♻️AP Environmental Science Unit 6 – Energy Resources & Consumption

Energy Basics

• Energy the capacity to do work or cause change
• Kinetic energy energy of motion (wind, flowing water)
• Potential energy stored energy due to position or configuration (chemical bonds, gravitational pull)
• Law of Conservation of Energy states that energy cannot be created or destroyed, only converted from one form to another
  • Energy transformations occur when energy changes from one form to another (chemical energy in gasoline converted to kinetic energy in a car's motion)
• Power the rate at which energy is transferred or converted, measured in watts (W) or joules per second (J/s)
• Efficiency the ratio of useful energy output to total energy input, expressed as a percentage
  • High efficiency minimizes energy waste and maximizes useful work (LED light bulbs)

Types of Energy Resources

• Renewable energy resources naturally replenished on a human timescale (solar, wind, hydropower)
  • Sustainable and have lower environmental impact compared to non-renewable sources
• Non-renewable energy resources finite and depleted faster than they can be replenished (fossil fuels, nuclear)
  • Formed over millions of years and once consumed, cannot be replaced within human lifetimes
• Fossil fuels organic matter converted into coal, oil, or natural gas over geologic time
• Nuclear energy released through nuclear fission or fusion reactions
• Alternative energy sources include geothermal, tidal, and biomass
  • Offer potential for cleaner energy production but may have limitations or drawbacks (intermittency, high costs)

Fossil Fuels

• Coal formed from the remains of ancient plants subjected to heat and pressure over millions of years
  • Burned in power plants to generate electricity but releases pollutants (particulate matter, sulfur dioxide, mercury)
• Oil (petroleum) liquid fossil fuel formed from the remains of marine organisms
  • Refined into gasoline, diesel, and other products used for transportation and industrial processes
• Natural gas primarily composed of methane, formed alongside oil deposits
  • Cleaner burning than coal or oil but still emits greenhouse gases when combusted
• Hydraulic fracturing (fracking) involves injecting high-pressure water, sand, and chemicals into shale rock to release trapped oil and gas
  • Controversial due to potential groundwater contamination and induced seismicity
• Fossil fuel combustion releases carbon dioxide (CO2), a greenhouse gas that contributes to climate change
• Peak oil the point at which global oil production reaches its maximum rate, followed by a decline in production
  • Raises concerns about energy security and the need for alternative energy sources

Renewable Energy Sources

• Solar energy harnessed from the sun's radiation using photovoltaic (PV) cells or solar thermal collectors
  • PV cells convert sunlight directly into electricity, while solar thermal systems use mirrors to concentrate heat for power generation
• Wind energy captured by wind turbines that convert kinetic energy into electricity
  • Offshore wind farms have higher and more consistent wind speeds compared to onshore installations
• Hydropower generated by the flow of water through turbines in dams or run-of-river systems
  • Provides reliable baseload power but can disrupt aquatic ecosystems and displace communities
• Geothermal energy derived from heat within the Earth's crust, accessed through wells or geothermal heat pumps
  • Suitable for heating, cooling, and electricity generation in geologically active regions (Iceland, New Zealand)
• Biomass organic matter used as fuel, including wood, crops, and waste products
  • Carbon-neutral if regrowth absorbs CO2 released during combustion, but may compete with food production or natural habitats
• Tidal energy harnessed from the rise and fall of ocean tides using turbines or barrages
  • Predictable but limited to coastal areas with high tidal ranges (Bay of Fundy, Canada)

Nuclear Energy

• Nuclear fission splitting of heavy atomic nuclei (uranium-235) releases large amounts of energy
  • Controlled fission reactions in nuclear power plants generate heat to produce steam and drive turbines
• Nuclear fusion combining light atomic nuclei (hydrogen) to form heavier elements, releasing energy
  • Occurs naturally in the sun and stars but challenging to replicate in a controlled manner on Earth
• Advantages of nuclear power include high energy density, low greenhouse gas emissions, and reliable baseload generation
• Disadvantages include high construction costs, risk of accidents (Chernobyl, Fukushima), and long-term radioactive waste storage
  • Nuclear waste remains hazardous for thousands of years and requires secure disposal in deep geological repositories
• Uranium enrichment process of increasing the concentration of fissile uranium-235 isotope for use in nuclear fuel
  • Raises proliferation concerns if enriched to weapons-grade levels (>90% U-235)
• Nuclear fusion research aims to develop a clean and virtually limitless energy source
  • Challenges include maintaining stable plasma confinement and achieving net energy gain (ITER project)

Energy Consumption Patterns

• Global energy consumption has increased dramatically since the Industrial Revolution, driven by population growth and economic development
  • Fossil fuels (coal, oil, natural gas) currently dominate the global energy mix
• Developed countries have higher per capita energy consumption compared to developing nations
  • United States and Canada among the highest per capita consumers due to energy-intensive lifestyles and industries
• Energy poverty lack of access to modern energy services, affecting over 1 billion people worldwide
  • Limits economic opportunities, education, and health outcomes in developing regions (sub-Saharan Africa, South Asia)
• Energy efficiency improvements help reduce energy demand without compromising quality of life
  • Includes high-efficiency appliances, building insulation, and fuel-efficient vehicles (hybrid and electric cars)
• Energy conservation involves changing behaviors to reduce energy consumption
  • Examples include turning off lights, adjusting thermostat settings, and using public transportation
• Rebound effect occurs when efficiency improvements lead to increased energy use due to lower costs or improved performance
  • Mitigating the rebound effect requires policies that incentivize conservation and discourage wasteful consumption

Environmental Impacts

• Fossil fuel combustion releases greenhouse gases (CO2, methane) that contribute to global climate change
  • Impacts include rising sea levels, more frequent and intense extreme weather events, and shifts in ecosystems and agriculture
• Air pollution from burning fossil fuels causes respiratory illnesses, acid rain, and reduced visibility
  • Particulate matter (PM2.5) and ground-level ozone are particularly harmful to human health
• Oil spills devastate marine ecosystems and coastal communities
  • Exxon Valdez (1989) and Deepwater Horizon (2010) spills had long-lasting environmental and economic impacts
• Mining and drilling operations can degrade land, disrupt wildlife habitats, and contaminate water resources
  • Mountaintop removal coal mining in Appalachia has buried streams and valleys, displacing communities
• Nuclear accidents release radioactive material into the environment, with long-term health and ecological consequences
  • Chernobyl (1986) and Fukushima (2011) disasters led to exclusion zones and ongoing remediation efforts
• Renewable energy sources have lower environmental impacts but still require land, materials, and infrastructure
  • Wind turbines can cause bird and bat fatalities, while solar panels require rare earth elements in their production

Future of Energy

• Transition to a low-carbon energy system is crucial for mitigating climate change and ensuring long-term sustainability
  • Requires rapid deployment of renewable energy, energy efficiency, and electrification of transportation and heating
• Energy storage technologies (batteries, pumped hydro, hydrogen) are essential for integrating variable renewable sources into the grid
  • Lithium-ion batteries have seen significant cost reductions and performance improvements in recent years
• Smart grids use advanced sensors, communication, and control technologies to optimize energy distribution and consumption
  • Enable demand response programs, distributed generation, and integration of electric vehicles
• Carbon pricing mechanisms (carbon taxes, cap-and-trade) aim to internalize the environmental costs of fossil fuels and incentivize clean energy adoption
  • Successful examples include British Columbia's carbon tax and the European Union's Emissions Trading System
• International cooperation and policies are needed to address the global nature of energy and climate challenges
  • Paris Agreement (2015) aims to limit global temperature rise to well below 2°C above pre-industrial levels
• Energy equity ensuring access to affordable, reliable, and clean energy for all is crucial for sustainable development
  • Initiatives like the UN's Sustainable Energy for All (SEforALL) work to close the energy access gap in developing countries