Energy Resources and Management Review

Nonrenewable Energy Resources (35-1)

• Characteristics:
  • Dead biomass quickly re-enters the food web and fully decomposes aerobically.
  • In swamps, rivers, and ocean floors, detritus builds up quickly and isn’t fully decomposed anaerobically.
• Usage:
  • Used because there is a lot of energy in a small volume/mass.
  • Can be converted to heat energy at a fast rate.
  • Best replacements are solar and wind energy.

Renewable Energy Resources (35-2)

• Characteristics:
  • Biomass is potentially renewable as long as it can be replenished faster than we consume it.
  • Solar, wind, geothermal, and tidal energy are non-depletable.
• Fossil Fuels:
  • Coal, oil, and natural gas are fossil fuels made from biomass that fossilized.
  • When combusted, they release fossil carbon (finite).
  • Cannot be replenished and are nonrenewable.
• Uranium:
  • Finite, because there are not enough ores for nuclear reactors.
• Historical Context:
  • Before using fossil fuels, humans relied on potentially renewable resources.

Trends of Energy Use Worldwide and in the United States (35-3)

• Top Energy Sources:
  • Oil, coal, and natural gas are the three largest energy sources.
  • They comprise 80% of total energy use.
  • Nuclear energy accounts for 5%.
• Renewable Energy:
  • Renewable energy is 15% of global energy use.
  • Hydroelectricity is the largest source of renewable energy.
• US Energy Consumption:
  • 79% fossil fuel, 9% nuclear fuel, 12% renewable resources
• Fossil Fuel Lifetime Estimates:
  • Estimates can be prepared from reserves and projected consumption rates.
  • Uncertain estimates due to new energy sources and reduced demand (human ingenuity).
  • Transition from fossil fuels to other fuels is prioritized.

Importance of Energy Efficiency and Conservation (35-4)

• Energy Conservation:
  • Finding and implementing ways to use less energy.
• Energy Efficiency:
  • Ratio of the amount of energy introduced to the system to the amount of energy that is actually used..
• Sustainable Energy Sources:
  • Avoiding the use of energy resources, conservation, and efficiency are sustainable energy sources.
• Energy Returned on Energy Invested (EROEI):
  • EROEI = \frac{\text{Energy Output}}{\text{Energy Input}}
  • Larger values signal an efficient process, while lower values signal an inefficient process.

The Sun as the Ultimate Energy Source (36-1)

• Sun's Role:
  • The sun is the energy source for many renewable fuels, including biomass, solar, wind, and hydro.
• Carbon Types:
  • Carbon in biomass is modern carbon.
  • Carbon in the atmosphere from sources buried for millions of years is fossil carbon.

Major Fuel Types and Their Uses (36-2)

• Coal:
  • Three different types of coal (peat is a precursor).
  • Derived from fossil plant material.
  • Used in electricity generation, industrial processes, and heating.
• Wood:
  • Used for firewood and charcoal, especially in the developing world.
• Natural Gas:
  • Mostly methane.
  • Used for electricity generation, industrial processes, and home use (heating interior and hot water).
• Crude Oil:
  • Extracted from the ground and can be made into compounds such as asphalt or tar sands.
  • Can be distilled to kerosene, aviation fuel, and gasoline.
• Electric Water Heaters:
  • Contain a resistance coil that makes heat inside the tank.
  • Very efficient.
• Electricity Generation Efficiency:
  • Electricity generation can have different efficiencies, so the overall process is less efficient.

Other Uses of Fossil Fuels (36-3)

• Efficiency Considerations:
  • Natural gas heaters are less efficient, but overall efficiency may be greater.
• Transportation:
  • Differing modes of transportation use different fuels and have different efficiencies.
  • One person alone in a car is more energy-intensive than more people in a car or public transport.
• Cogeneration (Combined Heat and Power):
  • Use of a fuel to generate and deliver heat to a building.
• Combined Cycle:
  • Natural gas-fired power plant that uses a steam turbine to generate electricity and a separate turbine powered by exhaust gases from natural gas combustion.

Fossil Fuel and Ore Locations (37-1)

• Organic Matter Burial:
  • Organic matter that is supposed to turn into coal or oil must be buried quickly without exposure to air (often in tropical locations).
• Geological Dependence:
  • Fossil fuel redistribution is dependent on the geology of the region.
  • Oil and natural gas are dependent on geologic events related to tectonics that make geologic domes underground.
  • Oil and gas migrate to the top of structures over time.

Advantages and Disadvantages of Fossil Fuels (37-2)

• Combustion Products:
  • Coal, oil, and natural gas release heat energy and carbon dioxide, with different pollutants released from each.
• Fracking:
  • Increased availability of natural gas in the US.
  • Leads to groundwater contamination and a suspected increase in earthquakes.
  • Causes the release of volatile organic compounds (VOCs) from both fracking fluid and machinery.

Electricity Generation from Fossil Fuels (37-3)

• Volatile Organic Compounds (VOCs):
  • VOCs are precursors to other air pollution and can harm human health (respiratory problems).
• Coal Power Plant Efficiency:
  • Modern coal-burning power plants turn potential energy of coal into electricity at 35% efficiency.
  • Leftover 65% from the coal is lost as waste heat.
• Efficiency Losses:
  • Efficiency losses occur in electrical transmission lines between house and powerplant, conversion of electricity, and lighting/computing.

Nuclear Energy for Electricity Generation (38-1)

• Process Similarity:
  • Electricity generation from nuclear energy uses a similar process as from fossil fuels.
  • Steam turns a turbine that turns a generator to generate electricity.
• Fuel Source:
  • Nuclear power uses the radioactive isotope uranium-235 as a fuel source.
• Heat Emission:
  • Uranium emits a lot of heat as it undergoes fission and decays.
• Fuel Rods:
  • Nuclear fuel is contained in cylindrical tubes (fuel rods).
• Nuclear Reactor:
  • A nuclear reactor contains hundreds of fuel rods, and heat from nuclear fission is transferred to water that turns a turbine.
• Environmental Impact:
  • Nuclear energy is a clean means of electricity generation in the context of carbon dioxide and other air pollutants.

Advantages and Disadvantages of Nuclear Power (38-2)

• Environmental Hazards:
  • Potential for accidents during plant operation.
  • Difficulty of radioactive nuclear waste disposal.
• Carbon Dioxide Emissions:
  • In the nuclear electricity generation cycle, carbon dioxide emissions are less than during electricity generation from fossil fuels.

Radioactivity and Radioactive Waste (38-3)

• Waste Disposal:
  • Due to long half-life, the safe disposal of nuclear waste is a major issue.
  • No current long-term storage facility for nuclear waste.
• Radioactive Waste Types:
  • High-level waste in the form of fuel rods.
  • Low-level waste in contaminated protective clothing and tools.
  • Uranium mine tailings and the residue left after uranium ore is mined and enriched.
• Radioactive Isotope Lifetime:
  • Each radioactive isotope has a lifetime.
  • U-235 has a half-life of 704,000,000 years.

Major Nuclear Accidents (38-4)

• Three Mile Island (1979):
  • Reactor core was severely damaged, and an unknown amount of radiation was released into the atmosphere.
• Chernobyl (1989):
  • "Run away" reactions led to an explosion and fire that damaged plants beyond use.
• Fukushima (2011):
  • 9. 0 earthquake off the coast generated a tsunami, leading to flooding and structural damage to the nuclear power plant.
  • Fires, hydrogen gas explosion, and release of radioactive gases from nuclear reactors.
  • Radioactive gases were released into the surroundings, and over 100,000 people were evacuated from their homes.

Consequences of Biomass Energy Resources (39-1)

• Overharvesting:
  • Biomass can lead to overharvesting of trees.
• Modern vs. Fossil Carbon:
  • Biomass is a modern source of carbon formed between a few years ago and a hundred years ago.
  • Fossil fuels contain carbon formed millions of years ago.
• Solid Biomass:
  • Includes wood, charcoal, and animal manure.
  • Low-quality energy sources that release particulates, carbon monoxide, and other pollutants when burned.
• Liquid Fuels:
  • Ethanol (alcohol from plant material).
  • Biodiesel (made from vegetable oils such as soybean; algae is another source).

Solar Energy Systems (39-2)

• Passive Solar Energy:
  • Takes advantage of relatively inexpensive strategies like direction windows facing a building south.
• Active Solar Technologies:
  • Use mechanical and electrical equipment to obtain heat or electrical energy from the sun.
  • High initial costs but supply large amounts of energy.
  • Large solar systems can negatively impact land, including desert ecosystems.

Hydroelectric Power (39-3)

• Generation:
  • Made from water energy like tides or waves.
  • Largest hydroelectric projects come from impounding water behind a large dam and releasing it periodically when electricity is necessary.
• Benefits:
  • Impounded water behind a dam promotes recreational and economic opportunities.
• Impacts:
  • Numerous impacts on the environment upstream of the dam.
  • Hydroelectricity can be generated from run-of-the-river systems or intertidal systems.

Geothermal Energy (40-1)

• Source:
  • Renewable and comes from the internal energy of the Earth caused by radioactive decay.
• Process:
  • Internal heat of the Earth is transferred to water and delivered to buildings for heating or electricity generation power plants.
• Benefits:
  • Does not produce pollution but does contribute to the release of gases such as hydrogen sulfide and methane.
• Limitations:
  • Access is restricted to certain locations across the globe.
  • Best in volcanic activity and tectonic plates.

Hydrogen Fuel Cell (40-2)

• Process:
  • Using a hydrogen fuel cell to make electricity requires hydrogen.
  • The waste product is only water.
• Hydrogen Production:
  • Most commercially available hydrogen is presently generated by using natural gas.
• Renewable Source Potential:
  • If made by a renewable energy source (i.e., wind, solar, water), hydrogen can be a pollution-free source of electricity.

Benefits and Impacts of Wind Energy (41-1)

• Wind Turbine:
  • Wind energy is harnessed through a wind turbine that turns kinetic energy from moving air into electricity.
• Advantages of wind enery
  Minimizing energy use through conservation and efficiency is first step to saving energy
• Wind energy is fastest growing form of new electricity generation in the world
• Disadvantages:
  • Some downsides include killing bats and birds.
  • Some people believe it causes noise and aesthetic deterioration.

Methods of Converting Energy Sources (41-2)

• Increasing Efficiency:
  • Obtaining the same amount of usable work from a device with less energy input.
  • Traveling in a hybrid electric car with the same distance as a gasoline-powered car but with less input.

Sources and Effects of Air Pollutants (42-1)

• Location:
  • Air pollution happens across the troposphere (portion of the atmosphere closest to Earth’s surface).
• Pollutant Sources:
  • Coal is the dirtiest fossil fuel and releases the most carbon dioxide, sulfur dioxide, and particulates per unit of energy obtained.
  • Oil emits fewer pollutants than coal, and natural gas releases less than oil.
  • Nitrogen oxides lead to ozone formation, smog, and acid rain.
  • Lead concentration in air decreased due to the EPA regulations banning leaded gasoline

Primary and Secondary Pollutants (42-2)

• Primary Pollutants:
  • Released directly from emission sources.
• Secondary Pollutants:
  • Undergo transformations in the atmosphere in the presence of sunlight.

Module 50 Solid Waste

• Solid waste: waste produced by humans (discarded materials that aren't liquid/gas and not toxic) and other organisms
• Municipal Solid Waste (MSW) - collected by municipalities:
• MSW -from households institutions and small buisnesses
• 98% of MSW goes into landfills, while 2 percent is reused
• Developed countires are the cause for high msw
  Waste stream: the flow of solid waste that is recycled, incinerated, placed in a solid waste landfill, or disposed of in another way
• E waste goes stright to landfill because it's expensive to reuse
• toxic metals can end up in groundwater and surface water
• Total MSW increased since 1960 (population growth); per capita waste stabilized after 1990 (2 kg/person/day in US).
• Residences (60%) - Food scraps, paper, plastics.
• Businesses/institutions (40%) Packaging, electronics, construction debris
• E-waste (lead, mercury) small amounts of toxic waste.

Landfills

• Sanitary landfills are engineered to reduce environmental harm:
• Clay/plastic liners prevent groundwater.
• Leachate collection systems capture toxic liquids.
• Methane extraction (from anaerobic decomposition) reduces greenhouse gases.
• Capped with soil when full (can become parks, like Freshkills, NY).
  *Solutions; Leachate leaks, methane emissions, NIMBY opposition.

How Incineration Disposes of MSW

• Burns waste, reducing volume (~90%) and mass(~75%).
• Waste-to-Energy (WTE): Heat generates electricity.
• Air pollution (dioxins, heavy metals)
• Toxic ash (requiresspecial disposal).
• High costs(~$70/ton) and discourages recycling
• Why Some MSW Avoids Landfills/Incineration
  *Illegal dumping Tires, chemicals (to avoid tipping fees).
  *Ocean pollution Garbage patches(e.g., Great Pacific Garbage Patch).
  *Plastics harm marine life; medical waste risksfor humans.

Hazardous Waste Disposal

• Ignitability, corrosivity, reactivity, or toxicity.
• Batteries, pesticides, motor oil, e-waste.
• Secure landfills(more protective than MSW landfills).
• Chemical treatment (neutralization, stabilization).
• Recycling/reuse (e.g.,solvents, metals).
  *Key Laws: RCRA, CERCLA/Superfund, Brownfields Program

Three R's -Reduce, Reuse, Recycle

• Reduce (Most Sustainable)
• Minimize waste generation at the source.
• Double-sided printing (reduces paper use).
• Digital downloads (e.g., music instead of CDs).
• Saves energy, reduces pollution, and lowers costs.
  *Reuse Extending the life of a product before disposal.
  *Reusing glass milk bottles(sterilized and refilled).
  *Donating/selling used items(e.g., via eBay, thriftstores).
  Trade-offs: May require cleaning/repair (energy use).
  *Recycle (Least Efficient but Still Valuable)
  *Closed-loop:Recycled into the same product (e.g., aluminum cans).
  *Open-loop:Recycled into a different product (e.g., plastic bottles → fleece jackets).

Challenges

• Market volatility (e.g., China’s 2018 ban on imported recyclables).
• Contamination (non-recyclables mixed in).
• U.S. Recycling Rates(2018): ~34% of MSW recycled.
• Composting Organic Waste
• Aerobic decomposition of organic waste (food scraps, yard trimmings) into nutrient-rich humus.
• Reduceslandfill methane emissions (a potent GHG).
• Improve soil quality (water retention, nutrients).
• Requires aeration (turning piles) to avoid anaerobic decay.
• Carbon:Nitrogen Ratio (C:N) = 30:1

Life-Cycle Analysis & Integrated Waste Management

• Assess environmental impact of a product from raw material extraction to disposal.
• Limitations: Hard to compare impacts (e.g., incineration emissions vs. landfill methane).
• Economic comparisons (e.g., recycling revenue vs. landfill tipping fees).
• Energy audits(e.g., transport costsfor recyclables).
• Communities choose strategies based on local needs
• ). Cradle-to-Cradle Design (McDonough & Braungart) Products designed for easy disassembly/recycling Cradle-to-Cradle Design
• Upcycling: Waste → higher-value product
• Zero-Sort Recycling: Simplifies consumer participation

Module 52

*Biochemical Oxygen Demand (BOD): Measures oxygen used by microbes to decompose organic waste in water.
*High BOD = More polluted water (e.g., wastewater BOD = 200 mg/L vs. natural water BOD = 5–20 mg/L).
*Dead Zones:Low oxygen levels kill aquatic life (e.g., Gulf of Mexico near Mississippi River).
*Nutrient Release Global Dead Zones: 500+ identified (up from 4 in 1910).

Cultural Eutrophication

• Excess nitrogen/phosphorus from wastewater → algal blooms → oxygen depletion when algae decompose.
• Example: Chesapeake Bay (fertilizer runoff + sewage).

Septic Systems (Rural Areas)

• Components: (top), sludge (bottom), and septage (middle
  *Septic Tank: Separates waste into scum layer).
  *Leach Field: Soil filtersseptage, removing pathogens/nutrients.
  *Pros: No electricity needed.Cons: Requires periodic sludge removal (~every 5 years).

Sewage Treatment Plants (Urban Areas)

• Screensremove large debris; sludge settles out.
• Aerobic bacteria break down 85–90% of organic matter → CO_2 + inorganic nutrients (N, P).
• Removesremaining nutrients/metals via precipitation, UV/chlorine disinfection. doesn’t remove pharmaceuticals
• Heavy rain overwhelms plants → untreated sewage dumped into water bodies
  Impact: 23,000–75,000 overflows/year; illnesses cost million. Solutions: Infrastructure upgrades(e.g., Washington DC ’s $2.7 billion tunnel project).
  Rubber-lined ponds store waste from CAFOs
• CAFOs (Concentrated Animal Feeding Operations).
• Leaks(groundwater contamination), overflows (eutrophication), antibiotic/hormone pollution
  *Septic Systems(Rural), Sewage Treatment Plants(Urban),Combined Sewer Overflows(CSOs),Animal Waste *Treatment Hierarchy, Policy Challenges, Three Major Problemsfrom Wastewater
  *Oxygen Depletion - High BOD creates dead zones(e.g., Gulf of Mexico).
  *Nutrient Pollution leads to algal blooms. Pathogens cause diseases
  PRACTICE QUIZ FOR MODULES 50 + 52 Solutions provided in the original document. Not copying solutions as the goal is to provide notes. But practice quiz can be used to test understanding of the topics listed above.