Unit 6 - Energy Resources & Consumption

6.1 Renewable & Nonrenewable Resources

• ==nonrenewable==: the fixed amount that cannot be replaced easily (within a humans lifespan)
  • has finite amount
  • ex. petroleum, gasoline, fossil fuels, nuclear energy (uranium)
• ==renewable==: can be replenished naturally at a reasonable rate
  • reusable, can be used indefinitely with proper management
  • ex. biomass, hydroelectric, solar, wind, waves, geothermal

6.2 Global Energy Consumption

• energy resources are unequally distributed among LDCs and MDCs
  • 20% of population = 80% of energy
  • MDCs use a lot more energy than LDCs
• fossil fuels - major/dominant source of energy (before coal)
  • ie. petroleum, coal, oil, gas
• sustainable energy sources are not projected to be major energy sources until 2040
• MDCs are very reliant on fossil fuels
  • increase in country development = increase in energy consumption
  • industrialization = demand for energy
  • due to machinery that increases efficiency and productivity
• factors for energy use depend on the country
  • availability (what sources are present?)
  • price (supply and demand)
  • government regulation (taxes, subsidies)

6.3 Fuel Types and Uses

• wood and charcoal: used in LDCs due to ease of access and little to no processing
  • abundant in these countries
  • causes soil degradation from less CO2 and deforestation
• peat: decomposed organic material that is burned for fuel
  • a precursor to coal (can be pressurized to become coal)
• there are many types of coal
  • lignite: low heat capacity, low sulfur, high moisture (worst)
  • bituminous: most commonly used, high heat capacity & sulfur
  • anthracite: best quality, high heating capacity, low sulfur (best)
• cleanest fossil fuel: natural gas
  • does not release as many harmful emissions (only releases CO2 and CH4)
  • easily transportable
• crude oil is extracted from sand, water, and bitumen in tar sands
  • not ideal for processing
  • expensive and inefficient
• specialized types of fuel: gasoline, diesel, jet fuel, heating oil, etc.
  • based on having different boiling points in refineries
• cogeneration: fuel sources used for heat + electricity

6.4 Distribution of Natural Energy Resources

• natural energy resources: coal, oil/petroleum, natural gas, ores/uranium
  • energy sources found all over the world
  • ex. Australia, Canada, Russia, etc.
• main energy source depends on energy sources in the country
• natural gas and other fossil fuels formed from pressure and heat of organic matter over millions of years

6.5 Fossil Fuels

• combustion: chemical process from burning fuel
  • fuel + O2 → CO2 + H2O
  • includes coal, oil, and natural gas
• pulverization: crushes the coal to powder → burning/combustion: done in boiler → steam in a turbine to generator → generator: converts energy to electricity (water for boiling, water for cooling)
• causes lots of environmental problems
  • destroying habitat through mining
  • pulverized coal harmful to respiratory systems and flammable
  • water depletion needed for cooling/heating
  • CO2 production → impact on climate change
  • dispersion of pollutants (mercury, sulfur)
• oil/natural gas: formed from organic matter caught under earth material
  • decomposition → gas, petroleum
  • requires mechanical pumping, drilling, and hydraulic fracturing
  • habitat destruction, potential for oil spills
• natural gas: found at many rock levels
• coal mining: dug from underground
  • surface mining: dig some land to get coal a little bit underneath
  • subsurface mining: requires machinery to dig deep into earth to find coal; habitat disruption, water contamination, frequent earthquakes
• hydrologic fracturing (fracking): method to get natural gas from the ground and bypassing groundwater reserves
  • well is made → pipe is inserted → fracking fluid (volatile compounds) → gas flows into pipe
  • causes wells/pipes to contaminate water/habitat destruction
  • VOCs harmful to the ground
  • gas leakage into atmosphere
  • causing earthquakes from added pressure
  • water depletion

6.6 Nuclear Power

• nuclear fission: usage of uranium 235 → electricity
  • splits the nucleus into separate parts to release energy (chain reaction, repeating process)
  • emits radioactive energy alongside heat
  • is not safe even after long periods of time
  • overuse: unable to create enough heat
  • remains radioactive for up to 24k years → prone to waste leaking into environment
  • ex. three-mile island (partial plant meltdown), chernobyl (full plant meltdown), fukushima (earthquake trigged nuclear explosion)
• uranium placed in fuel rods → struck by outside neutron → heat releases from uranium splitting up → heat generates steam → turns turbine → powers generator → electricity
• water can be reused through condensation (steam cools down)
  • pros: low chemical gas emissions, high power output, low cost, no mining for fossil fuels, no air pollutants
  • cons: hazardous/accident, thermal pollution, high initial cost, emissions from mining uranium, a nonrenewable source
• half-life: measure of the time for an atomic nuclear to decay

6.7 Energy From Biomass

• biomass stores energy from the sun
  • leading renewable energy source
  • converted during photosynthesis, stored in glucose molecules
  • used primarily in many LDCs
  • ex. wood, peat, charcoal, crop residue, manure
  • pros: low cost, easily accessible, used for heating/cooking
  • cons: causes many types of air pollutants, amplifies health effects (ie. respiratory illness) due to air pollutants indoors, tree for fuelwood → deforestation
• biofuels: liquid fuels made from biomass that can replace fossil fuels
  • ethanol: made from fermented plant-based sugars → alcohol
  • typically combined with gasoline (gasohol)
  • sources: corn, sugarcane, sugarbeets
  • biodiesel: modified oil from plants
  • can replace diesel fuel
  • sources: soybeans, oil palms, rapeseed
  • pros: carbon neutral, renewable, domestically produced
  • cons: low net energy, increases fossil fuels for harvesting and deforestation

6.8 Solar Energy

• photovoltaic solar energy (PV): sunlight → electricity
  • sunlight hits cell → releases electrons → releases electricity
  • pros: reduces habitat destruction, flexibility in application (ie. off the grid)
  • cons: use limited to sunlight availability, limited cell lifespan, expensive, may hurt fragile deserts
• active/concentrated solar power: red liquid heats up from sun → water turns into steam → steam turns the turbine → turbine turns a generator
  • also produces heat through house heating system
  • pros: flexibility in application
  • cons: expensive, maintenance, may hurt fragile deserts, requires high solar intensity
• passive solar: sunlight coming through windows and other parts of your home
  • produces heat, windows are strategically placed to minimize heat in summer months and maximize sunlight during winter months
  • pros: cheap, low maintenance
  • cons: difficult to implement, cannot be collected or stored

6.9 Hydroelectric Power

• kinetic energy from movement of wires and magnets in systems
• dams/reservoirs: water has kinetic energy (KE) → KE to spin turbine → KE to spin generator
• micro hydro power: utilizes single rivers/canals as energy source
  • similar to dams/reservoirs but much smaller scale and goes through powerhouse
• tidal power: KE from tides spins turbine underwater
  • pros: no air pollution or waste, inexpensive to maintain, the reservoir provides other services
  • cons: very expensive to construct, habitat destruction before/after building dams, disruptions migration of aquatic species, increased risk of flooding, disrupts natural river flows
  • ex. china three gorges dam

6.10 Geothermal Energy

• geothermal: using heat from Earth’s core that comes up from the crust
  • water in the injection well underground→ water turns into steam from internal heat → steam rises → KE steam turns a turbine → generator → electricity
  • pros: no CO2 emissions, not dependent on weather conditions
  • cons: limited access based on location, hydrogen sulfide release, depletion of heat, groundwater impact
• home heating: uses pump to bring heat from underground into house/building

6.11 Hydrogen Fuel Cell

• uses hydrogen as fuel to replace nonrenewable sources
  • reaction between hydrogen & oxygen → electric current
  • open container used to refuel battery with hydrogen fuel & oxygen
• hydrogen from water: electrolysis → electricity splits water into hydrogen and oxygen
• hydrogen from natural gas: splitting methane using heat → CO2 pollution
  • decreases net energy of hydrogen as a fuel source
  • net energy: amount of energy produced by the source - the energy used or lost to generate said energy
• first reaction layer: H2 added to cell → splits protons/electrons → electrons create electric current & protons move to membrane
• second reaction layer: O2 splits and combines with protons and electrons = water vapor as emission
  • pros: efficient at turning PE to ME than internal combustion engines
  • cons: expensive, production of hydrogen fuel requires some use of nonrenewable resources

6.12 Wind Energy

• KE from moving air → moves turbine → powers generator → generates electricity
  • has grown exponentially in the past 20 years
  • pros: renewable, clean, can use land for multiple uses, can be used on all types of land (ie. mountains, coasts, forests, etc.)
  • cons: limitations on flying (ie. killing birds), required maintenance, location must have consistent wind patterns

6.13 Energy Conservation

• using less energy decreases energy dependence of humans and lessens impact (footprint) on the environment
  • adjusting the thermostat to appropriate temperatures
  • using energy-efficient appliances
  • ex. energy star appliances use significantly less energy
  • use less water
  • taking shorter showers
  • doing large loads of laundry & using the cold cycle
• conservation landscaping: reducing irrigation energy, plant trees to match energy needs
  • ex. using a shade tree, matching your location/climate to compatible plants
• transportation: meeting cafe standards (corporate average fuel economy standards) (using less fuel to go more miles), electric/hybrid vehicles, ridesharing (public transportation/carpooling)
• using green building design elements (ie. solar windows, thermal mass, insulation, lightning from sun, green roof)