Understanding Energy: Types, Units, and Sources

Posted on Dec 22, 2024 in Physics

Energy: Forms, Measurement, and Production

Types of Energy

  1. Electromagnetic Energy: Power manifested as radiation.
  2. Internal Energy: The sum of all energies less than that of the rest mass.
  3. Binding Energy or Chemical Energy: The energy that holds atoms and electricity together.
  4. Thermal Energy or Heat: Due to the motion of atoms and molecules, it is a form of kinetic energy.
  5. Nuclear Power: The energy contained in the nucleus of atoms; no more energy is rest mass.

Units of Energy Measurement

  1. Joule (J): The most important unit. It represents the work required to move a 100-gram mass one meter.
  2. Calorie or Kilocalorie (Cal): One Calorie (uppercase “C”) equals 1,000 calories (lowercase “c”) or 4,200 J. Calories are used in both diet and the refrigeration industry.
  3. Kilowatt-hour (kWh): Equals 3.6 million J. It is the unit used in electrical billing.
  4. Tonnes of Oil Equivalent (TOE): Almost 42,000 million joules. It is the most commonly used unit.
  5. Tonnes of Coal Equivalent (TCE): Almost 30,000 million joules. It is less commonly used.

Energy Types in Detail

  1. Kinetic Energy: The energy a body possesses due to its motion, proportional to its mass and the square of its speed.
  2. Potential Energy: The energy an elastic system, like a spring, possesses when its length changes, proportional to the square of the length change.
  3. Gravitational Potential Energy: The energy a body possesses due to its height, proportional to its mass and height.
  4. Electric Potential Energy: The energy a charge possesses in the presence of other charges, proportional to the charges. More charge means more electrical potential energy.
  5. Rest Energy: Relativistic energy, as described in Einstein’s theory of relativity, proportional to mass and the square of the speed of light. It represents a very large amount of energy.

Energy Conversion

Energy can be converted from one type to another without loss, as stated by the principle of conservation of energy: energy is neither lost nor destroyed, only transformed. A body gains energy when work is performed on it and loses energy when it performs work.

Energy Collection

  1. Primary Energy:
    • Non-renewable: Energy as it appears in nature before transformation, e.g., oil, coal, natural gas, uranium.
    • Renewable: Energy derived from the sun, wind, tides, heat waves, terrestrial heat, and biomass.
  2. Secondary Energy: Primary energies are converted into secondary energy for human use through physical, chemical, and biochemical mechanisms. The energy obtained is usually in the form of fuel (petrol, diesel) or electricity. Often, fuels are transformed into electricity.

Electricity Collection

There are four ways to generate electricity:

  1. Batteries: The first and oldest method.
  2. Solar Panels: Devices that convert sunlight into electricity.
  3. Piezoelectric Devices: Systems used in clocks, where pressing a crystal generates electricity (currently under research).
  4. Electric Generators: The most important and widely used method.

Wind Energy

Wind energy utilizes wind turbines, similar to electric generators, with a multiplier. The blades rotate slowly, while the generator spins rapidly. The generator converts the slow rotation of the blades into the fast rotation of the generator. Generators can be isolated and smaller, used to supply electricity to a specific location (e.g., a home). Depending on their size, they can be microgenerators or macrogenerators, often forming wind farms to supply electricity to the overall system.

Advantages of Wind Energy

  1. Clean energy, producing no smoke.
  2. Fast installation, typically within 1-2 months, or even days for micro/macro installations.
  3. Often located in areas lacking other uses.
  4. The land can still be used for other purposes.
  5. Scalable, allowing easy adjustment of production by enabling or disabling generators.

Disadvantages of Wind Energy

  1. Requires specific conditions: constant wind in intensity and orientation, without strong gusts.
  2. Instability: production depends on wind availability.
  3. Significant visual and landscape impact.
  4. Expensive distribution networks, as wind farms are usually far from consumption areas.
  5. The energy produced cannot be stored.
  6. Diffuse energy, requiring large wind farms.

Solar Power

Solar power comes from the sun. There are four ways to obtain energy from the sun:

  1. Photovoltaic: A panel that produces electricity when exposed to light.
  2. Thermosolar: Panels for hot water.
  3. Solar Towers: Electricity generation through convection.
  4. Thermoelectric: Mirrors oriented to a solar oven to heat oil and move a generator.

Advantages of Thermoelectric Solar Power

  1. Clean, producing no smoke.
  2. Lower environmental impact.
  3. High performance.
  4. Low maintenance costs.

Disadvantages of Thermoelectric Solar Power

  1. Limited locations, only where there is a lot of sun.
  2. Volatile: no sun, no energy.
  3. Expensive distribution networks.
  4. Electricity cannot be stored.
  5. Expensive installation.
  6. Expensive solar ovens.