Energy Unit Review Guide

Module 34: Fossil Fuels and Nonrenewable Energy Resources

  • Energy Units:

    • Joule (J): The SI unit of energy, defined as the amount of work done when a force of one newton moves an object one meter.

    • British Thermal Unit (Btu): The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

    • Calorie: The amount of heat required to raise the temperature of one gram of water by one degree Celsius.

    • Kilowatt Hour (kWh): A unit of energy equivalent to one kilowatt (1,000 watts) of power used for one hour.

  • Power Units:

    • Watt (W): The SI unit of power, defined as one joule per second.

    • Horsepower (hp): A unit of measurement for power, commonly used for engines and motors; one horsepower is equivalent to 746 watts.

  • Energy Sources:

    • Commercial Energy Sources: Energy sources that are sold in the marketplace (e.g., coal, oil, natural gas, nuclear).

    • Subsistence Energy Sources: Energy sources utilized for personal or household consumption, usually not traded in markets (e.g., firewood, animal waste).

  • Electricity Generation Plant: A facility for generating electricity, which can use various energy sources including fossil fuels, nuclear, and renewables.

Module 35: Energy Sources Overview

  • Coal: A fossil fuel derived from plant material that has undergone heat and pressure over millions of years.

  • Petroleum: Also known as crude oil; a liquid fossil fuel formed from the remains of ancient marine organisms.

  • Oil Sands: Mixtures of sand, clay, water, and bitumen, which can be mined to extract crude oil.

  • Liquid Coal: A form of energy derived from coal, generally referred to as a synthetic fuel made from coal through liquefaction.

  • Energy Intensity: A measure of the energy efficiency of an economy, typically defined as energy use per unit of GDP.

  • Hubbert Curve: A model that predicts the production rate of oil will rise until it reaches a peak (peak oil) and then decline.

  • Peak Oil: The point at which the extraction of oil reaches its maximum rate, after which production is expected to decline.

Module 36: Nuclear Energy

  • Fission: The process in which a large atomic nucleus splits into two or more smaller nuclei, releasing energy.

  • Fuel Rod: A cylindrical tube containing nuclear fuel used in reactors to initiate and maintain the nuclear fission reaction.

  • Control Rod: Made from materials that absorb neutrons; control rods are inserted into the reactor core to manage the rate of fission and to prevent overheating.

  • Three Mile Island Accident: A partial meltdown of a reactor at the Three Mile Island plant in Pennsylvania in 1979, which highlighted safety issues in nuclear reactors.

  • Chernobyl Accident: A catastrophic nuclear disaster that occurred in 1986 at the Chernobyl Nuclear Power Plant in the Soviet Union, leading to widespread radioactive contamination.

  • Fukushima Accident: A nuclear accident that occurred in 2011 in Japan, caused by a tsunami which disabled the power supply and cooling of three reactors.

  • Radioactive Waste: Waste that contains radioactive material, posing challenges for safe disposal and management.

  • Nuclear Fission vs. Fusion:

    • Fission: Splitting of atomic nuclei that releases energy.

    • Fusion: The process where two light atomic nuclei combine to form a heavier nucleus, releasing energy; this is the process that powers the sun.

  • Calculating Half-Lives: The time required for half of a radioactive substance to decay. The half-life can be calculated using the formula:
    N(t)=N0⋅(12)t/τN(t) = N_0 \cdot \left(\frac{1}{2}\right)^{t/\tau}
    where:

    • $N(t)$ is the remaining quantity of the substance,

    • $N_0$ is the initial quantity,

    • $t$ is the elapsed time, and

    • $\tau$ is the half-life.

  • How Does a Nuclear Reactor Work?:

    • A nuclear reactor generates heat through controlled nuclear fission.

    • This heat is used to produce steam that drives turbines to generate electricity.

Module 37: Energy Conservation

  • Passive Solar Design: Architectural design that maximizes solar gain in the winter and minimizes it in the summer for temperature control.

  • Energy Sources Classification:

    • Potentially Renewable: Resources that are renewable if managed sustainably (e.g., biomass).

    • Nondepletable: Resources that cannot be depleted (e.g., solar energy).

    • Renewable: Resources that can be replenished naturally (e.g., wind, solar, geothermal).

Module 38: Biofuels

  • Modern and Fossil Carbon:

    • Modern Carbon: Carbon derived from contemporary biological materials, considered carbon neutral.

    • Fossil Carbon: Carbon derived from fossil fuels, contributes to climate change.

  • Carbon Neutral: A state where the net carbon emissions are zero.

  • Ethanol: A biofuel produced through fermentation of sugars, commonly used in gasoline mixtures.

  • Biodiesel: A renewable fuel made from vegetable oils or animal fats typically used in diesel engines.

  • Hydroelectricity: Electricity generated by harnessing the energy of flowing water, with two main systems:

    • Run of the River System: A hydroelectric system that generates energy without a large reservoir, typically utilizing river flow.

    • Water Impoundment System: A system that stores water in a reservoir to control flow and generate electricity.

  • Tidal Energy: The energy generated from the rise and fall of tides, contributing to renewable energy sources.

Module 39: Active Renewable Energy Sources

  • Active Solar Energy: The use of technology to harness sunlight for energy, often through solar panels.

  • Photovoltaic Solar Cell: A device that converts sunlight directly into electricity using semiconductor materials.

  • Wind Energy: Energy harnessed from wind through the use of wind turbines.

    • Wind Turbine: A device that converts the kinetic energy of wind into mechanical power.

  • Geothermal Energy: Energy derived from the Earth's internal heat, often used for heating and electricity generation.

  • Hydrogen Fuel Cell: A device that converts the chemical energy from hydrogen into electricity through a chemical reaction with oxygen, often using electrolysis to produce hydrogen.

Module 40: Pros and Cons of Renewable Energy Sources

  • Pros:

    • Sustainable and environmentally friendly.

    • Reduces dependence on fossil fuels.

    • Can create jobs in installation and maintenance.

  • Cons:

    • Initial costs for infrastructure can be high.

    • Some renewable sources can be intermittent (e.g., solar and wind).

  • “Smart Grid” Technology: An advanced electrical grid that uses digital technology to monitor and manage the transport of electricity from all generation sources, enabling more efficiency and integration of renewable sources.