycle?
naturally occurring uranium is mined from underground deposits
what are control rods?
part of the process of creating nuclear energy…. soak up excess neutrons produced
why is nuclear reactor safety important?
if not regulated correctly, fuel and core materials can melt into an unmanageable mass and migrate. catastrophic release of radiation into environment
what happens during a nuclear meltdown?
coolant water is drained from the reactor vessel, temperatures rises inside the reactor core, and metal surrounding the uranium fuel rods begin to melt, releasing radiation
what are the three major events that have been most influential in shaping public opinion about nuclear energy?
three mile island, chernobyl, Fukushima Daiichi.
what was the three mile island incident?
a near-miss nuclear meltdown. the most serious event of its kind in US. multibillion dollar clean up took years, no significant health effects to residents have been noted. 1979
what was the chernobyl incident?
explosion at chernobyl nuclear plant in ukraine, most severe nuclear power plant event in the world. For 10 days, radiation escaped from the plant while crews tried to put out the fire. 31 died directly, thousands died from cancer after the event 1989
chernobyn sarcophagus
giant steel structure to isolate contaminated area from chernobyl incident. a “cover”
what was the fukashiima daiichi incident?
a 2011 earth quake in japan caused a tsunami that caused flooding of generators in fukashiima daiichi plant. overheating of reactor cores caused fires explosions and core meltdowns. trace amounts of radioactive material found in the pacific ocean.
why is radioactive waste disposal problematic?
the half-lives of uranium, plutonium,
and many other radioisotopes are far longer than human lifetimes so this high level waste will continue to emit radiation for thousands of years. radioactive
waste must be placed in unusually stable and secure
locations and monitored for many, many years.
what idea are scientists testing in Lac du Bonnet, Manitoba, for disposing of nuclear waste?
geological isolation : long-term storage deep underground in the stable, ancient crystalline rocks of the Canadian Shield
biomass
organic material that make up living organisms, can be a source of energy
what classifies a “new” renewable energy source?
not used widely, their technology is still in development
what is nuclear fusion?
involves forcing together the small nuclei of lightweight
elements under extremely high temperature and pressure, process that drives our suns output of energy…uses hydrogen from water for fuel. low pollution and waste/ not sure yet if nuclear fusion is a viable option, costs lots of money.
are fossil fuels considered biomass energy?
no. because the matter from living organisms has been decayed for millions of years
ethanol
a fuel made by fermenting biomass.. used to power cars.
biodiesel
fuel made from vegetable oil mixed with small amounts of ethanol or methanol
t/f: electricity can be generated from biomass
true
cogeneration
simultaneous production of different
forms of energy through two mechanisms operating at the same plant
land fill gas
anaerobic bacterial breakdown of waste by microbes
in landfills produces methane and other gases/. biogas can be used for electricity
pros/cons biomass energy
pro: reduces ghg emissions, cheaper
con: inefficient, affects ecosystems
passive solar energy:
buildings are designed and building materials are chosen to maximize absorption of sunlight in winter. usually involves installing southfacing
windows to maximize sunlight capture in the winter .
what is the most common way to harness solar energy?
passive solar energy
active solar energy
make use of technological devices to focus, move, and store solar energy
solar panels are passive/active solar energy
active
what is thermal mass?
= construction materials that absorb, store, and release heat
how do solar panels work?
Water, air, or antifreeze pass through the collectors, transferring heat throughout the building . heated water is stored and used for later use.
power tower
solar energy; = mirrors concentrate sunlight onto receivers to create electricity
what do photovoltaic cells do?
collect sunlight
and convert it to electrical energy by making use of the
photovoltaic or photoelectric effect.
A PV cell has two silicon plates, the n-type layer and the p-type layer
photoelectric effect
= occurs when light strikes one of a pair of metal plates in a PV cell, causing the release of electrons, creating an electric current
net metering
owners of houses with PV systems to sell their excess solar energy to their local power utility.. the value of the power the consumer sells
to the utility is subtracted from the consumer’s monthly
utility bill
what is the fastest growing energy sector?
wind power
geothermal energy
radioactive decay of elements deep
in the interior of our planet generates heat that rises to
the surface, heating rock and ground water, and generating steam to turn turbines and generate electricity
is geothermal energy inexhaustible?
technically. but If a geothermal plant uses heated
water more quickly than the ground water is recharged,
the plant will eventually run out of water.
geothermal ground source heat pumps
use thermal energy from near-surface sources of earth and water. e pumps heat buildings in the winter by transferring heat from the ground into buildings»In the summer, heat is transferred through underground pipes from the building into the ground
Currently, geothermal energy provides less than ___ of the total energy used worldwide
0.5%. more than solar and wind combined. but much less than biomass and hydropower.
electrolysis
electricity is input to split hydrogen atoms from the oxygen atoms of water molecules: 2H2O–> 2H2 + O2
produces pure hydrogen.
whats good about hydrogen power?
we will never run out of hydrogen as it is the most abundant element in the universe. can clean and non toxic, efficient
