ENVS 101 Exam 3

Describe the three different ways to generate electricity using ocean energy.

-Tidal power is basically dams with turbines that are turned by the movement of tidal water in and out of basins. -Wave power which is converts the kinetic energy of waves to electricity by turning pumps or turbines. -Ocean thermal energy conversion uses the difference in temperature between the surface and deep water to heat liquids and turn turbines.

Concentrating Solar Power Systems (CSPs)

A method of generating electricity from sunlight that relies on mirrors to concentrate the sun's rays on a tower or a series of pipes that hold water or another fluid. The concentrated sunlight heats the fluid to boiling, producing steam. The steam is then used to spin a turbine and generate electricity.

Gyres

A pattern of circulation in surface ocean waters that is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Anthropocene epoch

A term used by some scientists to designate the current geologic epoch in which human impacts on Earth's environment are pervasive

Kerogen (14.3)

A waxy organic substance that is a precursor to oil and natural gas

Describe the advantages and disadvantages of using biomass energy.

Advantages: carbon neutral in theory (carbon os released but it is equal to plants during photosynthesis); help reduce acid rain and smog because of lower emissions from combustion; the supplies are abundant. Disadvantages: carbon is still released, people ignore the other greenhouse gases emissions during biofuel production -like the the emissions during transportation of material

Describe the advantages and disadvantages of using solar energy.

Advantages: free and limitlessly available; no pollution or greenhouse gases (at least to generate the power); creates local jobs that cannot be outsourced to other countries Disadvantages: High upfront costs to install panels or build CSPs; producing PV panels requires a lot of energy and uses potentially toxic heavy metals; energy is intermittent, no sun at night

Describe the advantages and disadvantages of using wind power.

Advantages: no fossil fuels, pollution or greenhouse gases; EROI on building a wind turbine is 20-22; power is generated domestically and locally Disadvantages: increase killing of flying animals that collide with turbines; power is inconsistent, dependent on the wind; some folks argue turbines are unsightly and they're often most useful in places of natural beauty

Describe the advantages and disadvantages of using hydropower.

Advantages: no fossil fuels, pollution or greenhouse gases; cheap to operate once the original investment has been made to build the plant; impoundment facilities can regulate how much water is released by dam thus how much power is made; flood control Disadvantages: reservoirs take up riparian habitat, can increase greenhouse gas emissions, can displace people; lack of flow downstream can cause problems for riparian habitats, decrease sedimentation leading to erosion, increase intrusion of salt water into estuaries; dams disrupt fish and other aquatic life migrations; water released from dam has lower quality, it's colder and has less dissolved oxygen

Describe the advantages and disadvantages of using ocean energy.

Advantages: pollution free, low greenhouse gas emissions, Disadvantages: hurt the ecosystems, limited geographically, not cost competitive

Describe how biodiesel is made.

Biodiesel is a biofuel derived from plant oils and animal fats. It's made by using alcohols (methanol or ethanol) to separate the fatty acids in the plant oils form glycerin (which can then be used to make other products like lip balm and hand soap). The methanol/ethanol is added in excess to prevent the reaction from reversing. The reacted oil becomes biodiesel and can be used as up to 20% of a fuel mix in most diesel engines or 100% in engines specifically designed to run on biodiesel.

Differentiate EROIs for all of the fossil fuels.

Coal is usually thought to have the highest EROI at 40-80. Oil is 25 for primary recovery, 8-12 for secondary recovery, and lower for tertiary and fracking. The EROI for natural gas is often just grouped with oil since they're often recovered at the same time, though fracking is changing that. The book doesn't list EROI for nuclear power, but I found some sources that say 70-100.

General circulations models (9.5)

Computer models that use mathematical equations to simulate the physical processes that determine Earth's climate and energy budget

Describe the environmental effects of extracting and burning coal.

Extracting: dangerous- cave-ins, flooding, dust, & gas explosions, hurts miners; Mine tailings - sulfide concentrates become exposed creating sulfuric acid which runs into streams hurting animals. Surface mining- hurts the above ecosystem

Describe the environment effects of extracting and burning oil and natural gas.

Extraction: risk to habitats & wild life, pollute water, Burning/use: possible spills, emitted pollutants

Greenhouse gases

Gases that efficiently capture heat in the troposphere: water vapor and carbon dioxide, methane, nitrous oxide and ozone

Differentiate between impoundment hydroelectric and run-of-river hydroelectric plants.

Impoundment, stops the flow of water and releases it to flow through turbines. Run-of-river, diverts only some of the water in the river to run through the turbines, then returns the water

Describe how solar energy can be converted into electricity for solar power -2 ways

In photovoltaic (PV) technology, light causes electrons to be emitted when it hits certain materials. This is the technology in solar panels, most of which are made of two silicon plates. When light hits one of the plates, electrons move to the other, generating electric potential and current. In concentrating solar power systems (CSPs), mirrors focus sunlight on pipes filled with liquids. The heated liquid produces steam that becomes pressurized and can be used to turn a turbine.

Coriolis effect

In reference to the atmosphere, the apparent change in wind direction due to Earth's rotation. Air moving over the ground in a straight path toward the poles appears to be deflected wets to east

Compact fluorescent lights

Lights in which an electric current causes a gas to glow; CFLs emit three to five times more light per kilowatt-hour than do incandescent fixtures.

Differentiate between the four types of coal in terms of their carbon/energy content.

Lignite is typically younger, and has had less heat and pressure; it contains 25-35% carbon and producess the least energy. Sub-bituminous contains 35-45% carbon, produces more carbon the lignite. Bituminous Coal is denser with 45-86% carbon. Anthracite has the highest energy content and is 86-97% carbon.

Global warming potential (GWP)

Measure of an individual molecule's long-term impact on atmospheric temperature relative to a molecule of CO2

Ground-source heat pumps

Method of using Earth's heat for energy by taking advantage of the fact that the upper 10 ft of earth's crust maintains a nearly constant temperature of 10-15 degrees regardless of the time of year.

Describe how oil and natural gas are formed over millions of years.

Microorganisms in shallow seas or swampy marshes die and sink to the bottom. They become covered in water and sediment and begin to decay anaerobically. Sediments continue to cover the decaying material which eventually becomes kerogen, a waxy precursor to oil. Eventually the kerogen is 2-3 miles underground over thousands of years. Below ground, it is subjected to temperatures above 200F and high pressures which cause it to form oil and natural gas over millions of years. Longer time, higher temperatures and pressures are needed to form natural gas. Eventually the oil/gas seep up toward the surface because they are less dense than water. If they reach the surface, the gas escapes and the oil becomes a tar pit. If they become trapped by an impermeable rock layer on their way toward the surface, it becomes a conventional oil reservoir.

Explain why the potential for growth in use of hydropower is weak compared to other renewables.

Most of what can be done with hydropower is already done, much more would infringe on ecosystems and biodiversity,

Describe other environmental effects of nuclear power.

Negative: disrupts large areas of land; may contaminate water; the put off heat may increase near by water temperatures effecter underwater ecosystems; risks of power plant melting/risk of nuclear contamination; Positive: Cheep energy, lots of energy; new technology to help prevent risks

(15.1) Describe the four major barriers to widespread use of renewable energy.

New technologies:we need more developments to be ready; Economies of scale: expensive; Externalized costs favor nonrenewable energy: Government pays to reduce prices of fossil fuels; -----------------

Describe how oil is extracted with emphasis on primary and secondary oil recovery.

Once an oil reservoir is located, a well is drilled through the impermeable rock layer to access the oil/natural gas. (oil and gas are usually in the same reservoirs). Primary recovery: the oil that naturally flows to the top about 20%. Secondary recovery: water is pumped into the well to cause pressure on the oil and force it out gets about 10-20% more of the oil.

Peat (14.2)

Organic material broken down anaerobically into a wet, partially decomposed mixture; becomes coal

Differentiate between passive and active use of solar energy

Passive gets energy from the sun without electrical or mechanical mechanisms and active uses mechanical mechanisms. Passive type of window to cool or heat house, active solar panels

Describe how coal is formed over millions of years.

Plant material fell into swamps and was covered by sediment and water before it could decay. First, it broke down anaerobically into a material called peat. Then thick layers of sediment formed over the peat. The high temperature and pressure forced out a lot of the water and packed the carbon compounds of the original plants closer together resulting in coal. Coal deposits carbon and energy varies depending on its age and subjected pressure and temperature.

Global warming

Refers specifically to the increase in atmospheric temperature since the late 1800s and the Industrial Revolution

Climate change (9.1)

Refers to long-time variations in climatic variables such as temperature and precipitation

Weather

Short-term variations in local atmospheric conditions

Cliamte

The atmospheric conditions such as temperature, humidity, and rainfall that exist over large regions and relatively long periods of time

Intertropical convergence zone

The band of rising air at the equator

Temperature anomaly (9.2)

The difference between each year's average temperature and the average annual temperature over 20-30 benchmark years. A positive anomaly indicates a year that is warmer than the benchmark averages and a negative anomaly represents a year that is cooler than the benchmark average.

Differentiate between sugarcane, corn, and cellulosic ethanol production.

The difference between sugarcane/corn ethanol and cellulosic ethanol is where the original sugar comes from. For sugarcane and corn, the simple sugars are extracted from the cane plant and the corn kernels. In cellulosic ethanol, the sugars come from the cellulose that makes up the cell walls of all plant cells, but some plant-y materials (like stalks, leaves, tough parts generally) have more cellulose than others (grains). The cellulose is a polymer of many glucose subunits. The glucose is easily made into ethanol, but the cellulose must be broken down first so the microorganisms can ferment the glucose subunits. Production of cellulosic ethanol would be much more efficient (using almost the whole plant that was grown) if it weren't for this challenge of degrading the cellulose before fermentation.

Tidal power (15.6)

The kinetic energy of ocean tides used to generate electricity

Atmosphere (3.6)

The layer of gases above a planet's surface

Thermosphere

The layer of the atmosphere that extends about 480 km (300 mi) into space

Stratosphere

The layer of the atmosphere that extends from 15 to about 48km (9-30mi) above earth's surface

Mesosphere

The layer of the atmosphere where the air temperature can reach lows of -173 C (-140 F) at about 90km (55mi)

Exosphere

The outer layer of the thermosphere, extending outward into space.

Active solar technologies

The use of mechanical devices to heat water and buildings or to power electrical devices to generate electricity

Passive solar technologies (15.2)

The use of the energy of sunlight without relying on electrical or mechanical devices, such as by orienting buildings so they receive maximum sunlight and using building materials that absorb sunlight to keep interior spaces warm

Dew Point

The warmest temperature at which the relative humidity of a mass of air is 100%

Describe how wind turbines work and where they are most often found.

They work by taking the kinetic energy present in air molecules. The movement of this air can be captured by the blades being pushed converting the wind to mechanical energy. That mechanical energy then turns magnets which generate an electromagnetic field that produces electricity. Found in places with lots of wind, in the hills/ mountains, near water

bituminous coal

Type of coal, denser then Sub-bituminous & lignite, 45-86% carbon

Sub-bituminous coal

Type of coal, higher energy then lignite, 35-45% carbon

anthracite coal

Type of coal, highest energy content, 86-97% carbon

Describe how 235U is extracted and refined for use as a fuel in nuclear power reactors.

Uranium ore is mined and ground into a fine powder. It is then washed in strong acid or base to remove contaminants, and the uranium-containing liquid is concentrated to make yellowcake. The yellowcake is further processed by converting the uranium into a gas, uranium hexafluoride, which is then spun in gas centrifuges to concentrate the 235U and remove 238U which does not undergo nuclear fission. The ore is about 0.7% 235U while fuel pellets contain about 4% 235U. The concentrated 235U is then packed into fuel pellets which then go into fuel rods which then go into a fuel assembly that makes up the reactor core.

Plug-in hybrid vehicles

Vehicle operating much like gasoline electric hybrids, except the battery can be recharged by plugging the car into an electric outlet.

Committed warming

Warming that would occur at a rate of about 0.1 C per decade even if we were to stop all greenhouse gas emissions immediately

Describe how natural gas is extracted with emphasis on hydraulic fracturing.

Well is drilled some flows out naturally the rest is got through hydraulic fracturing. The use of high pressure liquids to fracture the rocks, sand mixed holds the rocks open. getting the remaining gas to flow out

Biodiesel

a biofuel derived from plant oils and animal fats that can be burned in diesel engines

High Pressure

a condition of the atmosphere in which the pressure is above average

Low Pressure

a condition of the atmosphere in which the pressure is below average

Tidal barrage

a dam across the narrow outlet of a tidal basin that uses the ebb and flow of tidal waters to power turbines and dynamos to generate electricity

Renewable portfolio standards

a government mandate that a certain percentage of energy use comes from renewable energy resources, the objective of which is to help build demand for renewable technologies

Run-of-river hydroelectric plant

a hydropower facility that uses the force of river water diverted into a series of pipes to spin a turbine to generate electricity

Geologic nuclear repositories

a layer of rock in which nuclear waste and all of its toxic and radioactive elements are permanently sealed from the biosphere

Photovoltaic (PV) technology

a method of generating solar power that converts light energy into electricity through the photovoltaic effect, in which light energy causes certain materials to emit electrons, thereby generating an electric current

Holocene epoch

a name for the last 10,000 years of the Pleistocene epoch when Earth was in a warm interglacial period

Energy budget (3.7)

a system of accounting that measures all the energy entering and leaving an ecosystem or the entire Earth

Pleistocene epoch

a time of alternating cold and warm periods starting about 2 million years ago; each cycle of cold and warm lasted about 100,000 years.

Ethanol

an in demand martial because the US requires it to be mixed into our gasoline

Scrubbers

devices containing chemicals that react with pollutants such as SO2 and filter them from industrial exhausts

Impoundment hydroelectric plant

electricity generated by impounded water, such as water behind a dam, flowing downhill through a turbine

Hydroelectric power (15.5)

electricity generated by using the kinetic energy of moving water to turn a turbine

Cellulosic ethanol

ethanol that is produced from agricultural residues, wood, grasses, or other cellulose-rich feedstocks

Biofuels

fuels derived directly from plant materials, such as corn or wood

Geothermal energy (15.7)

heat energy that is generated and stored in the earth itself

Nuclear power reactor

in a nuclear power plant where the uranium is converted to power

Secondary oil recovery

injection of water to extract another 10-20% of the oil reservoir after the primary recovery stage

Describe how coal is extracted.

it is removed from sediments by mining. Surface or strip mining is the mining of coal that is 200ft or less. All deeper coal is obtained through underground mining

Light-emitting diodes LED

lights in which an electric current passes through silicone-rich materials; more efficient and longer lasting then CFL and incandescent lights

Incandescent lights (15.8)

lights in which an electrical current causes a thin metal filament to glow

Relative humidity

measure of extent to which air is saturated with water vapor, expressed as a percentage; vapor pressure/saturation vapor pressure X100

Wind Turbine

mechanical assemblies that are designed to transform air movement into electricity

Oil reservoir

oil trapped in rocks between layers of impermeable rock

Hydraulic fracturing

process to extract oil using high-pressure liquids to fracture the rocks; also called hydraulic fracking

Mine tailings

rock and debris from mining operations; often contain high concentrations of pollutants

Overburden

soil and rock overlying a useful mineral deposit

Fly ash

solid material left when coal is burned

Greenhouse gas effect (9.3)

the absorption of radiation by greenhouse gases and trapping of the heat in the troposphere

235 Uranium (14.4)

the decay of uranium isotope, releases large amounts of energy. Uranium is used to produce fuel rods for nuclear reactors

Biomass energy (15.3)

the energy contained in living and dead organic mater

Primary oil recovery

the extraction of crude oil pushed to the surface by built-up pressure in the reservoir

Atmospheric pressure

the force caused by the pull of gravity on a column of air. more pressure the more air that is above, lower= more pressure

Spent fuel rods

the high-grade uranium fuel in the rods becomes useless and must be replaced

Wave power

the kinetic energy of ocean waves is used to generate electricity

Troposphere

the lowest layer of the atmosphere based on differences in temperature and chemical properties

Little ice age

the time between A.D. 1400 and about 1750 when a cold and wet period set in over the Northern Hemisphere

Solar power

the use of sunlight to generate electricity

Lignite

type of coal, younger, had had little heat & pressure, 25-35% Carbon

Wind power (15.4)

using the wind to generate electricity

Gasoline-electric hybrid vehicles

vehicle equipped with both an internal combustion engine and an electric motor powered by batteries

Yellow cake

what mined uranium is turned into to be transported and used for fuel.