Comprehensive Notes: Energy Conservation
If you were asked where your energy to work comes from, you would say food. Similarly, energy used for cooking comes from burning wood, coal, gas, or electricity. What would the world be like without light or heat from the sun, or electricity? Let us explore the sources of energy and why we desperately need to make wise use of them.
1 What is Energy & Its Sources?
Energy is defined simply as the capacity for doing work. The use of energy always brings about some change—a fan moves, a stove gives heat, a solar calculator works.
How does energy trace back to the sun? Fuels (wood, coal, oil, natural gas) get their energy because over millions of years, the sun's energy transformed dead plant material into fossil fuels beneath the earth's surface. Electricity is produced using moving water, steam, coal, or oil (all linked to the sun). Wind is caused by the sun changing air temperature. Geothermal energy is solar heat energy trapped by rocks deep within the earth.
2 Classification of Energy Sources
Renewable Sources
Sources with a nearly endless supply that can be replaced endlessly.
- Sunlight
- Wind
- Water
- Geothermal (unless extracted faster than it is trapped)
Non-Renewable Sources
Limited sources that will be exhausted after a certain number of years.
- Fossil Fuels (Coal, Oil, Natural Gas) - used faster than formed.
- Wood
- Nuclear fuels
- Electricity (since most rivers are already dammed to capacity and fossil fuels are used to generate it).
3 Why Do We Need to Conserve Energy?
Energy conservation involves using lesser energy for the same level of activity (e.g., using a pressure cooker to cook dal instead of an open pan). We must conserve for three vital reasons:
1. Demand Exceeds Supply
Increasing population, industrialization, traffic, and automation create an massive demand. Since we cannot endlessly increase supply, we must reduce demand through conservation.
2. Energy Saved is Energy Generated (S.O.S.)
Think of an energy bank. Energy saved locally (like avoiding decorative lights at a wedding) stays in the grid, preventing power cuts elsewhere. The motto is: Save on Something (S.O.S.).
3. Fuels are Limited
Fossil fuels are running out fast. Look at current projections:
| Fuel | Known Supplies | When likely to run out |
|---|---|---|
| Natural Gas | about 30 years | AD 2035 |
| Oil | about 50 years | AD 2055 |
| Coal | about 280 years | AD 2285 |
4 How to Conserve Energy (Actionable Steps)
At Home
- Use 40W tubelights instead of 100W bulbs (saves 60% power).
- Use electronic chokes and regulators.
- Clean lights/fixtures (dust reduces light by 30%).
- Use light-colored walls to reduce lighting needs by 40%.
- Only buy ISI marked appliances.
- Use pressure cookers with separators.
- Use Unnat Chullah (smokeless, 20-25% more heat efficient).
Farm & Workplace
- Maintain tractors. Poor maintenance loses 25% diesel.
- Drive tractors in correct gear (wrong gear increases fuel use by 30%).
- Dig lengthwise in fields to save diesel.
- Switch off computers/lights when leaving rooms.
- Encourage stairs instead of elevators.
On the Road
- Use a car pool instead of individual cars.
- Drive at slow, constant speeds.
- Maintain proper tyre pressure and keep engines tuned.
- Use light-sensitive switches/solar panels for street lights.
- Replace neon ad signs with solar-powered alternatives.
5 Energy Options for the Future
To stretch our non-renewable sources, we must supplement them with non-conventional (renewable) sources. They have a never-ending supply, are pollution-free, and can be produced locally.
1. Biogas
Product of fermentation of animal manure without air. Chiefly consists of methane gas. 2-3 animals provide enough for a family of 4.
Benefits: Excellent fertilizer (sludge), keeps environment clean, prevents eye/lung diseases from smoke.
2. Solar Energy
Solar Cooker: Black bottom box with glass top. Preserves ~2 kg wood/day. Solar Lighting: Solar cells convert daylight to electricity, stored in chemical batteries. Solar Heating: Used for bathing, drying crops, or small specialized refrigerators.
3. Hydel Energy (Micro-Hydel)
Large river sites are full. Small water drops from a great height yield massive power. Micro-hydel projects are cheap to install, supply remote areas, and ease national grid pressure.
4. Wind Energy
Propellers mounted on high towers. A 2-fold increase in wind speed yields an 8-fold increase in energy. Needs 20km/hr for economic electricity, 10km/hr for windpumps.
Process Flows & Diagrams
Classification of Energy Sources
(Unlimited)
(Limited)
Alternative Options for the Future
Sources
Golden Rules & Exam Tips
1 The Sun is the Ultimate Source
Almost all forms of energy on earth originate from the Sun. Fossil fuels are dead plants transformed by solar energy over millions of years. Moving water and wind are also driven by solar heat cycles.
2 Electricity is Non-Renewable
Even though water is renewable, electricity is classified as non-renewable. Why? Because major hydro-electric dams are already at max capacity, and the rest is generated by burning rapidly depleting fossil fuels.
3 The S.O.S Principle
Save on Something! Remember that "Energy saved is energy generated." By using an Unnat Chullah, a pressure cooker, or a 40W tubelight instead of a 100W bulb, you reduce the strain on the global energy grid.
4 Shift to Non-Conventional Energy
Because natural gas (AD 2035) and oil (AD 2055) will run out in our lifetimes, we must shift to non-conventional sources: Biogas (methane), Solar, Wind, and Micro-hydel, which are free and non-polluting.
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