Lecture 2 Nonrenewables

Nonrenewable Energy

  • Definition: Energy sources that exist in fixed amounts on Earth and cannot easily be replaced or regenerated.

Nonrenewable Energy Sources

  • Fossil Fuels: Formed from fossilized remains of ancient biomass over millions of years.

  • Nuclear Energy: Generated from uranium or other radioactive materials.

Fossil Fuels

  • Origin: Derived from decomposed organisms buried under sediments, leading to anaerobic decomposition.

  • Formation Conditions: High pressure and temperature lead to the concentration of hydrocarbons. Different depth and temperature conditions yield various types of fossil fuels.

Fossil Fuel Combustion

  • Process: Combustion involves a reaction between fossil fuels (hydrocarbons) and oxygen, releasing energy as heat.

  • Electricity Generation Steps:

    1. Heat water.

    2. Water turns into steam.

    3. Steam turns a turbine.

    4. Turbine powers a generator.

    5. Generator produces electricity.

Coal

  • Characteristics: Dirtier energy source, harmful to the environment, and considered unsustainable.

  • Types of Coal: Peat → Lignite → Bituminous → Anthracite (increasing quality).

Technology to Remove Pollutants from Coal

  • Baghouse Filters: Fabric filters that remove particulates.

  • Burning at Lower Temperatures: Reduces emissions.

  • Coal Gasification: Converts coal into syngas while filtering impurities.

  • Cyclone Separators: Use spinning and gravity to remove particulates.

  • Electrostatic Precipitators: Filter dust and smoke via electrostatic charge.

  • Fluidized-Bed Combustion: More air during burning reduces NOx, SOx, and particulates but may produce carcinogens.

  • Scrubbers and Sorbents: Remove acidic gases and convert pollutants into collectable compounds.

World Reserves - Coal

  • Global Use: Largest source for electricity production.

  • Reserves: US has the largest proven recoverable reserves, estimated to last about 300 years.

Major Pros and Cons of Coal

Pros

  • Abundant reserves (300 years at current consumption).

  • Stable and non-explosive.

  • By-products have potential usages.

Cons

  • Contributes to global warming through pollution.

  • High costs for control technologies.

  • Releases hazardous materials when burned.

Clean Coal

  • Definition: Technology aimed at reducing emissions from coal burning.

  • Methods: Includes underground CO2 storage, microbial fuel cells using biomass, and cleaner combustion processes.

Oil

  • Extraction: Trapped in sandstone, released by puncturing limestone.

  • Current Production: New wells exploit existing pressure; older wells need manual pumping.

World Reserves - Oil

  • Dominance: Middle East has the largest reserves.

  • Market Influences: Competition from China and India affects global oil prices.

Major Pros and Cons of Oil

Pros

  • Inexpensive with established transportation networks.

Cons

  • Environmental pollution and limited resources.

  • Liquid form facilitates transport but may leak.

Tar Sands

  • Composition: Mixture of clay, sand, water, bitumen requiring specialized refineries.

  • Extraction Methods: Strip-mining or in situ methods using steam.

Natural Gas (Methane)

  • Cleanest Fossil Fuel: Emits less pollution compared to others.

  • Production Shift: Significant growth in use for electricity generation in the US.

Methane Pros and Cons

Pros

  • Easily processed and transported when liquefied.

Cons

  • Leakage is a potent greenhouse gas.

Fracking

  • Technique: High-pressure injection of water, chemicals, and sand to extract oil and gas from rock.

  • Safety Risks: Potential groundwater contamination and environmental disruption.

Methane Hydrates

  • Source: Newly discovered methane located in ice at low temperatures and high pressure.

Oil Shale

  • Kerogen Content: Organic material converted to oil through heating.

  • Extraction Types: Surface mining and in situ heating methods.

Synfuels

  • Definitions: Fuels derived from coal, natural gas, or biomass through chemical processes.

Nuclear Energy

  • Nuclear Fission: Process where atom nuclei split, releasing energy; requires control for safe electricity production.

  • Energy Potential: Considerably higher than traditional fossil fuels.

Nuclear Fuel Types

  • U-235: Enriched and used for self-sustaining reactions, 3% in nuclear plants.

  • U-238: Most common uranium isotope, decaying to Pu-239.

Electricity Production from Nuclear Energy

  • Historical Context: Became a source in the 1960s, peaked then declined due to various factors.

Pros and Cons of Nuclear Power

Pros

  • Low emissions and reliable energy.

  • Long-lasting uranium sources.

Cons

  • Nuclear waste, mining impacts, and risks of accidents.

Nuclear Accidents

  • Major Events: Three Mile Island, Chernobyl, Fukushima.

Changes in Nuclear Power Usage

  • Decreased reliance owing to safety concerns, alternatives gaining ground.