APES U6

Energy + based on slides. Skipped: 6.5, 6.6, stuff after renewable

Renewable Energy Source

can be replenished naturally or at the near rate of consumption

Depletable Renewable

can run out if overused; ex: biomass (wood, charcoal, ethanol)

Nondepletable Renewable

do not run out even if overused; ex: solar, wind, hydroelectric, geothermal

Nonrenewable Energy Source

Exist in Fixed amounts on earth & can’t be easily replaced or regenerated

2 types of nonrenewable energy sources

fossil fuels and nuclear

biggest energy source

fossil fuels

Fossil fuels

fossilized remains of ancient biomass that take millions of years to form; types: coal, oil, nat gas

Nuclear

Energy generated from uranium (most commonly uranim -325) or other radioactive fuels

Renewable rate of consumption

rate of use must be at or below rate of regeneration

Why will fossil fuels run out?

We use them at a higher rate than which they regenerate

Difference in energy consumption between developing and developed countries

developed use more energy per capita basis, but developing nation use more energy in total (higher pop)

How does the average US resident’s energy consumption compares to the world average?

5x average

Main use of oil

(gasoline) so main fuel in vehicles

Main use of coal

main fuel for electricity gen

nat gas main use

secondary fuel for electricity & main fuel for heating

What is the 2nd largest global source of energy?

Hydroelectric energy (dams used to create energy)- water spins a turbine to generate electricity

What is the 3rd largest global source of energy?

Nuclear - uranium fission releases heat to turn water into steam to turn a turbine to generate electricity

What fuel do less developed nations typically rely on?

subsistence fuels

What are subsistence fuels?

biomass (wood, charcoal, dried animal manure) that can easily be gathered/purchased

What factors affect energy source usage (especially fossil fuels)?

Availability which how many known reserves there are (nat gas increase bc fracking) and price (coal)

Can government directly raise or lower prices of energy sources?

NO

How can the government affects prices of energy sources?

taxes (to discourage usage), rebates or tax credits (to encourage companies to build renewable energy power plants)

How are biomass fuel sources used in developing countries and why are they used?

They are easily accessible (can be found and gathered by hand); often used as a home heating or cooking fuel

What are the 2 most common fuel types in developing nations? (spec)

wood and charcoal

How is wood used as an energy source and why is it used?

it is free/cheap to cut down and utilize as fuel; (neg) can cause deforestation & habitat loss

How is charcoal used as an energy source and why is it used?

It is made of heating wood under low oxygen conditions for a long time

What is peat?

It is partially decomposed organic matter (often ferns or other plants) found in wet, acidic ecosystems like bogs and moors. It can be dried and used as a biomass fuel source

How is coal formed over time?

Pressure from overlying rock & sediment layers compacts peat into coal over time

What is the order of the different types of coal from highest density & quality to least?

(on top is peat but that isn’t coal type) lignite → bituminous → anthracite

How does a coal reserve become more rich in energy.

The deeper a coal reserve is buried, there is more pressure from overlying rock layers & the more energy dense it is. More dense coal = hotter/longer fire= more steam = more electricity

What is the most valuable form of coal?

anthracite

How is Natural gas formed?

From the decaying remains of plants and animals (mostly marine life) are buried under lyaers of rock & covered by pressure into oil (petroleum) and natural gas over time

What is natural gas mostly composed of and where is it found

methane (CH₄) and in the top of trapped oil (petroleum) deposits

What is on top of oil and natural gas

a layer of sedimentary (impermeable) rock that traps the oil gas part from escaping

What is natural gas known for (pro)

“cleanest” fossil fuel (produced the fewest air pollutants 7 least CO₂), ½ amount of CO₂ than coal, no PM (ash/soot), produce less SO_x, NO_x, & no mercury (unlike other ff)

How is crude oil (petroleum) formed

decaying organic matter trapped under rock layers which is compressed into oil over time

How is oil extracted

drilling a well through the overlying rock layers to reach the underground deposit and then pumping liquid oil out under pressure

Where can oil also be found (alternative way)

in tar sands (combination of clay, sand, water, and bitumen), extracting & using oil this way is extremely energy and water intensive

How is extracting tar sands super water intensive?

lots of water needs to be heated (requires lots energy too) to create steam thats piped down into the tar sand to melt the bitumen into a liquid that can flow up a pipe + water is used to separate oil from all of its impurities at the refinery

what is bitumen

it is a thick, sticky semi-solid form of petroleum (not liquid)

fractional distillation

when crude oil (petroleum) is converted into lots of different products

how does fractional distillation work

crude oil is burned in a furnace → vapor passes into a column where different hydrocarbons are separated based on their boiling points→ hydrocarbons w/ lower boiling points father at top of column and lower gather at bottom → crude oil is used to make diff products

What are the different products made from crude oil?

petroleum gas, gasoline (car fuel), naphtha (plastic mat), jet fuel, diesel fuel, etc

What is the order of fossil fuel from most abundant to least?

coal (most) → nat gas → oil

Hydraulic fracturing

It is a method of natural gas extraction that has extended access to natural gas

how does fracking work

gas trapped in semi-permeable sedimentary rock layers, such as shale, is released by cracking the rock (fractures) with pressurized water (fracking fluid) to make it more permeable, nat gas is collected at surface, flow back water (fracking fuel) flows back out and is collected in containers or ponds nearby

Why is fracking so op (good)

increased natural gas reserves (known amount of smth)

Tar/oil sands

they are bitumen deposits where crude oil can be recovered but with higher water & energy input (isn’t as helpful as shale reserves)

Fossil fuel combustion

reaction with oxygen & fossil fuels (hydrocarbons) that release energy as heat and produced CO₂ & H₂O as products

how is combustion part of the carbon cycle

hydrocarbons in ffs reacts with O₂ in air to form CO₂

Biomass

organic matter (wood/charcoal, dried animal waste, dead leaves/brush) burned to release heat- primarily for heating homes/cooking

biofuels

liquid fuels (ethanol, biodiesel) created from biomass (corn, sugar cane, palm oil)

What can act as replacement for fuel sources?

biofuel can replace these sources such as gasoline in vehicles

How is energy generated (spec with ffs)

fossil fuel burned (or whatever thingie gets burned) → get heated→ heat warms water → water becomes steam → steam turns turbine → turbine powers a generator → generator produces electricity

Environmental consequences of coal

habitat destruction from clearing land for mining, producing pollutants, PM (soot, ash), toxic ash with lead, mercury, and arsenic, SO_x & NO_x, and Co₂ from when it gets burned

how efficient is nat gas and coal

coal is 30% efficient as a fuel source for electricity (30% of energy from bonds from the hydrocarbons are converted) and nat gas is 60% efficient (both lost a lot of energy as heat)

Cogeneration

when the heat produced from electricity generation is used to provide heat (air & hot water) to a building; (produce electricity and heat at same time)

Environmental consequences of tar sands

habitat destruction of lands that were cleared, ground or nearby surface’s water is depleted (tailings can contaminate water and runoff and lead to acid mine drainage and be toxic for animals and plants)

environmental consequences of crude oil/petroleum

possibility of spill (from tanker ships or pipelines breaking when transported as liquid) → spills in water cover sun and suffocate many ocean animals + spills in land are toxic to plant root and contaminate surface or groundwater (w/ hydrocarbons), habitat loss or fragmentation when land is cleared for roads, drilling equipment, and pipelines (for extraction and transportation of oil)

environmental consequences of fracking

possibility of well leaking, contaminating groundwater with fracking fluid → ponds can overflow with fracking liquid, depletion of ground or surface water nearby (used as fracking fluid)

How does nuclear fission work?

A neutron is fired into the nucleus of a radioactive (unstable) element, such as Uranium

then the nuclear breaks apart and releases lots of energy (heat) + more neutrons break more nuclei apart → more energy (chain reaction)

Radioactive Half-life

the amount of time it takes for 50% of a radioactive substance to decay (breakdown)

What are the purpose of the control rods in generating electricity with nuclear power plants?

They are lowered into a reactor core to absorb neutrons and slow down the reaction, preventing meltdown (explosion)

What is the purpose of the water pumps in generating electricity with nuclear power plants?

They bring in cool water to be turned into steam and also cools down the reactor to prevent overheating

What is the purpose of the cooling tower in generating electricity with nuclear power plants?

The tower allows steam from turbine to condense back into liquid and cool down before being reused (this gives off H₂O vapor)

Pros of nuclear energy

no air pollutants (PM, SO, NO) or CO₂/CH₄ from mining or plant construction, only gas released is water vapor (which is only a very weak ghg)

Drawbacks of nuclear energy

Spent fuel rods are radioactive for millions of years after they are used, mine tailing can contain radioactive elements that can contaminate water or soil nearby, a lot of water is used which can deplete local or groundwater sources, and (###) thermal pollution can happen which is hot water released from the powerplant into the surface water and cause thermal shock

Nuclear Meltdown

Is when the nuclear reactor gets severely overheated and result in core damage from overheating in nuclear power plants

Examples of nuclear meltdowns (list)

Three mile Island (US), Fukushima (Japan), and Chernobyl (Ukraine)

Three Mile Island

(least fatal nuclear meltdown) partial meltdown due to testing error, radiation released but no deaths or residual cancer

Fukushima

an earthquake and tsunami triggered cooling pump failure that lead to a meltdown

Chernobyl

(biggest nuclear meltdown) stuck cooling valve during test lead to complete meltdown (explosion of reactor core), several deaths

Geothermal Basics

Natural radioactive decay of elements deep in earth’s core gives off heat, driving magma convection currents which carry heat to upper portion of mantle, close to earth’s surface

Geothermal electricity

naturally heated water reservoirs underground are drilled into & piped up to the surface (or water can be piped down into naturally heated rock layers. magmae → heat → water into steam → thru pipe → spin turbine + water cooled in cooling tower and returned to ground to start process again after

Geothermal Ground Source Heat Pump

Heat absorbing fluid is pumped through a pipe into the ground where it either takes on heat from the ground, or gives off heat to the ground

Geothermal Heating

involves piping water deep into ground to be heated by magma & then transfering heat from water to the building (diff from ground source heat pump), go thousands of meters (km) down into ground to reach heated reservoirs

Geothermal Pros

potentially renewable (if water is piped back into the ground for reuse), much less CO₂ than ff electricity, no release of air pollutants

Geothermal Cons

not accessible in all geographic locations, hydrogen sulfide can be released (toxic and lethal to living), and costs of drilling into earth can be expensive

What is a renewable alternative fuel source to fossil fuels

H₂ gas and O₂ gas can generate electricity (with water as byproduct)

How does the hydrogen fuel cell work?

H2 gas enters fuel cell where it’s split into protons (H+) and electrons (e-) by an electrolyte membrane that only lets protons pass through. Electrons take an alternative route (circuit) around the membrane, which generates electrical current, O₂ molecules enter fuel cell and break apart indv O and 2 hydro to form h20

What is the most common application of hydrogen fuel cell

vehicles (replaces gasoline)

Creating H₂ gas

steam reform bring natural gas (CH₄) & use steam to separate H gas from methane (drawback) (emitts CO₂ & need ff input) or electrolysis- electrical current breaks water into O₂ and H₂

Hydrogen as energy carrier

-can be stored in pressurized tanks unlike renewables

-create ammonia for fertilizer

Offshore wind

wind farms in ocean or lakes + get faster winds and need transmission lines over long distances

Hydroelectricity basics

Kinetic energy of moving water 🌊 → spins a turbine (mechanical energy) ⚙ → turbine powers generator ⚡

-most renewable source of elect

-water from natural current of river, tides, of falling vertically through channels

-biggest producers: china, brazil, and us

What is energy conservation?

the practice of using energy efficiently to reduce the amount of energy required to perform a task

Small Scale Energy Conservation

lowering thermostat to use less heat in home, conserve water w/ watering plants, doing dishs, etc,

Where do oil and natural gas come from? (long time ago)

aquatic environments

Large Scale Energy

improve fuel efficiency, subsidzing (tax credits) for electric vehic;es, charning stations, and hybrids

Sustainable Home Design

deciduous shade trees (provide shade so becomes less heat), using passive solar design to heat up home, well-insulated walls, etc

Water Conservation

plant native plants (bc they require less watering), low flow showers toilets etc, and rain barrels to allow rain water to be used for watering plants of washing cars

Energy Conservation regarding transportation

vechicles have to meet CAFE (regulations set by US to require manufactures to meet certain MPG standards). Hybrid and electric vehicle have electric motor (hybrid has gasoline one too)

Rates of energy

Watt, kW, Mw, GW

order of watts

metawhats (1), kilowats (3 zeros), megawats (6 zeros), giga wats (9 zeros), and terra watts (12 zeros)

amount of energy

kWH, BTU, Therm, Kgoe

looking for power

watts or kilowatts

looking for energy

time like watthours or kilowatt hours

Passive Solar

letting the sun through windows to heat the home naturally