Which of the following coasts is the largest tidal energy producing area in India ?

Question

UnlockIAS · Accepted Answer

Correct — D, Khambhat Coast. The Gulf of Khambhat, on the Gujarat coast, holds by far the largest tidal energy resource in India. The Ministry of New and Renewable Energy's assessment puts the country's tidal potential at roughly 8,000 MW, of which about 7,000 MW lies in the Gulf of Khambhat alone, about 1,200 MW in the Gulf of Kutch and under 100 MW in the Gangetic delta and the Sundarbans. The reason is geometry: Khambhat is a funnel-shaped gulf that narrows and shallows northward, so the incoming tide is squeezed and amplified, giving a tidal range of about 11 to 12 metres between high and low water — the largest anywhere on the Indian coast, against roughly 8 metres in the Gulf of Kutch and 6 to 7 metres in the Sundarbans. NOW THE HONEST PART, and a student should carry it away from this card: the stem says 'producing', and India produces no tidal power at all. There is not a single tidal power plant in operation anywhere in the country. Two were sanctioned and then dropped on cost — a 3.75 MW project at Durgaduani creek in the Sundarbans, taken up in 2007, and a 50 MW project in the Gulf of Kutch, taken up in 2011. The commission's key marks (d), and (d) is the right answer to the question the examiner meant to ask: which coast has the largest tidal energy POTENTIAL. Read as written, about production, the question has no correct answer, because the quantity produced everywhere in India is zero.

Why the other options are wrong — (a) The Gulf of Mannar, between the Tamil Nadu coast and Sri Lanka, is a shallow, broad, open embayment without the funnelling geometry that amplifies a tide, and its tidal range is small. What it is genuinely famous for is ecology, not energy: it is India's first Marine Biosphere Reserve, with coral reefs, seagrass beds, dugongs and the historic pearl banks. Candidates pick it because the name is familiar from the environment syllabus, not because of anything to do with tides.  (b) The Kerala coast is a smooth, largely straight shoreline on the Arabian Sea, fringed by lagoons and backwaters. It has no gulf or estuary that constricts the tide, and its tidal range is of the order of a metre — nowhere near the 11 to 12 metres of the Gulf of Khambhat. Kerala's renewable-energy interest lies elsewhere; tidal power is not a resource it possesses in any significant measure.  (c) The North Circars is the northern Andhra stretch of the east coast, a smooth deltaic shoreline built out by the Godavari and the Krishna. It is an emergent, gently shelving coast with a modest tidal range and, again, no funnel-shaped gulf. Its energy significance is entirely different — the Krishna–Godavari basin offshore is a hydrocarbon province, which is gas, not tides.

Concept: Tidal energy is extracted in two broad ways: by damming an estuary with a barrage so that water impounded at high tide is released through turbines at low tide, or by placing turbines directly in a fast tidal stream. Both depend on the same two variables — the tidal range and the speed of the tidal current — and both need a coastline shaped to amplify them. A funnel-shaped, progressively narrowing and shallowing gulf does exactly that, which is why the world's tidal power sites are gulfs and estuaries such as the Bay of Fundy, the Severn and La Rance rather than open coasts. In India that geometry occurs on the Gujarat coast, in the Gulfs of Khambhat and Kutch, and in a weaker form in the tidal creeks of the Sundarbans; the peninsular east and west coasts are comparatively straight and have small tidal ranges. Tidal energy is a non-conventional, renewable source, but unlike solar and wind it is also almost perfectly predictable, because tides are governed by astronomy rather than by weather.

State PCS 2022 Q58 — Geography PYQ with Answer

State PCS 2022 Q58 — Geography PYQ with Answer