2 real PYQs·1 concept ↓·2 concept drills·Asked 2016 · 2022
📝 Drill the PYQs
Renewable Energy
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📚 The concepts · 1
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Renewable Energy Sources — Solar, Wind, Biomass, Geothermal, Ocean
›*India's renewable energy targets:**
›Government target: 175 GW by 2022 — breakdown: 100 GW solar + 60 GW wind + 10 GW bio-power + 5 GW small hydro
›Total installed capacity from renewable energy (April 2016): 42,800 MW
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Renewable energy is generated from natural resources continuously replenished — sunlight, geothermal heat, wind, tides, water, and biomass. Unlike non-renewable fuels, renewable energy cannot be exhausted. Most sources are fairly non-polluting (clean energy), BUT biomass is a major contributor to indoor pollution despite being renewable.
**Types of renewable energy:**
- Solar energy (sunlight)
- Hydel energy (water)
- Biomass (firewood, animal dung, biodegradable waste, crop residues when burnt)
- Geothermal (hot dry rocks, magma, hot water springs, geysers)
- Ocean thermal (waves and tidal energy)
- Co-generation (two forms of energy from one fuel)
- Fuel cells
All key facts
›*India's renewable energy targets:**
›Government target: 175 GW by 2022 — breakdown: 100 GW solar + 60 GW wind + 10 GW bio-power + 5 GW small hydro
›Total installed capacity from renewable energy (April 2016): 42,800 MW
›Distribution by sector: State sector ~39%, Private sector ~31%, Centre ~29%
›*Solar energy:**
›India potential: 35 MW/km² using solar PV and solar thermal
›Solar energy incident on India's land area: ~5,000 trillion kWh/year; most parts receive 4–7 kWh/sq.m/day
›States with highest solar radiation: Rajasthan, northern Gujarat, parts of Ladakh, Andhra Pradesh, Maharashtra, Madhya Pradesh
›Two technology routes:
›1. Photovoltaic (PV) Electricity: PV cells with positive and negative semiconductor layers; photons absorbed → electrons freed → voltage differential → current (DC converted to AC via inverters)
›2. Solar-Thermal (CSP — Concentrated Solar Power): uses mirrors/parabolic troughs to focus sunlight → heat fluid → generate steam → turbine; commonly used fluids: synthetic oil, molten salt, pressurised steam
›*National Solar Mission:**
›Formulated by Government of India and state governments
›Aim: make India global leader in solar energy
›Revised target: 100 GW installed solar capacity by 2022
›*International Solar Alliance (ISA):**
›Launched at COP21 Paris (30th November 2015)
›Platform for cooperation among 121 solar resource-rich countries lying fully/partially between Tropic of Cancer and Tropic of Capricorn
›Formal name: International Agency for Solar Policy and Application (IASPA)
›Secretariat: National Institute of Solar Energy, Gurgaon
›Objectives: force down prices by driving demand, standardise solar technologies, foster R&D
›PM coined term "Surya Putra" for nations between Tropics of Cancer and Capricorn ("Sunshine Countries")
›IESS 2047: India Energy Security Scenarios 2047 calculator — explores potential of future energy scenarios
›*Luminescent Solar Concentrators (LSC):**
›Thin sheet of polymer (PMMA) doped with luminescent species (organic dyes, quantum dots, rare earth complexes)
›Traps solar radiation over large area, directs energy to PV cells at edges
›Key advantage: collects BOTH direct and diffuse solar radiation (no sun tracking required)
›Unlike typical concentrating systems — can work in cloudier northern climates
›Excellent for building-integrated photovoltaics (BIPV)