Energy Conservation and Crisis

  • Energy is conserved in physical or chemical processes, meaning it can’t be created or destroyed.
  • But, we still face an energy crisis. This is because energy comes in different forms, and when one form is converted into another (like potential energy turning into sound or light), not all energy remains usable.
  • In real-life processes, energy tends to dissipate into less usable forms (e.g., heat, sound) which can’t be reused for work.

What Makes a Good Source of Energy?

  • A good energy source should:
    1. Provide a lot of work per unit of mass/volume.
    2. Be easily available and accessible.
    3. Be easy to store and transport.
    4. Be economical.
  • Questions to consider when choosing a fuel:
    1. How much heat does it release when burned?
    2. Does it produce a lot of smoke?
    3. Is it easily available?
    • You should also think about other factors like safety, environmental impact, and efficiency.

Conventional Sources of Energy

  • Fossil Fuels:
    • Fossil fuels like coal and petroleum have been major energy sources for many years. These fuels are non-renewable (limited supply) and are formed over millions of years.
    • Disadvantages: They contribute to air pollution (acid rain, greenhouse gases like CO₂), and are not sustainable.
    • Fossil fuels are used in power plants to generate electricity, but their excessive use is unsustainable.
  • Thermal Power Plants:
    • In thermal power plants, fossil fuels are burned to heat water, creating steam to turn turbines and generate electricity.
    • The plants are often built near coal/oil fields to reduce transportation costs.
    • This process is efficient for electricity transmission.
  • Hydro Power Plants:
    • Hydro power plants use the potential energy of water stored in dams to generate electricity.
    • Water falls from a height, turning turbines to generate power.
    • Hydro power is renewable, as water is replenished naturally.
    • Problems: Dams can cause displacement of people, submerge agricultural land, and damage ecosystems. Methane is released when submerged vegetation rots.
  • Wind Energy:
    • Wind energy is harnessed using windmills that convert the kinetic energy of the wind into mechanical energy, which is then used to generate electricity.
    • A single windmill provides small amounts of energy, but large wind farms can generate significant power.
    • Advantages: It’s renewable, eco-friendly, and has no recurring costs.
    • Limitations: Wind speed must be high enough (greater than 15 km/h), and the wind must blow consistently. The setup costs are high, and maintenance can be expensive.

Bio-Mass Energy:

  • Bio-mass includes plant and animal products, such as wood, cow-dung, crop residues, and sewage, which can be used as fuel.
  • Bio-gas: Bio-gas is produced from the decomposition of organic waste in the absence of oxygen, producing methane and other gases.
    • Advantages: It burns cleanly, has high heating capacity, and produces no ash.
    • Uses: It can be used for lighting, cooking, and as a manure source for agriculture.

Energy Selection for Specific Purposes:

  • When choosing energy sources or fuels, consider factors like the energy needs for a specific task (e.g., cooking vs. heating), availability, environmental impact, and efficiency. For example:
    • A fuel used for cooking may not be suitable for heating a room in winter.
    • The choice of fuel may differ depending on where you live (e.g., urban vs. rural areas).

Alternative or Non-Conventional Sources of Energy

With technological advances, the demand for energy is increasing. Our lifestyles are changing, and machines help us do more tasks. Industrialization is also raising our basic needs and standards of living. To meet this growing demand, we need to develop more energy sources, use known sources more efficiently, and explore new ones. New sources require specific technologies for capturing and storing energy. While some suggest returning to ancient practices to conserve energy, the feasibility of this idea is worth considering.

1. Solar Energy

The Sun has been emitting energy for billions of years, and will continue for many more. A small amount of this energy reaches Earth’s surface after being absorbed by the atmosphere. India receives large amounts of solar energy throughout the year, estimated at over 5,000 trillion kWh annually. The “solar constant” is the energy received per unit area exposed to the Sun.

A black surface absorbs more heat than a white one, and solar devices like cookers and water heaters use this principle. Solar cells convert sunlight into electricity, but they are costly and inefficient. Despite this, they are used in scientific applications like satellites and remote areas where electricity transmission is impractical. The cost of solar cells remains a limitation for domestic use.

2. Energy from the Sea

  • Tidal Energy: The rise and fall of sea levels, caused by the moon’s gravitational pull, generate tidal energy. Dams are built in narrow sea openings, and turbines convert this energy into electricity.
  • Wave Energy: Huge waves near the shore, created by strong winds, contain kinetic energy. Devices capture this energy to generate electricity.
  • Ocean Thermal Energy: The temperature difference between warm surface water and cooler deep water in oceans can be used to generate energy by heating a volatile liquid like ammonia. This process requires a temperature difference of at least 20°C.

3. Geothermal Energy

Molten rocks in Earth’s crust form “hot spots,” where underground water turns into steam. This steam is used to generate electricity. Geothermal energy is inexpensive but limited to certain regions with hot spots, such as New Zealand and the USA.

4. Nuclear Energy

Nuclear energy is produced by splitting heavy atoms like uranium through a process called nuclear fission. This releases vast amounts of energy. Nuclear reactors use this energy to produce electricity, but there are risks, including radioactive waste and potential environmental contamination. While nuclear power is expensive and dangerous, some countries rely heavily on it.

  • Nuclear Fusion: A safer process of nuclear energy generation, where light nuclei like hydrogen fuse to create heavier nuclei. Fusion occurs in stars like the Sun, and although it releases immense energy, it requires extreme conditions, making it difficult to achieve on Earth.

5. Environmental Consequences of Energy Sources

All energy sources have some environmental impact. For example, fossil fuels cause air pollution, while solar cells, despite being cleaner, can cause environmental damage during production. Researchers are working to create more durable devices that cause less harm over time. The choice of an energy source depends on its efficiency, cost, ease of use, and environmental impact.

6. Exhaustible vs. Renewable Energy

Fossil fuels are exhaustible (non-renewable) sources, meaning they will eventually run out. Renewable energy sources, like biomass, wind, and solar, can be replenished naturally. We need to consider both the sustainability and environmental impact of energy sources.

Summary

  • Energy demand is increasing with our lifestyle changes.
  • We need to develop both new sources and improve existing technologies to meet this demand.
  • Solar, tidal, wave, geothermal, and nuclear energy are alternative sources, each with its pros and cons.
  • Environmental factors, including cost, efficiency, and sustainability, influence the choice of energy sources.

THESE ALL ARE THE NOTES OF CHAPETR 14. AND AFTER SOME TIME YOU GET IMPORTANT QUESTIONS HERE. *#THANKS FOR VISITING, VISIT AGAIN#* 😊