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)