Introduction to Sources of Energy
Energy is essential for all human activities and life processes.
Key points:
- Energy makes work possible
- Sources are classified as renewable & non-renewable
- Renewable = naturally replenished
- Non-renewable = finite & depleting
- Modern world moving toward clean energy
Types of Sources of Energy
Sources are grouped based on availability and replenishment.
Main categories:
- Renewable – naturally replenished
- Non-renewable – limited reserves
- Conventional – traditional (coal, oil…)
- Non-conventional – modern (solar, wind…)
Renewable Sources of Energy
Renewable sources are naturally replenished over short periods.
Advantages:
- Practically inexhaustible
- Very low or zero pollution
- Sustainable for future generations
- Reduces dependence on fossil fuels
Solar Energy
The Sun is the ultimate source of most energy on Earth.
Features:
- Captured using photovoltaic cells
- Completely clean & free
- Suitable for remote locations
- High initial cost but zero fuel cost
Wind Energy
Kinetic energy of wind is converted to electricity.
Key points:
- Clean and renewable
- Low operating cost after installation
- Best in windy coastal / highland areas
- Can affect birds & produce noise
Hydro Energy
Energy from moving or falling water.
Advantages:
- Very reliable & renewable
- Also used for irrigation & flood control
- Long life of plants
- Can disrupt river ecosystems
Biomass Energy
Energy from organic materials and waste.
Features:
- Renewable & reduces waste
- Biogas used for cooking & power
- Slurry works as good fertilizer
- Smoke pollution if burnt directly
Geothermal Energy
Heat energy from the Earth's interior.
Advantages:
- Available 24×7
- Very low emissions
- Low operational cost
- Limited to specific locations
Non-Renewable Sources of Energy
Finite resources formed over millions of years.
Characteristics:
- High energy density
- Easy to store & transport
- Major cause of air pollution & global warming
- Will deplete in future
Coal
Solid fossil fuel formed from ancient plant remains.
Uses & issues:
- Major source of electricity worldwide
- Used in steel & cement production
- High CO₂ and air pollutant emissions
- Mining causes land & health damage
Petroleum (Crude Oil)
Liquid fossil fuel formed from marine organisms.
Importance & concerns:
- Main fuel for transport
- Raw material for plastics & chemicals
- Oil spills harm marine life
- Burning causes global warming
Natural Gas
Cleanest burning fossil fuel (mainly methane).
Features:
- Used for cooking, heating & power
- Lower CO₂ than coal & oil
- Transported by pipelines or as LNG
- Methane leaks contribute to warming
Nuclear Energy
Energy from controlled nuclear fission.
Pros & cons:
- Very high energy from small fuel
- No CO₂ during electricity generation
- Radioactive waste needs safe storage
- Accident risk (Chernobyl, Fukushima)