Energy resources

Energy is obtained from various natural sources and converted into useful forms such as electricity. Different energy sources have advantages and disadvantages based on renewability, availability, reliability, scale, and environmental impact.

Energy resources

Fossil Fuels (Coal, Oil, Natural Gas)

• Energy Source: Chemical energy stored in coal, oil, and natural gas.

• Process:

  • Fossil fuels are burned in a boiler, heating water.

  • Steam turns a turbine.

  • The turbine drives a generator, producing electricity.

• Advantages:

  • Reliable energy supply.

  • Large-scale electricity generation.

• Disadvantages:

  • Non-renewable (finite supply).

  • Produces carbon dioxide (CO₂), contributing to climate change.

  • Causes air pollution (sulfur dioxide leads to acid rain).

Biofuels (Plant and Animal-Based Fuels)

• Energy Source: Chemical energy in organic materials like wood, crops, and animal waste.

• Process: Similar to fossil fuels—biofuels are burned to heat water and produce steam, which drives a turbine and generator.

• Advantages:

  • Renewable (can be replenished).

  • Carbon neutral (absorbs CO₂ while growing, releases it when burned).

• Disadvantages:

  • Large land use (competes with food production).

  • Deforestation can occur to make space to grow the crops.

Hydroelectric Power (Dams)

• Energy Source: Gravitational potential energy of water stored behind a dam.

• Process:

  • Water is released from the dam, spinning a turbine.

  • The turbine drives a generator, producing electricity.

• Advantages:

  • Renewable and does not produce CO₂.

  • Reliable (constant energy supply).

• Disadvantages:

  • Destroys ecosystems (flooding land).

  • High construction costs.

Tidal Power

• Energy Source: Energy from rising and falling tides.

• Process: Tidal movement spins turbines, generating electricity.

• Advantages: 

  • Renewable 

  • Does not produce CO₂.

  • Reliable (tides are predictable).

• Disadvantages: 

  • Expensive

  • Limited locations.

Wave Power

• Energy Source: Kinetic energy from ocean waves.

• Process: Waves move floating generators, converting motion into electricity.

• Advantages: 

  • Renewable.

• Disadvantages: 

  • Unreliable (depends on weather).

  • Can harm marine life

Geothermal Energy

• Energy Source: Thermal energy from Earth's hot rocks and magma.

• Process:

  • Hot underground water produces steam.

  • Steam turns a turbine and generator.

• Advantages:

  • Renewable.

  • Minimal CO₂ emissions.

• Disadvantages:

  • Only available in volcanic areas.

  • High drilling costs.

Nuclear Power (Uranium and Plutonium)

• Energy Source: Nuclear energy from splitting uranium/plutonium atoms (fission).

• Process:

  • Nuclear fission releases heat, heating water.

  • Steam drives a turbine and generator.

• Advantages:

  • No CO₂ emissions.

  • Produces large amounts of energy.

  • Reliable

• Disadvantages:

  • Produces radioactive waste.

  • High accident risks (e.g., Chernobyl, Fukushima).

  • Non-renewable

Solar Cells (Photovoltaic Panels)

• Energy Source: Light energy from the Sun.

• Process: Solar panels convert light into electricity (photoelectric effect).

• Advantages:

  • Renewable and no emissions.

  • Low operating costs.

• Disadvantages:

  • Unreliable (only works in sunlight).

  • High installation cost.

Solar Panels for Heating & Wind Energy

Solar Heating Panels

• Energy Source: Infrared radiation from the Sun.

• Process:

  • Solar panels heat water directly for homes.

• Advantages: 

  • Renewable.

  • No emissions.

• Disadvantages: 

  • Only works in daylight.

Wind Power

• Energy Source: Kinetic energy from wind.

• Process:

  • Wind spins turbine blades.

  • The turbine drives a generator to produce electricity.

• Advantages:

  • Renewable.

  • No pollution.

  • Low operating costs.

• Disadvantages:

  • Unreliable (depends on wind speed).

  • Noisy and visually intrusive.

Efficiency of energy transfer

Not all input energy is converted into useful energy. Some energy is wasted as heat, sound, or other forms.

Efficiency of energy transfer equations

Efficiency Equations:

or

Example Calculation:

• A machine inputs 500 J of energy and produces 200 J of useful energy.

• Efficiency:

200/500 × 100 = 40%

Key Idea: The higher the efficiency, the less energy is wasted.

The sun as an energy source