Ch 14 explores various sources of energy — conventional (fossil fuels, hydro, biomass) and non-conventional (solar, wind, tidal, nuclear) — comparing their advantages, limitations, and environmental impact.
Fossil fuels (coal, petroleum, natural gas): formed over millions of years, non-renewable, cause pollution and global warming. Thermal power plant: burns coal → steam → turbine → electricity. Hydro power: flowing/falling water → turbine → electricity (renewable, but needs dams, displaces people). Biomass: wood, cow dung; biogas (gobar gas): methane-rich, clean fuel from anaerobic decomposition.
Solar energy: solar cells (photovoltaic, Si-based), solar cookers, solar water heaters. Wind energy: kinetic energy of wind turns turbines (needs wind speed > 15 km/h). Ocean energy: tidal (due to moon's gravity), wave energy, ocean thermal energy (temperature difference). Geothermal: heat from Earth's interior → steam → electricity. Nuclear fission: U-235 splits → huge energy; fusion: H atoms combine → even more energy (Sun's energy source).
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Fossil fuels are non-renewable — they took millions of years to form and are being consumed much faster than they form. Burning them releases CO₂ (global warming), SO₂ (acid rain), and particulates (pollution). They are finite — oil reserves may last only 40-50 years at current rates. We need sustainable alternatives.
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